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Cannabis use disorder and the lungs
Abstract
Cannabis is one of the world's most widely used recreational drugs and the second most commonly smoked substance. Research on cannabis and the lungs has been limited by its illegal status, the variability in strength and size of cannabis cigarettes (joints), and the fact that most cannabis users also smoke tobacco making the effects hard to separate. Despite these difficulties, the available evidence indicates that smoking cannabis causes bronchitis and is associated with changes in lung function. The pattern of effects is surprisingly different from that of tobacco. Whereas smoking cannabis appears to increase the risk of severe bronchitis at quite low exposure, there is no convincing evidence that this leads to chronic obstructive pulmonary disease. Instead cannabis use is associated with increased central airway resistance, lung hyperinflation, and higher vital capacity with little evidence of airflow obstruction or impairment of gas transfer. There are numerous reports of severe bullous lung disease and pneumothorax among heavy cannabis users, but convincing epidemiological data of an increased risk of emphysema or alveolar destruction are lacking. An association between cannabis and lung cancer remains unproven with studies providing conflicting findings.
... Furthermore, it has been suggested that drug use may impair the ability of the immune system to clear lung infections, making people more susceptible to respiratory diseases such as tuberculosis and pneumonia (Murtha et al., 2023). Furthermore, research has shown that drug usage can raise the prevalence of respiratory symptoms, including persistent coughing, sputum production, dyspnea, hoarseness, and tightness in the chest (Gracie & Hancox, 2021;Xie & Li, 2020) Sleep is important for rest and recovery for living beings, including humans. Sleep disturbance contributes to the beginning as well as to continuing substance use. ...
... Smoking cigarette and using substances such as cannabis are associated with coughing, wheezing, sputum production and dyspnea (Gracie & Hancox, 2021). The study found that cannabis smokers reported coughing nearly twice as often and sputum four times as often, and that cannabis use was associated with cough, sputum production, wheezing, shortness of breath, and chronic bronchitis. ...
... The study found that cannabis smokers reported coughing nearly twice as often and sputum four times as often, and that cannabis use was associated with cough, sputum production, wheezing, shortness of breath, and chronic bronchitis. However, most cannabis users also smoke cigarette, and the study was unable to distinguish between those who used only cannabis and those who used cigarette (Gracie & Hancox, 2021). Many studies in the literature have reported increased respiratory symptoms in patients with SUD, similar to our findings (Aldington et al., 2007;Buster et al., 2002;Macleod et al., 2015). ...
There is evidence that substance use and smoking cause someadverse effects on the respiratory system. The aim of this studywas to assess dyspnea severity, respiratory muscle strength,cough capacity, and sleep quality in people with substance usedisorder (SUD). Forty eight individuals with SUD and 28 activecigarette smokers participated in the study. Participants’ dys-pnea severity was assessed using the Modified MedicalResearch Council Scale, respiratory muscle strength was mea-sured with a portable electronic mouth pressure device, peakcough flow was assessed with a Peak Flow Meter, and sleepquality was determined using the Pittsburgh Sleep QualityIndex (PSQI). The amount of daily cigarette smoking and dys-pnea severity were significantly higher in individuals with SUD(p < .001). Peak cough flow values, maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), MIP (%predicted), and MEP (%predicted) were not significantly differentbetween the SUD patients and the active cigarette smokers(p > .05). However, PSQI sub-parameters such as subjective sleepquality, sleep latency, habitual sleep efficiency, use of sleepingmedication, and total scores showed significant differencesbetween the SUD patients and the active cigarette smokers(p < .05, p < .001, p = .03, p < .001, p < .001, respectively).Individuals with SUD were found to have higher dyspnea andpoorer sleep quality than active smokers. However, respiratorymuscle strength and cough capacities were similar.
... Cannabis users attend the emergency department more frequently due to respiratory symptoms, particularly with exacerbations of bronchial asthma, further discussed below [41,42]. Symptoms of bronchitis improved in patients who quit frequent cannabis smoking [43]. ...
... Inhaling cannabis, much like tobacco, has been linked to the onset of chronic bronchitis symptoms such as cough, dyspnea, wheezing, and increased sputum production. It is important to note that a significant portion of individuals experiencing these symptoms were also tobacco smokers [43]. Similarly, Gates et al. found that chronic cannabis use (after adjustment for tobacco use) is uniformly associated with a higher prevalence of chronic bronchitis symptoms [47]. ...
... Whereas smoking cannabis appears to increase the risk of severe bronchitis [47], even at low exposure, there is no convincing evidence that this leads to COPD. High-burden cannabis exposure was associated with increased central airway resistance, reflected by a decrease in specific airway conductance and an increase in airway resistance [59] and lung hyperinflation [60], but with little evidence of actual airflow obstruction or impairment of gas transfer [43,46]. A recent systematic meta-analysis and review by Ghasemiesfe et al. concluded that there is currently insufficient evidence supporting an association between cannabis-only use and bronchial obstruction [61]. ...
Abstract
The diminished perception of the health risks associated with the consumption of cannabis (marijuana) lead to a progressive increase in its inhalational use in many countries. Cannabis can be smoked through the use of joints, spliffs and blunts, and it can be vaporised with the use of hookah or e-cigarettes. Delta-9 tetrahydrocannabinol (THC) is the main psychoactive component of cannabis smoke but contains numerous other substances. While the recreational use of cannabis smoking has been legalised in several countries, its health consequences have been underestimated and undervalued. The purpose of this review is to critically review the impact of cannabis smoke on the respiratory system.
Cannabis smoke irritates the bronchial tree and is strongly associated with symptoms of chronic bronchitis, with histological signs of airway inflammation and remodelling. Altered fungicidal and antibacterial activity of alveolar macrophages, with greater susceptibility to respiratory infections, is also reported. The association with invasive pulmonary aspergillosis in immunocompromised subjects is particularly concerning. Although cannabis has been shown to produce a rapid bronchodilator effect, its chronic use is associated with poor control of asthma by numerous studies. Cannabis smoking also represents a risk factor for the development of bullous lung disease, spontaneous pneumothorax and hypersensitivity pneumonitis. On the other hand, no association with the development of chronic obstructive pulmonary disease was found. Finally, a growing number of studies report an independent association of cannabis smoking with the development of lung cancer.
In conclusion, unequivocal evidence established that cannabis smoking is harmful to the respiratory system. Cannabis smoking has a wide range of negative effects on respiratory symptoms in both healthy subjects and patients with chronic lung disease. Given that the most common and cheapest way of assumption of cannabis is by smoking, healthcare providers should be prepared to provide counselling on cannabis smoking cessation and inform the public and decision-makers.
... Acute cannabis smoking can cause coughing and throat irritation (Hall, 2015). Chronic cannabis smoking is linked to chronic bronchitis and there is growing evidence for cannabis-related impairment of respiratory function including wheezing, exercise-related shortness of breath, nocturnal wakening with chest tightness, morning sputum, coughing, chest sounds and phlegm production (Agrawal et al., 2012;Campeny et al., 2020;Gracie & Hancox, 2021). Of note, the effects on the respiratory system occur independently of tobacco use but tobacco and cannabis use can have an additive effect , including central airway resistance, lung hyperinflation and higher vital capacity (Gracie & Hancox, 2021). ...
... Chronic cannabis smoking is linked to chronic bronchitis and there is growing evidence for cannabis-related impairment of respiratory function including wheezing, exercise-related shortness of breath, nocturnal wakening with chest tightness, morning sputum, coughing, chest sounds and phlegm production (Agrawal et al., 2012;Campeny et al., 2020;Gracie & Hancox, 2021). Of note, the effects on the respiratory system occur independently of tobacco use but tobacco and cannabis use can have an additive effect , including central airway resistance, lung hyperinflation and higher vital capacity (Gracie & Hancox, 2021). There is no convincing evidence that cannabis smoking leads to chronic obstructive pulmonary disorder (COPD) independently of tobacco use (Gracie & Hancox, 2021). ...
... Of note, the effects on the respiratory system occur independently of tobacco use but tobacco and cannabis use can have an additive effect , including central airway resistance, lung hyperinflation and higher vital capacity (Gracie & Hancox, 2021). There is no convincing evidence that cannabis smoking leads to chronic obstructive pulmonary disorder (COPD) independently of tobacco use (Gracie & Hancox, 2021). Although not consistently demonstrated, there is a potential relationship between cannabis use and lung cancer (Campeny et al., 2020;Gracie & Hancox, 2021;. ...
The health effects of cannabis use may not always be seen as a high priority for Aboriginal and Torres Strait Islander communities. However, the impact of cannabis use on physical and mental health can have significant consequences. It is known that the use of high potency cannabis has increased over the last two decades, with a corresponding increased risk to health. In particular, young people are at increased risk of experiencing harms to mental health. Physical harms to health include effects on the respiratory system, cardiovascular system, an increased risk of cancer, and in-utero effects from maternal use. The review notes concern that in countries where there has been commercialisation of cannabis use, there has been an increase in the rate and use of high potency products. While generalising findings about cannabis use for Aboriginal and Torres Strait Islander people is problematic due to limited data, high rates of cannabis use have been found in some remote communities. The review highlights the protective factors that reduce harms from cannabis use and suggests future directions for a collaborative approach to addressing cannabis related harms in communities. This review is part of a suite of knowledge exchange products that includes a summary, a video, and a fact sheet.
... Study members represent the full range of socioeconomic status in the general population of the South Island of New Zealand and are primarily of New Zealand/European ethnicity. The cohort has been assessed at ages 3,5,7,9,11,13,15,18,21,26,32 and 38 years, and most recently at age 45 years, when we assessed 938 (94%) out of 997 surviving participants. Respiratory information, including asthma diagnoses, has been obtained at each assessment from 9 years onwards. ...
... Consistent with findings from an analysis of IOS measures at age 38 years and several studies of other lung function measures [11], cannabis had a different pattern of associations to tobacco. Among the pre-salbutamol IOS measures, lifetime history of tobacco smoking was only statistically associated with R 5 -R 20 (table 3), but tobacco smoking was associated with all post-salbutamol IOS measures when men and women were analysed together and several of the measures in each sex when they were analysed separately (supplementary tables S5 and S6). ...
... However, due to the difficulty of examining small airway pathology in humans and the confounding effects of tobacco use in many human studies, the exact mechanisms of cannabis effects on human small airways are unknown. Given that studies have consistently found that cannabis use is associated with large airway conductance (including among these participants) [11], it is surprising that R 20 (an IOS measure of central airway function) was not associated with cannabis in men. The reasons for this apparent discrepancy are unknown. ...
Background and objective
The long-term effects of cannabis on small airway function remain unclear. We investigated associations between cannabis use and small airway function in a general population sample.
Methods
Cannabis use was ascertained at multiple ages from age 18 to 45 years and quantified as joint-years among 895 participants in the Dunedin Multidisciplinary Health and Development Study. Small airway function at ages 38 and 45 years was measured using impulse oscillometry before and after inhalation of salbutamol. Analyses used multiple linear regression adjusting for tobacco use, body mass index, and height. Longitudinal analyses of cannabis use between 38 and 45 years also adjusted for IOS at age 38.
Results
Lifetime cannabis joint-years with IOS differed between men and women: in women, cannabis use was associated with pre-bronchodilator R5, R20, X5, AX, and Fres and marginally associated with R5-R20. Cannabis use was not statistically significantly associated with any of the pre-bronchodilator IOS measures in men. Cannabis use between ages 38 and 45 was associated with a similar pattern of changes in IOS measures. After salbutamol, cannabis use was only statistically significantly associated with R5 and R20 among women and none of the IOS measures among men.
Conclusions
Cannabis use is associated with small airway dysfunction at age 45 years, indicating an increase in peripheral airway resistance and reactance. These associations were greater and only statistically significant among women. Associations were weaker and mostly non-significant after bronchodilator use suggesting that cannabis-induced changes in small airways may be at least partially reversible.
... Toluolmissbrauch wird mit einem panlobulären Emphysem und dem Goodpasture-Syndrom Eindeutige Schlussfolgerungen für langfristige Folgen von Cannabiskonsum auf Lunge und Atemwege sind derzeit noch nicht möglich, da in den meisten Studien nicht zwischen den überlappenden Effekten des Tabak-und des Cannabiskonsums differenziert wurde. Die Karzinogene und respiratorischen Toxine in Cannabisund Tabakrauch sind zwar ähnlich, dennoch scheinen sich die Folgen des Cannabisrauchens von denen des Tabakrauchens zu unterscheiden [50,51]. So gilt die Entwicklung einer chronischen Bronchitis durch anhaltenden Cannabiskonsum mittlerweile zwar als fast gesichert [52], hinreichende Beweise, dass Cannabis COPD verursacht, fehlen aber [50]. ...
... Die Karzinogene und respiratorischen Toxine in Cannabisund Tabakrauch sind zwar ähnlich, dennoch scheinen sich die Folgen des Cannabisrauchens von denen des Tabakrauchens zu unterscheiden [50,51]. So gilt die Entwicklung einer chronischen Bronchitis durch anhaltenden Cannabiskonsum mittlerweile zwar als fast gesichert [52], hinreichende Beweise, dass Cannabis COPD verursacht, fehlen aber [50]. Auch allergische Reaktionen einschließlich Asthma sowie Assoziationen mit Lungenemphysem, Lungenkrebs und Pneumonien sind möglich, aber nicht eindeutig belegt [50,52]. ...
... So gilt die Entwicklung einer chronischen Bronchitis durch anhaltenden Cannabiskonsum mittlerweile zwar als fast gesichert [52], hinreichende Beweise, dass Cannabis COPD verursacht, fehlen aber [50]. Auch allergische Reaktionen einschließlich Asthma sowie Assoziationen mit Lungenemphysem, Lungenkrebs und Pneumonien sind möglich, aber nicht eindeutig belegt [50,52]. Zudem wurde in einigen Kasuistiken über Pneumothoraces, Pneumomediastinum sowie grobbullöse Lungenerkrankungen im Zusammenhang mit inhalativem Cannabiskonsum berichtet, jedoch auch hier ist der Zusammenhang nicht eindeutig bewiesen ( [52]; Tab. 2). ...
The use of inhaled psychotropic substances is widespread in our society. In addition to the wide variety of tobacco-containing smoking products, e‑cigarettes, cannabis, sniffing substances, cocaine and heroin are consumed by inhalation. While the harmful effects of most tobacco-containing smoking products on the lungs have been sufficiently researched, there is still a lack of scientifically sound evidence for many other substances consumed by inhalation. In particular, for novel products, such as e‑cigarettes and tobacco heaters, there is a lack of independent standardized data demonstrating reduced health risk as a result of lower exposure to harmful substances. Clear conclusions are also currently not possible for the long-term effects of cannabis use on the lungs and respiratory tract. For the inhaled use of cocaine and heroin, on the other hand, considerable damage to the lungs can be documented, especially in the case of extensive and chronic use.
... 13 U.S. rates of CUD are increasing, affecting 5.2% of adults in 2020. 54 Cannabis use disorder is associated with cardiovascular and respiratory diseases, 22,32 other substance use disorders (SUDs), 26 psychiatric conditions, 26 and psychosocial adversities including homelessness, legal problems, and interpersonal conflict. 23 Because of the increasing prevalence of chronic pain 44,66 and the perception that cannabis is an effective pain treatment, 36 understanding the risk for CUD among people with chronic pain has emerged as an important clinical issue. ...
... 46 It is important to consider chronic pain therapies other than cannabis use when its health risks outweigh the benefits, especially for patients with underlying cardiovascular or respiratory disease, for whom cannabis use can pose increased risks. 22,32 Pharmacologic therapies, such as gabapentinoids, acetaminophen, and nonsteroidal anti-inflammatory drugs, are effective treatments of nociceptive or neuropathic pain, although they are also associated with sedation, cognitive risks, and other adverse effects. 14,51 Nonpharmacologic therapies (eg, physical rehabilitation and cognitive-behavioral therapies [CBTs]) are recommended by the CDC and VHA as first-line alternatives to opioids for chronic pain, despite some barriers to their access. ...
In the United States, cannabis is increasingly used to manage chronic pain. Veterans Health Administration (VHA) patients are disproportionately affected by pain and may use cannabis for symptom management. Because cannabis use increases the risk of cannabis use disorders (CUDs), we examined time trends in CUD among VHA patients with and without chronic pain, and whether these trends differed by age. From VHA electronic health records from 2005 to 2019 (∼4.3-5.6 million patients yearly), we extracted diagnoses of CUD and chronic pain conditions (International Classification of Diseases [ICD]-9-CM, 2005-2014; ICD-10-CM, 2016-2019). Differential trends in CUD prevalence overall and age-stratified (<35, 35-64, or ≥65) were assessed by any chronic pain and number of pain conditions (0, 1, or ≥2). From 2005 to 2014, the prevalence of CUD among patients with any chronic pain increased significantly more (1.11%-2.56%) than those without pain (0.70%-1.26%). Cannabis use disorder prevalence increased significantly more among patients with chronic pain across all age groups and was highest among those with ≥2 pain conditions. From 2016 to 2019, CUD prevalence among patients age ≥65 with chronic pain increased significantly more (0.63%-1.01%) than those without chronic pain (0.28%-0.47%) and was highest among those with ≥2 pain conditions. Over time, CUD prevalence has increased more among VHA patients with chronic pain than other VHA patients, with the highest increase among those age ≥65. Clinicians should monitor symptoms of CUD among VHA patients and others with chronic pain who use cannabis, and consider noncannabis therapies, particularly because the effectiveness of cannabis for chronic pain management remains inconclusive.
... Few studies have found changes in lung function (FEV 1 / FVC) or emphysema in cannabis users although symptoms of chronic bronchitis (cough, sputum and wheeze) are noted [150]. There remains a lack of convincing data on the chronic cannabis smoke inhalation and development of alveolar damage [151] and remains equivocal owing in part to varying definitions of "joint years", variation in usage patterns between cannabis and tobacco smokers, changes in the size and strength of cannabis cigarettes ("joints") over time and control for concomitant tobacco use. [130,151,152]. ...
... There remains a lack of convincing data on the chronic cannabis smoke inhalation and development of alveolar damage [151] and remains equivocal owing in part to varying definitions of "joint years", variation in usage patterns between cannabis and tobacco smokers, changes in the size and strength of cannabis cigarettes ("joints") over time and control for concomitant tobacco use. [130,151,152]. There also remain a limited number of preclinical studies on cannabis smoke inhalation, with existing data supporting a link between chronic cannabis smoke and an emphysema-like phenotype [139]. ...
The lungs, in addition to participating in gas exchange, represent the first line of defense against inhaled pathogens and respiratory toxicants. Cells lining the airways and alveoli include epithelial cells and alveolar macrophages, the latter being resident innate immune cells important in surfactant recycling, protection against bacterial invasion and modulation of lung immune homeostasis. Environmental exposure to toxicants found in cigarette smoke, air pollution and cannabis can alter the number and function of immune cells in the lungs. Cannabis (marijuana) is a plant-derived product that is typically inhaled in the form of smoke from a joint. However, alternative delivery methods such as vaping, which heats the plant without combustion, are becoming more common. Cannabis use has increased in recent years, coinciding with more countries legalizing cannabis for both recreational and medicinal purposes. Cannabis may have numerous health benefits owing to the presence of cannabinoids that dampen immune function and therefore tame inflammation that is associated with chronic diseases such as arthritis. The health effects that could come with cannabis use remain poorly understood, particularly inhaled cannabis products that may directly impact the pulmonary immune system. Herein, we first describe the bioactive phytochemicals present in cannabis, with an emphasis on cannabinoids and their ability to interact with the endocannabinoid system. We also review the current state-of-knowledge as to how inhaled cannabis/cannabinoids can shape immune response in the lungs and discuss the potential consequences of altered pulmonary immunity. Overall, more research is needed to understand how cannabis inhalation shapes the pulmonary immune response to balance physiological and beneficial responses with potential deleterious consequences on the lungs.
... L'effet cumulatif des fumées de cannabis et de tabac sur le risque de BPCO est retrouvé dans la plupart des travaux [36] ; il est confirmé par une étude menée en médecine générale en Écosse [37]. ...
... Plusieurs revues systématiques rapportent des cas de bulles d'emphysème chez des fumeurs de cannabis [9,36,38]. ...
Résumé
Contrairement aux effets bien décrits de la fumée du tabac sur le poumon, les effets de la fumée de cannabis restent controversés ; le principal biais étant la consommation conjointe de tabac. La composition de la fumée d’un joint est proche de celle de la cigarette, contenant un grand nombre de composés cancérigènes et/ou altérant l’épithélium respiratoire. Les effets respiratoires démontrés chez les fumeurs chroniques de cannabis comportent une augmentation des symptômes de bronchite chronique, un effet cumulatif avec le tabac sur la survenue de BPCO et d’emphysème, un risque d’emphysème bulleux et de pneumothorax avec un risque plus important de récurrence après symphyse pleurale. Les travaux prospectifs récents retrouvent un impact négatif sur la fonction pulmonaire, avec une atteinte des voies aériennes mais aussi une altération de la DLCO et une baisse accélérée du VEMS. Enfin, fumer du cannabis est très fréquent parmi les jeunes patients atteints de cancer bronchique. Cette consommation pourrait conduire à un profil différent de cancer bronchique, potentiellement plus indifférencié et moins souvent accessible à une thérapie ciblée. L’interrogatoire sur la consommation de cannabis doit être systématique et une prise en charge spécifique doit être proposée.
... There were only a few reports declaring that the inhalation of marijuana smoke caused a damage to the pulmonary epithelial barrier and causing severe lung injury. [6][7][8] Since the diagnosis of acute inhalation injury is subjective and made on the basis of clinical findings, it is crucial to evaluate the patient and review the history, as well as to confirm the damage with an advanced imaging modality, such as HRCT. [9,10] In acute pulmonary responses, the lungs are primarily affected by the toxicity, as in the case of acute inhalation injury. ...
... [12] It is also claimed that different pattern of inhalation, higher temperatures of smoke compared to tobacco, and the unique breath-holding mechanism may alter the lung physiology and take a role in the cause of further epithelial injury and inflammation. [7] Recent case studies also have drawn attention to different spectrum of exposure injuries in the lungs. [6] However, none of the aforementioned studies investigated the aspects of acute inhalation injury as a result of marijuana smoking. ...
... L'effet cumulatif des fumées de cannabis et de tabac est retrouvé dans la plupart des travaux [10], il est confirmé par une étude menée en médecine générale en Écosse [11]. Des études complémentaires sont nécessaires, notamment celles incluant des gros fumeurs de cannabis et des fumeurs âgés. ...
... Plusieurs revues systématiques [10,13,14] retrouvent des rapports de cas de bulles d'emphysème chez des fumeurs de cannabis. Toutefois, les études épidémiologiques ne montrent pas de preuve en faveur d'une association entre usage de cannabis et emphysème pulmonaire. ...
Points essentiels
La relation entre cannabis et pathologies pulmonaires est difficile à établir : le cannabis est souvent fumé-mélangé à du tabac (« joint ») et les fumeurs de cannabis fument souvent aussi des cigarettes de tabac.
L’usage régulier de cannabis est un facteur de risque de bronchite chronique.
Il n’y a pas d’association significative entre inhalation de fumée de cannabis et obstruction bronchique, typique de la BPCO.
L’usage de cannabis peut augmenter le risque de sifflements thoraciques et/ou de développement d’un asthme.
L’usage régulier de cannabis est un facteur de risque de pneumopathies infectieuses, avec un risque plus élevé chez les sujets immunodéprimés et notamment les patients infectés par le VIH.
Les résultats des études épidémiologiques sur le risque de cancer bronchique chez les fumeurs de cannabis sont discordants.
Des cas de pneumothorax, pneumomédiastin, pneumopéricarde et pneumorachis ont été décrits chez les fumeurs de cannabis.
Les études épidémiologiques ne montrent pas d’association entre usage de cannabis et emphysème pulmonaire.
Les cannabinoïdes de synthèse, plus récemment introduits sur le marché, ont une toxicité importante. Ils peuvent provoquer des pneumopathies sévères et/ou une dépression respiratoire sévère.
... While smoking is an efficient way to deliver the active ingredients in cannabis, regular smoking is associated with increased respiratory symptoms (e.g., cough, wheeze) and risk of chronic bronchitis (the association between regular smoking cannabis and lung cancer is unproven). 9,21 Smoking is the dominant route of administration for many consumers who self-medicate with cannabis, including in New Zealand. 22 The inclusion of dry herb products in the legal MCS is seen as a way to facilitate the transitioning of existing consumers to the prescribed quality-controlled channel. ...
aim: To evaluate the implementation of the New Zealand Medicinal Cannabis Scheme (MCS), including how products, prices, prescribing and patient access have evolved since 2020. method: Analysis of administrative data obtained via Official Information Act (OIA) requests and publicly available information on products and prices. results: Six emerging trends were identified: 1) quarterly supply of medicinal cannabis products has increased fourteenfold since the implementation of the Scheme in early 2020, 2) most products are now THC-dominant rather than CBD, 3) most products are in the form of dried cannabis flower rather than oral liquids/oils, 4) prices of products have declined to be comparable to the illegal market, 5) specialised private cannabis clinics have expanded patient access, and 6) inequities persist due to expense, and disproportionately affect Māori and those on lower incomes. conclusions: The New Zealand MCS successfully established a domestic medicinal cannabis production sector, reduced prices and expanded the range of products to provide alternatives to illegal supply. It has also inadvertently created the conditions for the emergence of specialised cannabis clinics that have enhanced access. However, the increasing supply of THC-dominant and flower products, and the privatisation of prescribing via cannabis clinics, may have unintended negative consequences.
... Additionally, substances are processed by distinct organs aside from the CNS. For example, alcohol use disorder primarily damages the liver while cannabis use disorder can induce bronchitis in the lungs (Gracie & Hancox, 2021;Leggio & Lee, 2017). By adapting response MPRA to an in vivo model, we will have the capability of truly understanding how substances or other environmental toxins impact genetic regulation and potentially contribute to disease progression. ...
The human genome is largely noncoding, yet the field is still grasping to understand how noncoding variants impact transcription and contribute to disease etiology. The massively parallel reporter assay (MPRA) has been employed to characterize the function of noncoding variants at unprecedented scales, but its application has been largely limited by the in vitro context. The field will benefit from establishing a systemic platform to study noncoding variant function across multiple tissue types under physiologically relevant conditions. However, to date, MPRA has been applied to only a handful of in vivo conditions. Given the complexity of the central nervous system and its widespread interactions with all other organ systems, our understanding of neuropsychiatric disorder-associated noncoding variants would be greatly advanced by studying their functional impact in the intact brain. In this review, we discuss the importance, technical considerations, and future applications of implementing MPRA in the in vivo space with the focus on neuropsychiatric disorders.
... THC can exacerbate existing psychological disorders like anxiety, depression, and schizophrenia, potentially leading to more severe psychotic episodes. 42 Tobacco smokers who also consume Cannabis face an increased risk of lung diseases, including lung cancer and chronic obstructive pulmonary disease. The current medical prohibition on Cannabis hinders the accurate assessment of its risk potential in diseases caused by tobacco use. ...
Cannabinoids' therapeutic potential has garnered significant attention worldwide, with studies displaying their remarkable effectiveness in treating a variety of ailments. These compounds are known for their anti-inflammatory and neuroprotective properties, leading to investigations into their antipsychotic, anxiolytic, and anticonvulsant properties. This narrative review aims to provide an up-to-date overview of the primary therapeutic applications of cannabinoids and their outcomes. We conducted an extensive search across three databases: PubMed, Google Scholar, and Scopus, selecting relevant materials following the PRISMA 2020 guidelines for systematic reviews, while recognizing that this review adopts a narrative approach. Cannabis, a plant with psychotropic attributes, has been subject to strict legal restrictions since the early 20th century, rooted in religious, socio-cultural, and political principles. Nevertheless, cannabinoids derived from the plant offer substantial therapeutic potential, particularly as adjuncts in pain management. Moreover, their efficacy has been demonstrated in various conditions, including respiratory, metabolic, immunological, and neurodegenerative disorders like Parkinson's and Alzheimer's. Recognizing the significance of the Cannabis plant in scientific research is crucial, as it paves the way for safer therapeutic alternatives with minimal side effects. Therefore, facilitating and prioritizing its study across various medical disciplines is essential.
... SP is characterized by the occurrence of pneumothorax without traumatic or iatrogenic causes, leading to air accumulation in the pleural cavity. Factors increasing the risk of primary spontaneous pneumothorax (PSP) include a lean, tall physique, exposure to air pollution, smoking, and marijuana use (4)(5)(6)(7). Additionally, secondary spontaneous pneumothorax (SSP) results from underlying pulmonary conditions like pulmonary tuberculosis, malignancies, and chronic obstructive pulmonary disease (COPD) (3). ...
... The route of drug use has an impact on the harms caused. Smoking cannabis is associated with changes in lung function, but unlike tobacco it appears to increase the risk of severe bronchitis at quite low exposure but not lead to chronic obstructive pulmonary disease (18). Inhaling cocaine predisposes users to infection of the upper respiratory tract, including sinusitis and septal abscesses. ...
Human beings have prepared and used psychoactive substances for thousands of years. Alcohol was produced by the earliest civilizations and has played some part in most cultures throughout history. Other psychoactive substances have been extracted from local vegetation for specific reasons. For example, hill farmers working at high altitude in Peru began to chew coca leaves for their stimulant effects, the Ancient Greeks used opium poppy extracts in medical poultices, and the hallucinogenic effects of mescaline from the peyote cactus became part of religious ceremonies of indigenous people in Mexico. Technological advances have meant that some substances have become more readily accessible, and so their associated harms have become more apparent. Humankind’s relationship with these substances has always generated strong emotions, both for and against, and there has been a concerted drive by the wealthiest countries to prohibit the use of many psychoactive substances (‘illicit drugs’) whilst promoting others (alcohol). Although the use of particular substances tends to wax and wane, it is important to see this in the wider historical context, as use of psychoactive drugs has increased every decade since the Second World War. More importantly, people’s first introduction to drugs occurs at a younger age, and this is important because earlier use is associated with an increased risk of developing significant problems.
Of importance to the psychiatrist, a proportion of individuals develop an ‘addiction’ to these psychoactive substances whereby their ability to control the frequency and extent of their consumption becomes eroded. Psychoactive substance use occurs across a wide spectrum, from occasional social use, through use that starts to cause biological, psychological and social problems, to dependence. Dependence can be thought of as the iceberg visible above the water, with a much larger potential issue lurking below the waterline. Alcohol consumption is directly or indirectly associated with many health conditions, and 5.3% of all global deaths in 2016 were estimated to be attributable to alcohol, a greater cause of mortality than that caused by diseases such as diabetes, tuberculosis, and HIV/AIDS. Illicit drug use has much in common with use of legal substances such as tobacco and alcohol, but the illegality of drug use adds new problems such as the risk of legal sanctions. Although the neurobiological and psychological understanding of addiction has increased dramatically in the past 30 years, substance use disorders remain a heavily stigmatised problem.
All healthcare professionals should be able to take a basic history and signpost the individual with a substance use disorder towards help and support. The medical perspective on this issue is just one of many, and effective responses to people who struggle with the use of psychoactive substances incorporate a wide range of interpersonal, familial, community and societal strategies. This chapter will focus on the broad principles of assessment and diagnosis and will outline the current structure of specialist treatment services and the interventions that they deliver.
... Only two investigations evaluated HRCT pictures obtained from cannabis consumers in depth. 10 Within the scope of this investigation, the usage of chest CT in cannabis smokers was investigated.. ...
Introduction: In contrast, cannabinoids and nicotine are chemically distinct compounds, with cannabinoids exhibiting a unique set of effects pertaining to aspects such as gene expression, inflammatory mechanisms, immunological modulation, and cellular energy and survival. Consequently, a comparison between the pulmonary effects of cannabis and tobacco consumption is crucial. As a sensitive and repeatable tool for quantifying the airway alterations and alveolar lung damage that are hallmarks of smoking-related emphysema and COPD, noninvasive lung imaging with HRCT scans has developed. In-depth analyses of HRCT images obtained from cannabis consumers were conducted in only two studies. The aim: This study review chest CT findings in cannabis smokers. Methods: For this systematic review, publications that were published from 2012 to 2023 were taken into account during the search process. This was achieved through the utilization of numerous online reference sources, such as Pubmed and SagePub. The decision was made to exclude review articles, previously published works, and incomplete works. Result: We obtained 54 articles from Pubmed and 76 from SagePub. We extracted were 2 article from Pubmed and 4 articles from SagePub. Conclusion: Research shows that patients can experience pneumothorax with bullae and blebs. Those who smoke marijuana can also experience emphysema and chronic bronchitis.
... The effect of cannabis use on the occurence of COPD has not been fully demonstrated ; however, the cumulative effect of cannabis and tobacco smoke inhalation on COPD is found in most studies [47]. Aldington et al. [8] were able to estimate from a study of subjects classified into four groups : cannabis-only smokers, mixed smokers, tobacco-only smokers and non-smokers that, in terms of bronchial obstruction, one joint had the effect of 2.5 to 5 cigarettes. ...
Objectives : Tobacco and cannabis are the most used inhaled drugs worldwide. This review looked at the effects of their combined use, the dependence induced, and the ways of helping people to quit.
Method. Medline was searched using the keywords « tobacco smoking » or « cannabis use » or « tobacco marijuana co-use » and « health effects » or « dependence » or " « smoking cessation intervention » with « Title/Abstract » limits and search period from 1980 to 2023. A selection of articles in English or in French was analyzed.
Results. Combustion smoke from tobacco and cannabis is more toxic than of tobaccoorcannabis, induced dependence is more elevated, tobacco and cannabis cessation is moredifficult than quitting tobacco or cannabis alone.
Conclusion. The marketing of cannabis with a high active ingredient content, the availabilityof synthetic forms and the increasing legalization of recreational use, against a backdropof aslow decline in the prevalence of smoking, is leading to the danger of an increase inthecombined use of tobacco and cannabis ; this risk should be a concern for all health authoritiesand professionnals
... Evidence does support that cannabis smoke exposure is associated with cough, wheeze, sputum production and dyspnea (Ghasemiesfe et al. 2018). Smoking cannabis may also increase the risk of severe bronchitis, although there is conflicting evidence that this leads to chronic obstructive pulmonary disease (COPD), an obstructive lung disease known to be caused by tobacco smoke and other inhaled pollutants (Gracie and Hancox 2021). Cannabis smoke may also affect physical (e.g., mucociliary clearance) and immunological defense mechanisms (Chatkin et al. 2017). ...
Cannabis contains cannabinoids including Δ⁹-tetrahydrocannabinol (THC) and cannabidiol (CBD). THC causes the psychoactive effects of cannabis, and both THC and CBD are thought to be anti-inflammatory. Cannabis is typically consumed by inhaling smoke that contains thousands of combustion products that may damage the lungs. However, the relationship between cannabis smoke exposure and alterations in respiratory health is poorly defined. To address this gap in knowledge, we first developed a mouse model of cannabis smoke exposure using a nose-only rodent inhalation exposure system. We then tested the acute effects of two dried cannabis products that differ substantially in their THC–CBD ratio: Indica-THC dominant (I-THC; 16–22% THC) and Sativa-CBD dominant (S-CBD; 13–19% CBD). We demonstrate that this smoke exposure regime not only delivers physiologically relevant levels of THC to the bloodstream, but that acute inhalation of cannabis smoke modulates the pulmonary immune response. Cannabis smoke decreased the percentage of lung alveolar macrophages but increased lung interstitial macrophages (IMs). There was also a decrease in lung dendritic cells as well as Ly6Cintermediate and Ly6Clow monocytes, but an increase in lung neutrophils and CD8⁺ T cells. These immune cell changes were paralleled with changes in several immune mediators. These immunological modifications were more pronounced when mice were exposed to S-CBD compared to the I-THC variety. Thus, we show that acute cannabis smoke differentially affects lung immunity based on the THC:CBD ratio, thereby providing a foundation to further explore the effect of chronic cannabis smoke exposures on pulmonary health.
... This varies widely and appears disconnected from real-world cannabis use. For example, so-called heavy cannabis users include people smoking more than five joints a day (Yücel et al., 2008), consuming cannabis ten times a month (Cousijn et al., 2011), 500 times a year (Pope and Yurgelun-Todd, 1996), daily for 2 years (Degenhardt et al., 2003), or a joint a day for more than 20 years (Gracie and Hancox, 2021). Another problem is how to define "occasional users" for the purposes of comparison. ...
Despite growing evidence to the contrary, researchers continue to posit causal links between cannabis, crime, psychosis, and violence. These spurious connections are rooted in history and fueled decades of structural limitations that shaped how researchers studied cannabis. Until recently, research in this area was explicitly funded to link cannabis use and harm and ignore any potential benefits. Post-prohibition cannabis research has failed to replicate the dire findings of the past. This article outlines how the history of controlling cannabis research has led to various harms, injustices, and ethical complications. We compare commonly cited research from both the prohibition and post-prohibition eras and argue that many popular claims about the dangers of cannabis are the result of ethical lapses by researchers, journals, and funders. We propose researchers in this area adopt a duty of care in cannabis research going forward. This would oblige individual researchers to establish robust research designs, employ careful analytic strategies, and acknowledge limitations in more detail. This duty involves the institutional recognition by funders, journals, and others that cannabis research has been deliberately misconstrued to criminalize, stigmatize, and pathologize.
... Other studies in humans report that cannabis use by inhalation is associated with symptoms of chronic bronchitis and airway inflammation, particularly with heavy use [57]. However, there is conflicting evidence of an association between cannabis use and the development of chronic obstructive pulmonary disease [58,59]. It should be noted that the changes in respiratory functions associated with chronically smoked cannabis are difficult to dissociate from those caused by tobacco alone because of consumption habits that include tobacco [60]. ...
Objectives:
To date, very few cannabis-based specialities are authorised on the French market despite a growing demand from patients and health professionals. The objective of this study is to review the tolerance profile and the French legislative status of the two main cannabinoids used for therapeutic purposes: tetrahydrocannabiol (THC) associated with psychoactive effects and non-psychoactive cannabidiol (CBD).
Methods:
This review is based on relevant articles retrieved by a search in Google Scholar and PubMed databases and on an assessment of the legal texts and summaries of product characteristics available in France.
Results:
Evidence for the tolerability of CBD during chronic use is reassuring, but a significant risk of drug interactions exists. THC use appears to be associated with a higher proportion of serious adverse effects, including neuropsychological and cardiovascular effects. Inhaled cannabis appears to be associated with greater toxicity than the oral route. These data are presented together with the pharmacokinetic and pharmacodynamic data of THC and CBD.
Conclusion:
The literature reports several frequent but rarely serious adverse effects of CBD during chronic use as well as a significant risk of drug interactions. THC use seems to be associated with a higher proportion of serious adverse effects compared to CBD, particularly at the neuropsychological and cardiovascular levels. Health professionals should be up to date on the particularities of therapeutic cannabis in terms of efficacy, safety and drug interactions.
... Despite the economic benefits of legalization and or decreased incidence. Gracie and Hancox similarly examined pulmonary effects of cannabis smoking through reviewing meta-analysis observational studies as well as cross-sectional studies [15]. The metaanalysis demonstrated that cannabis smokers were twice as likely to develop cough and four times as likely to develop sputum production when compared to nonsmokers. ...
... It is important to note that the inhalation method of cannabis delivery may carry increased risks of oral disease, with research indicating that smoking cannabis risks cancer of oral mucosa, dental caries, periodontal disease and oral infections [109]. The effects of cannabis use on lung disease are difficult to analyse due to variability in method of inhalation and concurrent tobacco use; however, evidence does show that cannabis smoke leads to bronchitis and bullous lung disease with a greater risk of pneumothorax [110]. ...
Dysmenorrhoea effects up to 90% of women of reproductive age, with medical management options including over-the-counter analgesia or hormonal contraception. There has been a recent surge in medicinal cannabis research and its analgesic properties. This paper aims to critically investigate the current research of medicinal cannabis for pain relief and to discuss its potential application to treat dysmenorrhoea. Relevant keywords, including medicinal cannabis, pain, cannabinoids, tetrahydrocannabinol, dysmenorrhoea, and clinical trial, have been searched in the PubMed, EMBASE, MEDLINE, Google Scholar, Cochrane Library (Wiley) databases and a clinical trial website (clinicaltrials.gov). To identify the relevant studies for this paper, 84 papers were reviewed and 20 were discarded as irrelevant. This review critically evaluated cannabis-based medicines and their mechanism and properties in relation to pain relief. It also tabulated all clinical trials carried out investigating medicinal cannabis for pain relief and highlighted the side effects. In addition, the safety and toxicology of medicinal cannabis and barriers to use are highlighted. Two-thirds of the clinical trials summarised confirmed positive analgesic outcomes, with major side effects reported as nausea, drowsiness, and dry mouth. In conclusion, medicinal cannabis has promising applications in the management of dysmenorrhoea. The global medical cannabis market size was valued at USD 11.0 billion in 2021 and is expected to expand at a compound annual growth rate (CAGR) of 21.06% from 2022 to 2030. This will encourage academic as well as the pharmaceutical and medical device industries to study the application of medical cannabis in unmet clinical disorders.
... The use of marijuana causes repercussions on the respiratory system, such as dyspnea, cough and sputum production (14) . These events, associated with the respiratory and pulmonary effects resulting from SARS-CoV-2 infection, provide a higher risk of complications of the clinical picture (15)(16) . ...
Objective:
to identify and synthesize studies on the effects of cannabis use and its relation with SARS-CoV-2, as well as the therapeutic possibilities of using cannabinoids in the prevention and treatment of COVID-19.
Methods:
scoping review, in the BVS, PubMed, SCIELO, CINAHL, SCOPUS, Web of Science, MedNar, CAPES and ProQuest databases, with no language restriction and year limitation. Narrative synthesis was performed.
Results:
cannabis use causes changes in the respiratory and vascular system, it reduces the production of cytokines, which affects the users' immune system, increasing the susceptibility to infection and progression of COVID-19. However, studies have suggested the use of cannabinoids in the prophylaxis and treatment of COVID-19, due to their anti-inflammatory effect.
Conclusions:
the use of inhaled cannabis increases the progression and severity of the infection. On the other hand, the benefits of cannabinoids seem promising to modulate the immune system, but it needs further studies.
... Patients with a cannabis diagnosis in our study had higher rates of respiratory symptoms (59% vs 38%) and COPD (27% vs 15%) compared to matched controls, but these differences were not statistically significant. Past work generally supports a link between cannabis and bronchitis, but less commonly for cannabis and serious respiratory conditions such as COPD (Gracie and Hancox, 2021;National Academies of Sciences and Medicine, 2017). One limitation associated with past work is that studies have not consistently controlled for tobacco smoking in analyses, making it difficult to separate out the effects (National Academies of Sciences and Medicine, 2017). ...
Background
Research on cannabis-related health outcomes in diverse older adults is limited. The current study utilized a matched cohort study design to compare older adults in Hawai’i with identified cannabis diagnoses and matched controls on chronic health conditions, acute health events, and healthcare utilization from 2016-2020.
Method
Patients age 50+ were identified using ICD-10 diagnostic codes for cannabis use, abuse, and dependence using electronic health record data from an integrated health system (Kaiser Permanente Hawai’i). Those with cannabis diagnoses (n=275) were compared to matched non-using controls (n=275; based on age, sex) on chronic health conditions (coronary heart disease, hypertension, COPD, chronic non-cancer pain), acute health events (myocardial infarction, respiratory symptoms, stroke, persistent or cyclic vomiting, injuries), and healthcare utilization (outpatient, inpatient, and emergency department visits) following case identification for two years.
Results
Participants were 19.3% Native Hawaiian/Pacific Islander, 24.4% Asian, 47.8% White, and 8.5% Other/Unknown, with an average age of 62.8 years (SD=7.3). Adjusting for covariates as possible, participants with a cannabis diagnosis had significantly greater risk of coronary heart disease, chronic non-cancer pain, stroke, myocardial infarction, cyclic vomiting, and injuries, over time, compared to controls. Cannabis use was associated with any and greater frequency of outpatient, inpatient, and emergency department visits.
Conclusions
In a diverse sample, older adults who used cannabis had worse health conditions and events and used more health services over a two-year period. Future studies should evaluate cannabis-related health outcomes, effects of cannabis problem severity, as well as implications for healthcare in aging populations.
... All vaporization systems analyzed in this report were below temperatures reached in a cigarette during a puff (850-920˚C) and below that of a cannabis "joint" which is hypothesized to burn hotter than tobacco cigarettes [22,23]. Importantly, the temperature-controlled system was able to generate a wide range of temperatures that included much lower coil temperatures than either of the voltage-controlled 510 systems included in this study. ...
Vaporized cannabis is believed to be safer than smoking, but when heated to excessive temperatures nearing combustion (>900 °C) harmful byproducts may form. While some cannabis extract vaporizers operate well below these high temperatures, heating coil temperatures obtained during actual use are frequently not reported and many operate at high temperatures. We report on two major objectives: 1) development of an infrared thermography method to measure heating coil temperatures in cannabis extract vaporizers during a simulated puff and 2) a comparison of temperature- to voltage- controlled cannabis extract vaporization systems during a puff. Infrared thermography was used to measure heating coil temperatures in one temperature-controlled and two voltage-controlled systems. The cartridges were modified for direct line-of-sight on the heating coils, the wick and coils were saturated with cannabis extract, and fixtures were developed to force two liters per minute air flow past the coils for the full duration of the puff allowed by the device. The voltage-controlled systems produced higher temperatures with greater variability than the temperature-controlled system. At the highest temperature setting (420 °C) the temperature-controlled system reached an average heating coil temperature of 420 ± 9.5 °C whereas the 4.0V setting on the variable voltage system reached an average temperature of 543 ± 95.9 °C and the single voltage (3.2V) system an average of 450 ± 60.8 °C. The average temperature at the lowest setting (270 °C) on the temperature-controlled system was 246 ± 5.1 °C and the variable voltage system (2.4V) was 443 ± 56.1 °C. Voltage alone was a poor indicator of coil temperature and only the temperature-controlled system consistently maintained temperatures less than 400 °C for the full puff duration. These lower temperatures could reduce the likelihood of harmful thermal degradation products and thus may reduce potential health risk to consumers when vaporizing cannabis extracts.
... However, in many countries, Cannabis is still prohibited [7]. In Belgium, this psychodysleptic drug is mainly cultivated indoors and is commonly seized by law enforcement. ...
Cannabis sativa L. is widely used as recreational illegal drugs. Illicit Cannabis profiling, comparing seized samples, is challenging due to natural Cannabis heterogeneity. The aim of this study was to use GC–FID and GC–MS herbal fingerprints for intra (within)- and inter (between)-location variability evaluation. This study focused on finding an acceptable threshold to link seized samples. Through Pearson correlation-coefficient calculations between intra-location samples, ‘linked’ thresholds were derived using 95% and 99% confidence limits. False negative (FN) and false positive (FP) error rate calculations, aiming at obtaining the lowest possible FP value, were performed for different data pre-treatments. Fingerprint-alignment parameters were optimized using Automated Correlation-Optimized Warping (ACOW) or Design of Experiments (DoE), which presented similar results. Hence, ACOW data, as reference, showed 54% and 65% FP values (95 and 99% confidence, respectively). An additional fourth root normalization pre-treatment provided the best results for both the GC–FID and GC–MS datasets. For GC–FID, which showed the best improved FP error rate, 54 and 65% FP for the reference data decreased to 24 and 32%, respectively, after fourth root transformation. Cross-validation showed FP values similar as the entire calibration set, indicating the representativeness of the thresholds. A noteworthy improvement in discrimination between seized Cannabis samples could be concluded.
... The effect on the respiratory system is confirmed by symptoms, and various studies have been conducted in Cannabis smokers. The surveys conducted revealed that cough, sputum production, and wheezing are present in a 3:5 ratio among those who smoke Cannabis (Abdallah et al., 2018;Gracie and Hancox, 2020). Smoking Cannabis and tobacco has been found to cause bronchial impairment and increases the chances of basal cell hyperplasia, disorientation among cells, alteration of nuclei, and even increases the value of the nuclear/cytoplasmic ratio (Tashkin, 2013). ...
Cannabis sativa, widely known as ‘Marijuana’ poses a dilemma for being a blend of both good and bad medicinal effects. The historical use of Cannabis for both medicinal and recreational purposes suggests it to be a friendly plant. However, whether the misuse of Cannabis and the cannabinoids derived from it can hamper normal body physiology is a focus of ongoing research. On the one hand, there is enough evidence to suggest that misuse of marijuana can cause deleterious effects on various organs like the lungs, immune system, cardiovascular system, etc. and also influence fertility and cause teratogenic effects. However, on the other hand, marijuana has been found to offer a magical cure for anorexia, chronic pain, muscle spasticity, nausea, and disturbed sleep. Indeed, most recently, the United Nations has given its verdict in favour of Cannabis declaring it as a non-dangerous narcotic. This review provides insights into the various health effects of Cannabis and its specialized metabolites and indicates how wise steps can be taken to promote good use and prevent misuse of the metabolites derived from this plant.
... Recently, we read the article titled "Cannabis Use Disorder and the Lungs" by Gracie and Hancox published in Addiction in 2021 (1). As pulmonologists, we found this manuscript to be relevant in raising awareness on a subject that needs further investigative efforts, namely the question of cannabis usage via inhalation and its effects on the lungs. ...
... This is an important observation, because development of nicotine dependence symptoms has been observed in occasional (light and intermittent) smokers who do not smoke tobacco daily [16,36]. Co-administration of cannabis and tobacco is not necessarily more acutely rewarding [37,38], but it produces more negative acute cardiovascular effects [38] and is associated with chronic bronchitis, even at low exposure [39]. Co-administration is also associated with higher risk of dependence and poorer psychosocial outcomes [40,41]. ...
Background and aims
In Great Britain, cannabis and tobacco are commonly used substances, both independently and together. Use of either substance is associated with mental health problems, but prevalence of co‐use within these populations is unknown. We aimed to 1) estimate prevalence of cannabis use, frequency of use and routes of administration (ROA) among tobacco smokers and non‐smokers and 2) investigate mental health problems amongst non‐users, tobacco‐only, cannabis‐only and co‐users of both substances.
Design
Cross‐sectional national online survey (Action on Smoking and Health) fielded in February–March 2020.
Setting
Great Britain
Participants
Adults in Great Britain aged ≥ 18 year (n = 12,809)
Measurements
Tobacco use status (smoker [daily or non‐daily] or non‐smoker [never or ex‐smoker]), cannabis use frequency (never to daily), detailed ROAs of cannabis, self‐reported treatment for mental health disorders (depression, anxiety, and any). Statistically weighted prevalence estimates were computed to ensure representativeness. Correlates were assessed using chi‐squared tests and logistic regression.
Findings
In Great Britain in 2020, 7.1% of the sample had used cannabis in the past year. Tobacco smokers had greater odds of using cannabis in the past year (21.9%) and using cannabis daily (8.7%) than non‐smokers (past‐year: 4.7%; aOR=10.07, [95% CI: 8.4‐12.0]; daily: 0.7%; aOR=24.6, [95% CI: 17.96‐35.55]). Co‐administration with tobacco was common (46.2% of non‐smokers, 80.8% of tobacco smokers). Co‐users reported the highest prevalence of any treatment for mental health problems (54.2%) in comparison to cannabis‐only (45.8%), tobacco‐only (33.2%) and non‐users (22.7%; all p≤0.05).
Conclusion
Approximately one in 13 adults in Great Britain reports having used cannabis in the past year, approximately four times as many among cigarette smokers as non‐smokers. Co‐administration of cannabis and tobacco, via smoking, appears to be common, including among self‐identified non‐smokers. Mental health problems appear to be particularly common among dual users.
... Due to challenges in conducting epidemiological research (e.g. because of the legal status of cannabis and that most cannabis users worldwide also smoke tobacco), the adverse physical health effects of cannabis remain largely uncertain (2). One consistent finding has been an association between heavy, long-term use of cannabis and respiratory problems such as chronic bronchitis (10,11). Limited evidence suggests cannabis use may elevate risk of cardiovascular disease (12,13) and possibly testicular cancer (14). ...
Legalization and commercial sale of non-medical cannabis has led to increasing diversity and potency of cannabis products. Some of the American states that were the first to legalize have seen rises in acute harms associated with cannabis use, e.g. Colorado has seen increases in emergency department visits for cannabis-related acute psychological distress and severe vomiting (hyperemesis), as well as a number of high-profile deaths related to ingestion of high doses of cannabis edibles. Over-ingestion of cannabis is related to multiple factors, including the sale of cannabis products with high levels of THC and consumers’ confusion regarding labelling of cannabis products, which disproportionately impact new or inexperienced users. Based on our review of the literature, we propose three approaches to minimizing acute harms: early restriction of cannabis edibles and high-potency products; clear and consistent labelling that communicates dose/serving size and health risks; and implementation of robust data collection frameworks to monitor harms, broken down by cannabis product type (e.g. dose, potency, route of administration) and consumer characteristics (e.g. age, sex, gender, ethnicity). Ongoing data collection and monitoring of harms in jurisdictions that have existing legal cannabis laws will be vital to understanding the impact of cannabis legalization and maximizing public health benefits.
... The effects of chronic cannabis smoking on respiratory health have not yet been clearly established, but there is sufficient evidence that these are not good. 3 It seems incongruous for a country that aspires to eliminating tobacco smoking in the next 5 years (a goal that we are unlikely to achieve 4 ) to be considering introducing a second smoked substance. 2020 is not over yet! ...
Cannabis use is increasingly common among patients presenting for medical care. Its implications for intensive care unit (ICU) management remain unclear. Cannabis has widespread downstream effects on nearly all organ systems, some of which are directly applicable to ICU providers. The relatively limited scientific knowledge and vast number of active compounds in botanical cannabis emphasize the need for further research to better identify and characterize their impact on intensive care management. Here, we review available preclinical and clinical evidence that may impact intensive care management of patients with acute or chronic adverse effects of cannabis usage.
BACKGROUND
Increasing legalization and widespread misinformation about the dangers of cannabis use have contributed to the rising prevalence of cannabis use disorder (CUD) among adolescents. Our objective was to determine the prevalence of CUD in adolescent surgical patients and evaluate its association with postoperative complications.
METHODS
We performed a retrospective, 1:1 propensity-matched cohort study of adolescents (aged 10–17 years) with and without CUD who underwent inpatient operations at US hospitals participating in the Pediatric Health Information System from 2009 to 2022. The primary outcome was the trend in prevalence of CUD. Secondary outcomes included postoperative complications. Using a Bonferroni correction, we considered a P value < .008 to be significant.
RESULTS
Of 558 721 adolescents undergoing inpatient surgery from 2009 to 2022, 2604 (0.5%) were diagnosed with CUD (2483 were propensity matched). The prevalence of CUD increased from 0.4% in 2009 to 0.6% in 2022 (P < .001). The adjusted odds of respiratory complications, ICU admission, mechanical ventilation, and extended hospital stay were significantly higher in adolescents with CUD (respiratory complications: odds ratio [OR], 1.52; 95% confidence interval [CI], 1.16–2.00; P = .002; ICU admission: OR, 1.78; 95% CI, 1.61–1.98; P < .001; mechanical ventilation: OR, 2.41; 95% CI, 2.10–2.77; P < .001; extended hospital stay: OR, 1.96; 95% CI, 1.74–2.20; P < .001). The propensity score-adjusted odds of postoperative mortality or stroke for adolescents with CUD were not significantly increased (mortality: OR, 1.40; 95% CI, 0.87–2.25; P = .168; stroke: OR, 2.46; 95% CI, 1.13–5.36; P = .024).
CONCLUSIONS
CUD is increasing among adolescents scheduled for surgery. Given its association with postoperative complications, it is crucial to screen adolescents for cannabis use to allow timely counseling and perioperative risk mitigation.
Problems relating to alcohol or drugs occur across a spectrum of levels of consumption and may be physical, psychological or social in nature. At one extreme, there is a small but significant proportion of people who develop dependence and may require both intensive and extensive support. However, on a population level, huge reductions in the harm caused by psychoactive substances could be made if everyone was encouraged to use a bit less. All health and social care professionals should be able to screen for potential alcohol use disorders, deliver brief advice and refer on to specialist services where appropriate. They should also have an awareness of the common illicit drugs and the potential problems these drugs are associated with. The evidence base for treatment of substance use disorders has developed over the past 30 years, and clinicians should be positive and optimistic that meaningful change in behaviour can be achieved. Prompt referral to the right level of support and treatment may prevent future problems. Recovery support services play a crucial part in sustaining any gains made in treatment, and many people recover without using professionally directed treatment at all. It is estimated that approximately 10 per cent of the population of the USA is in remission from a substance use disorder of any severity.
BACKGROUND
Cannabis is a widely used illicit drug with effects on different pain pathways. However, interactions between cannabis and postoperative pain are unclear. Cannabis smoking also affects the lungs, but the impact of cannabis use on postoperative pulmonary complications is unknown. We hypothesized that preoperative cannabis use in adults having elective surgery is associated with higher postoperative opioid consumption. Secondarily, we tested the hypothesis that cannabis use is associated with higher pain scores, hypoxemia (oxygen saturation [Sp o 2 ]/fraction of inspired oxygen [F io 2 ] ratio), and higher postoperative pulmonary complications compared to nonuse of cannabis.
METHODS
In this retrospective study, we included adult patients who had elective surgeries at Cleveland Clinic Main Campus between January 2010 and December 2020. The exposure was use of cannabis within 30 days before surgery, and the control group never used cannabis. Patients who had regional anesthesia or chronic pain diagnosis were excluded. The primary outcome was postoperative opioid consumption; 3 secondary outcomes were time-weighted average (TWA) postoperative pain score, TWA Sp o 2 /F io 2 ratio, and composite of pulmonary complications after surgery. We assessed the association between cannabis use and opioid consumption during the first 24 postoperative hours using linear regression on log-transformed opioid consumption with a propensity score–based method (inverse probability of treatment weighting [IPTW]) adjusting for confounders. We further adjusted for imbalanced confounding variables after IPTW was applied.
RESULTS
In total, 1683 of 34,521 patients were identified as cannabis users. Cannabis use was associated with increased opioid consumption, with an adjusted ratio of geometric means (95% confidence interval [CI]) of 1.30 (1.22–1.38; P < .0001) for cannabis users versus nonusers. Secondarily, (1) cannabis use was associated with increased TWA pain score, with a difference in means of 0.57 (95% CI, 0.46–0.67; P < .0001); (2) cannabis use was not associated with TWA Sp o 2 /F io 2 , with an adjusted difference in means of 0.5 (95% CI, −3.1 to 4.2; P = .76); and (3) cannabis use was not associated with a collapsed composite of pulmonary complications, with estimated odds ratio of 0.90 (95% CI, 0.71–1.13; P = .34).
CONCLUSIONS
Adult cannabis users undergoing surgeries were found to have significantly higher postoperative opioid consumption and pain scores than nonusers. Cannabis use did not have a clinically meaningful association with hypoxia or composite pulmonary complications.
The prevalence of cannabis usage is increasing worldwide, including among both Indigenous and non-Indigenous Australians. The long-term effects of cannabis use on the lungs are well-known. However, the acute adverse effects on the lungs are sparsely reported. There are different ways in which cannabis can be inhaled, such as smoking or through a water vaporizing method known as a “bong.” An improvised innovative bong device that is commonly used in Northern Australia, called a “bucket bong,” uses water and air pressure to assist in cannabis inhalation. In this report, we describe three patients from remote and rural Northern Australian communities presenting with near–life-threatening events (acute pneumonitis and massive pneumothorax) immediately after the use of cannabis via bucket bong.
Résumé
Objectives
Recreational cannabis use was legalized in Canada in 2018. There is minimal research assessing family physicians’ abilities to address recreational cannabis use with patients.
We sought to assess family physician's knowledge and practice of screening and counseling patients on legalized recreational cannabis consumption.
Methods
Family physicians in Saskatchewan were invited to complete a cross-sectional survey, distributed by the Saskatchewan Medical Association, in January to February 2020. The survey captured family physicians’ knowledge of recreational cannabis counseling practices and continued training needs.
Results
Eighty-two surveys were completed (10% response rate). Ninety-three percent of participants were aware of the implementation of the Cannabis Act. While 78% of physicians were aware of Canadian cannabis consumption driving regulations, only 25% were very comfortable counseling patients regarding safe driving. Forty-six percent of participants felt moderately to very comfortable identifying vulnerable cannabis users. Forty-three percent of participants were moderately to very comfortable identifying counseling patients on recreational cannabis use. Physicians were generally able to identify patient populations who should avoid cannabis and the side effects of cannabis. Physician who had practiced for >10 years were more likely to identify side effects than those with less experience.
Conclusions
Family physicians’ knowledge is inadequate, and they frequently lack confidence to counsel their patients on recreational cannabis use. Most are not aware of assessment tools, which may account for the lack of screening for cannabis use disorder and identification of vulnerable users. There is a need for increased research and targeted medical education regarding recreational cannabis use.
Objectifs
La consommation de cannabis à des fins récréatives a été légalisée au Canada en 2018. Il existe peu de recherches évaluant les capacités des médecins de famille à aborder la consommation de cannabis à des fins récréatives avec les patients. Nous avons cherché à évaluer les connaissances et la pratique des médecins de famille en matière de dépistage et de conseil aux patients sur la consommation légale de cannabis à des fins récréatives.
Méthodes
Les médecins de famille de la Saskatchewan ont été invités à répondre à une enquête transversale, distribuée par la Saskatchewan Medical Association, en janvier-février 2020. L’enquête a saisi les connaissances des médecins de famille sur les pratiques de conseil en matière de cannabis récréatif et les besoins de formation continue.
Résultats
Quatre-vingt-deux questionnaires ont été remplis (taux de réponse de 10%). Quatrevingt-treize pour cent des participants étaient au courant de la mise en oeuvre de la Loi sur le cannabis. Alors que 78% des médecins étaient au courant de la réglementation canadienne sur la consommation de cannabis au volant, seulement 25% étaient très à l’aise de conseiller les patients sur la conduite sécuritaire. Quarante-six pour cent des participants se sentaient de modérément à très à l’aise pour identifier les consommateurs de cannabis vulnérables. Quarantetrois pour cent des participants étaient de modérément à très à l’aise pour conseiller les patients sur la consommation de cannabis à des fins récréatives. Les médecins étaient généralement en mesure d’identifier les populations de patients qui devraient éviter le cannabis et les effets secondaires du cannabis. Les médecins qui avaient pratiqué pendant plus de 10 ans étaient plus susceptibles d’identifier des effets secondaires que ceux qui avaient moins d’expérience.
Conclusions
Les connaissances des médecins de famille sont insuffisantes et ils manquent souvent de confiance pour conseiller leurs patients sur la consommation récréative de cannabis. La plupart ne connaissent pas les outils d’évaluation, ce qui peut expliquer le manque de dépistage des troubles liés à la consommation de cannabis et d’identification des consommateurs vulnérables. Il est nécessaire d’accroître la recherche et l’éducation médicale ciblée concernant la consommation de cannabis à des fins récréatives.
The current review highlights the available research related to cannabis and indicators of physical health in a variety of domains. Various studies have found associations between cannabis use with pulmonary, cardiovascular, gastrointestinal, and endocrine function as well as body mass index and sleep. At this time, more research is needed to understand the influence of cannabis use on physical health, particularly among adolescent samples.
Rationale:
Evidence suggests that the effects of smoking cannabis on lung function are different to tobacco. However, long-term follow-up data are scarce, and mostly based on young adults.
Objective:
To assess the effects of cannabis and tobacco on lung function in mid-adult life.
Methods:
Cannabis and tobacco use were reported at ages 18, 21, 26, 32, 38, and 45 years in a population-based cohort study of 1037 participants. Spirometry, plethysmography, and carbon monoxide transfer factor were measured at age 45. Associations between lung function and cannabis use were adjusted for tobacco use.
Measurements and main results:
Data were available from 881 (88%) of 997 surviving participants. Cumulative cannabis use was associated with lower Forced Expiratory Volume in one second to Forced Vital Capacity ratios, due to a tendency towards higher Forced Vital Capacities. Cannabis use was also associated with higher total lung capacity, functional residual capacity, residual volume, and alveolar volume along with lower mid-expiratory flows, airway conductance, and transfer factor. Quitting regular cannabis use between assessments was not associated with changes in spirometry.
Conclusions:
Cannabis use is associated with higher lung volumes suggesting hyperinflation. There is evidence of increased large-airways resistance and lower mid-expiratory airflow, but impairment of Forced Expiratory Volume in one second to Forced Vital Capacity ratio is due to higher Vital Capacities. This pattern of effects is different to those of tobacco. We provide the first evidence that lifetime cannabis use may be associated with impairment of gas transfer.
Introduction:
Because of widespread use, understanding the pulmonary effects of cannabis use is important but its role independent from tobacco smoking is yet to be elucidated. We used Mendelian randomization (MR) to assess the effect of genetic liability to lifetime cannabis use and cannabis use disorder on pulmonary function and lung cancer.
Methods:
We used four single nucleotide polymorphisms (SNPs) associated with lifetime cannabis use (p value <5x10-8) from a genome-wide association study (GWAS) of 184,765 individuals of European descent from the International Cannabis Consortium, 23andme and UK Biobank as instrumental variables. Seven SNPs (p value <5x10-8) were selected as instruments for cannabis use disorder from a GWAS meta-analysis of 17,068 European ancestry cases and 35,7219 controls of European descent from Psychiatric Genomics Consortium Substance Use Disorders working group, iPSYCH, and deCODE studies. The lung function GWAS included 79,055 study participants of the SpiroMeta Consortium, and a lung cancer GWAS from the International Lung Cancer Consortium (ILCCO) contained 29,266 cases and 56,450 controls.
Results:
MR showed that genetic liability to lifetime cannabis use was associated with increased risk of squamous cell carcinoma (OR = 1.22, 95% CI = 1.07-1.39; p value = 0.003; q value = 0.025). Pleiotropy-robust methods and positive and negative control analyses did not indicate bias in the primary analysis.
Conclusions:
The findings of this MR analysis suggest evidence for a potential causal association between genetic liability for cannabis use and the risk of squamous cell carcinoma. Triangulating MR and observational studies, addressing orthogonal sources of bias, are necessary to confirm this finding.
In the United States, (U.S.), policies regarding the medical and non-medical use of cannabis are changing rapidly. In 2021, a total of 34 U.S. states have legalized cannabis for adult medical use, and 15 of these states have legalized adult non-medical use. These changing policies have raised questions about increasing prevalences of cannabis use, changing perceptions regarding frequent use, and potentially related outcomes such as comorbid psychiatric illness or driving under the influence of cannabis. Research regarding the correlates of any and frequent cannabis use is also developing quickly. This article reviews recent empirical studies concerning (1) adult trends in cannabis use, (2) state cannabis laws and related outcomes, and (3) emerging evidence regarding how the global Coronavirus-19 pandemic may impact cannabis use patterns. We summarize recent findings and conclude with suggestions to address unanticipated effects of rapidly changing cannabis laws and policies.
This study has published https://onlinelibrary.wiley.com/doi/abs/10.1111/add.15381 BACKGROUND AND AIMS: In Great Britain, cannabis and tobacco are commonly used substances, both independently and together. Use of either substance is associated with mental health problems, but prevalence of co-use within these populations is unknown. We aimed to 1) estimate prevalence of cannabis use, frequency of use and routes of administration (ROA) among tobacco smokers and non-smokers and 2) investigate mental health problems amongst non-users, tobacco-only, cannabis-only and co-users of both substances. DESIGN: Cross-sectional national online survey (Action on Smoking and Health) fielded in February–March 2020. SETTING: Great Britain PARTICIPANTS: Adults in Great Britain aged ≥ 18 year (n = 12,809) MEASUREMENTS: Tobacco use status (smoker [daily or non-daily] or non-smoker [never or ex-smoker]), cannabis use frequency (never to daily), detailed ROAs of cannabis, self-reported treatment for mental health disorders (depression, anxiety, and any). Statistically weighted prevalence estimates were computed to ensure representativeness. Correlates were assessed using chi-squared tests and logistic regression. FINDINGS: In Great Britain in 2020, 7.1% of the sample had used cannabis in the past year. Tobacco smokers had greater odds of using cannabis in the past year (21.9%) and using cannabis daily (8.7%) than non-smokers (past-year: 4.7%; aOR=10.07, [95% CI: 8.4 -12.0]; daily: 0.7%; aOR=24.6, [95% CI: 17.96-35.55]). Co-administration with tobacco was common (46.2% of non-smokers, 80.8% of tobacco smokers). Co-users reported the highest prevalence of any treatment for mental health problems (54.2%) in comparison to cannabis-only (45.8%), tobacco-only (33.2%) and non-users (22.7%; all p≤0.05). CONCLUSION: Approximately one in 13 adults in Great Britain reports having used cannabis in the past year, approximately four times as many among cigarette smokers as non-smokers. Co-administration of cannabis and tobacco, via smoking, appears to be common, including among self-identified non-smokers. Mental health problems appear to be particularly common among dual users.
The use of cannabis for medicinal purposes and recreational use across all age groups continues to increase across the United States. Cannabis is reported to be the most commonly used illicit drug in the United States. In recent years, more states have legalized cannabis for both medicinal and recreational use. With the growing public acceptance and prevalence of cannabis use, advanced practice nurses will encounter more patients seeking guidance on the use of cannabis for a variety of conditions. Providers need to be armed with a basic level of knowledge concerning cannabis use, potential side effects, adverse reactions, legal issues, and drug interactions.
Background
Cannabis is the most popular illicit drug among adolescents in developed countries, including Finland. The aim of this study was to estimate 1) how cannabis experimentation among Finnish adolescents changed between 2003 and 2019, and 2) whether the associations between cannabis experiments and factors related to it, especially the use of tobacco and nicotine products, changed during the same time period.
Methods
The analyses are based on the European School Survey Project on Alcohol and Other Drugs data, collected from Finnish adolescents aged 15 to 16 in 2003, 2007, 2011, 2015, and 2019 (N=20,630).
Results
Experimentation with cannabis among Finnish adolescents has increased since the beginning of our follow-up. At the same time, alcohol use and smoking have decreased markedly, and attitudes toward cannabis use have become more relaxed. The association between smoking and cannabis experimentation has become weaker over time. However, the use of tobacco and nicotine products, especially polytobacco, is still a strong risk factor for experimentation with cannabis. The higher the number of tobacco or nicotine products used, the higher the probability for cannabis experimentation.
Conclusions
Experimentation with cannabis has previously been concentrated predominantly on adolescents who smoke, but recently non-smokers are increasingly trying cannabis. It is possible that alternative ways of using cannabis may have increased its use. Despite the strict cannabis policy in Finland, its use has increased, which may be an indication that youth cultures and images of different substances play a significant role in adolescents experimenting with cannabis.
Objectives
Little is known about the prevalence of febrile illness in the Arabian region as clinical, laboratory and immunological profiling remains largely uncharacterised.
Methods
A total of 2018 febrile patients from Jazan, Saudi Arabia, were recruited between 2014 and 2017. Patients were screened for dengue and chikungunya virus, Plasmodium, Brucella, Neisseria meningitidis, group A streptococcus and Leptospira. Clinical history and biochemical parameters from blood tests were collected. Patient sera of selected disease‐confirmed infections were quantified for immune mediators by multiplex microbead‐based immunoassays.
Results
Approximately 20% of febrile patients were tested positive for one of the pathogens, and they presented overlapping clinical and laboratory parameters. Nonetheless, eight disease‐specific immune mediators were identified as potential biomarkers for dengue (MIP‐1α, MCP‐1), malaria (TNF‐α), streptococcal and meningococcal (eotaxin, GRO‐α, RANTES, SDF‐1α and PIGF‐1) infections, with high specificity and sensitivity profiles. Notably, based on the conditional inference model, six of these mediators (MIP‐1α, TNF‐α, GRO‐α, RANTES, SDF‐1α and PIGF‐1) were revealed to be 68.4% accurate in diagnosing different febrile infections, including those of unknown diseases.
Conclusions
This study is the first extensive characterisation of the clinical analysis and immune biomarkers of several clinically important febrile infections in Saudi Arabia. Importantly, an immune signature with robust accuracy, specificity and sensitivity in differentiating several febrile infections was identified, providing useful insights into patient disease management in the Arabian Peninsula.
Background and aims: Cannabis and tobacco use is common in Great Britain. Use of both substances has been associated with mental health problems, but prevalence of their co-use and implications on mental health are unknown. We aimed to 1) estimate prevalence of cannabis use, frequency of use and routes of administration (ROA) among smokers and non-smokers; 2) to investigate mental health problems amongst non-users, tobacco-only, cannabis-only and co-users of both substances. Design: National online survey fielded in February–March 2020. Setting: Great Britain Participants: Adults in Great Britain aged ≥ 18 year (n = 12,809) Measurements: Tobacco use status (smoker [daily or non-daily] or non-smoker [never or ex-smoker]), cannabis use frequency (never to daily), detailed ROAs of cannabis, mental health disorders (depression, anxiety, and any). Weighted prevalence estimates were computed and correlates assessed using chi-squared tests and logistic regression. Findings: In Great Britain in 2020, 7.1% of British adults had used cannabis in the past year. Tobacco smokers has greater odds of using cannabis in the past year (21.9%) and using cannabis daily (8.7%) than non-smokers (past-year: 4.7%; aOR=10.07, [95% CI: 8.4 -12.0]; daily: 0.7%; aOR=24.6, [95% CI: 17.96-35.55]). Co-administration with tobacco was common (46.2% of non-smokers, 80.8% of smokers). Co-users reported the highest prevalence of any mental health problem (54.2%) in comparison to cannabis-only (45.8%), tobacco-only (33.2%) and non-users (22.7%; all p≤0.05). Conclusion: In a representative sample of Great Britain in 2020, tobacco smokers and non-smokers show significant exposure to combusted smoke and tobacco smoke. Self-identified non-smokers who regularly consume combusted cannabis, and smoked cannabis with tobacco warrant further attention. Co-use was associated with greater daily cannabis use, co-administration and mental health problems. Cannabis users should be considered a vulnerable population where rates of tobacco smoking are much higher than in the general population.
Since August 2019, CDC, the Food and Drug Administration (FDA), state and local health departments, and public health and clinical stakeholders have been investigating a nationwide outbreak of e-cigarette, or vaping, product use-associated lung injury (EVALI) (1). This report updates patient demographic characteristics, self-reported substance use, and hospitalization dates for EVALI patients reported to CDC by states, as well as the distribution of emergency department (ED) visits related to e-cigarette, or vaping, products analyzed through the National Syndromic Surveillance Program (NSSP). As of January 14, 2020, a total of 2,668 hospitalized EVALI cases had been reported to CDC. Median patient age was 24 years, and 66% were male. Overall, 82% of EVALI patients reported using any tetrahydrocannabinol (THC)-containing e-cigarette, or vaping, product (including 33% with exclusive THC-containing product use), and 57% of EVALI patients reported using any nicotine-containing product (including 14% with exclusive nicotine-containing product use). Syndromic surveillance indicates that ED visits related to e-cigarette, or vaping, products continue to decline after sharply increasing in August 2019 and peaking in September 2019. Clinicians and public health practitioners should remain vigilant for new EVALI cases. CDC recommends that persons not use THC-containing e-cigarette, or vaping, products, especially those acquired from informal sources such as friends, family members, or from in-person or online dealers. Vitamin E acetate is strongly linked to the EVALI outbreak and should not be added to any e-cigarette, or vaping, products (2). However, evidence is not sufficient to rule out the contribution of other chemicals of concern, including chemicals in either THC- or non-THC-containing products, in some reported EVALI cases.
Importance
Marijuana use is common and growing in the United States amid a trend toward legalization. Exposure to tobacco smoke is a well-described preventable cause of many cancers; the association of marijuana use with the development of cancer is not clear.
Objective
To assess the association of marijuana use with cancer development.
Data Sources
A search of PubMed, Embase, PsycINFO, MEDLINE, and the Cochrane Library was conducted on June 11, 2018, and updated on April 30, 2019. A systematic review and meta-analysis of studies published from January 1, 1973, to April 30, 2019, and references of included studies were performed, with data analyzed from January 2 through October 4, 2019.
Study Selection
English-language studies involving adult marijuana users and reporting cancer development. The search strategy contained the following 2 concepts linked together with the AND operator: marijuana OR marihuana OR tetrahydrocannabinol OR cannabinoid OR cannabis; AND cancer OR malignancy OR carcinoma OR tumor OR neoplasm.
Data Extraction and Synthesis
Two reviewers independently reviewed titles, abstracts, and full-text articles; 3 reviewers independently assessed study characteristics and graded evidence strength by consensus.
Main Outcomes and Measures
Rates of cancer in marijuana users, with ever use defined as at least 1 joint-year exposure (equivalent to 1 joint per day for 1 year), compared with nonusers. Meta-analysis was conducted if there were at least 2 studies of the same design addressing the same cancer without high risk of bias when heterogeneity was low to moderate for the following 4 cancers: lung, head and neck squamous cell carcinoma, oral squamous cell carcinoma, and testicular germ cell tumor (TGCT), with comparisons expressed as odds ratios (ORs) with 95% CIs.
Results
Twenty-five English-language studies (19 case-control, 5 cohort, and 1 cross-sectional) were included; few studies (n = 2) were at low risk of bias. In pooled analysis of case-control studies, ever use of marijuana was not associated with head and neck squamous cell carcinoma or oral cancer. In pooled analysis of 3 case-control studies, more than 10 years of marijuana use (joint-years not reported) was associated with TGCT (OR, 1.36; 95% CI, 1.03-1.81; P = .03; I² = 0%) and nonseminoma TGCT (OR, 1.85; 95% CI, 1.10-3.11; P = .04; I² = 0%). Evaluations of ever use generally found no association with cancers, but exposure levels were low and poorly defined. Findings for lung cancer were mixed, confounded by few marijuana-only smokers, poor exposure assessment, and inadequate adjustment; meta-analysis was not performed for several outcomes.
Conclusions and Relevance
Low-strength evidence suggests that smoking marijuana is associated with developing TGCT; its association with other cancers and the consequences of higher levels of use are unclear. Long-term studies in marijuana-only smokers would improve understanding of marijuana’s association with lung, oral, and other cancers.
Trial Registration
PROSPERO identifier: CRD42018102457
These guidelines incorporate the recent advances in chronic cough pathophysiology, diagnosis and treatment. The concept of cough hypersensitivity has allowed an umbrella term that explains the exquisite sensitivity of patients to external stimuli such a cold air, perfumes, smoke and bleach. Thus adults with chronic cough now have a firm physical explanation for their symptoms based on vagal afferent hypersensitivity. Different treatable traits exist with cough variant asthma/eosinophilic bronchitis responding to anti inflammatory treatment and non acid reflux being treated with promotility agents rather the anti acid drugs. An alternative antitussive strategy is to reduce hypersensitivity by neuromodulation. Low dose morphine is highly effective in a subset of patients with cough resistant to other treatments. Gabapentin and pregabalin are also advocated but in clinical experience they are limited by adverse events. Perhaps the most promising future developments in pharmacotherapy are drugs which tackle neuronal hypersensitivity by blocking excitability of afferent nerves by inhibiting targets such as the ATP receptor (P2X3). Finally cough suppression therapy when performed by competent practitioners can be highly effective. Children are not small adults and a pursuit of an underlying cause for cough is advocated. Thus in toddlers inhalation of a foreign body is common. Persistent bacterial bronchitis is a common and previously unrecognised cause of wet cough in children. Antibiotics, (which, dose, and duration need to be determined) can be curative. Paediatric specific algorithm should be used.
Background:
Lung disease is a common comorbidity in people with HIV/AIDS, independent of smoking status. The effects of marijuana smoking on risk of lung disease in HIV-infected individuals are unclear.
Methods:
In this prospective cohort study, we quantified lung disease risk among men enrolled in the Multicenter AIDS Cohort Study (MACS), a long-term observational cohort of HIV-infected and uninfected men who have sex with men. Eligible participants were aged ≥30 years with self-reported marijuana and tobacco smoking data from biannual study visits between 1996 and 2014. Pulmonary diagnoses were obtained from self-report and medical records. Analyses were performed using Cox models and Generalized Estimating Equations adjusted for tobacco smoking, CD4 T cell count, and other risk factors.
Findings:
1,630 incident pulmonary diagnoses were reported among 1,352 HIV-seropositive and 1,352 HIV-seronegative eligible participants matched for race and baseline age (53,794 total person-visits, median follow-up 10.5 years). 27% of HIV-infected participants reported daily or weekly marijuana smoking for one or more years in follow-up, compared to 18% of uninfected participants (median 4·0 and 4·5 years daily/weekly use, respectively). HIV-infected participants had an increased likelihood of infectious or non-infectious pulmonary diagnoses compared to uninfected participants (33·2% vs. 21·5%, and 20·6% vs. 17·2%, respectively). Among HIV-infected participants, recent marijuana smoking was associated with increased risk of infectious pulmonary diagnoses and chronic bronchitis independent of tobacco smoking and other risk factors for lung disease (hazard ratio [95% confidence interval] 1·43 [1·09-1·86], and 1·54 [1·11-2·13], respectively); these risks were additive in participants smoking both substances. There was no association between marijuana smoking and pulmonary diagnoses in HIV-uninfected participants.
Interpretation:
In this longitudinal study, long-term marijuana smoking was associated with lung disease independent of tobacco smoking and other risk factors in HIV-infected individuals. These findings could be used to reduce modifiable risks of lung disease in high-risk populations.
Background:
The health effects of smoking marijuana are not well-understood.
Purpose:
To examine the association between marijuana use and respiratory symptoms, pulmonary function, and obstructive lung disease among adolescents and adults.
Data sources:
PubMed, Embase, PsycINFO, MEDLINE, and the Cochrane Library from 1 January 1973 to 30 April 2018.
Study selection:
Observational and interventional studies published in English that reported pulmonary outcomes of adolescents and adults who used marijuana.
Data extraction:
Four reviewers independently extracted study characteristics and assessed risk of bias. Three reviewers assessed strength of evidence. Studies of similar design with low or moderate risk of bias and sufficient data were pooled.
Data synthesis:
Twenty-two studies were included. A pooled analysis of 2 prospective studies showed that marijuana use was associated with an increased risk for cough (risk ratio [RR], 2.04 [95% CI, 1.02 to 4.06]) and sputum production (RR, 3.84 [CI, 1.62 to 9.07]). Pooled analysis of cross-sectional studies (1 low and 3 moderate risk of bias) showed that marijuana use was associated with cough (RR, 4.37 [CI, 1.71 to 11.19]), sputum production (RR, 3.40 [CI, 1.99 to 5.79]), wheezing (RR, 2.83 [CI, 1.89 to 4.23]), and dyspnea (RR, 1.56 [CI, 1.33 to 1.83]). Data on pulmonary function and obstructive lung disease were insufficient.
Limitation:
Few studies were at low risk of bias, marijuana exposure was limited in the population studied, cohorts were young overall, assessment of marijuana exposure was not uniform, and study designs varied.
Conclusion:
Low-strength evidence suggests that smoking marijuana is associated with cough, sputum production, and wheezing. Evidence on the association between marijuana use and obstructive lung disease and pulmonary function is insufficient.
Primary funding source:
None. (PROSPERO: CRD42017059224).
As cannabis use increases, physicians need to be familiar with the effects of both cannabis and tobacco on the lungs. However, there have been very few long-term studies of cannabis smoking, mostly due to legality issues and the confounding effects of tobacco. It was previously thought that cannabis and tobacco had similar long-term effects as both cause chronic bronchitis. However, recent large studies have shown that, instead of reducing forced expiratory volume in 1 s and forced vital capacity (FVC), marijuana smoking is associated with increased FVC. The cause of this is unclear, but acute bronchodilator and anti-inflammatory effects of cannabis may be relevant. Bullous lung disease, barotrauma and cannabis smoking have been recognised in case reports and small series. More work is needed to address the effects of cannabis on lung function, imaging and histological changes.
Background:
Cannabis use disorder is the most commonly reported illegal substance use disorder in the general population; although demand for assistance from health services is increasing internationally, only a minority of those with the disorder seek professional assistance. Treatment studies have been published, but pressure to establish public policy requires an updated systematic review of cannabis-specific treatments for adults.
Objectives:
To evaluate the efficacy of psychosocial interventions for cannabis use disorder (compared with inactive control and/or alternative treatment) delivered to adults in an out-patient or community setting.
Search methods:
We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 6), MEDLINE, EMBASE, PsycINFO, the Cumulaive Index to Nursing and Allied Health Literature (CINAHL) and reference lists of articles. Searched literature included all articles published before July 2015.
Selection criteria:
All randomised controlled studies examining a psychosocial intervention for cannabis use disorder (without pharmacological intervention) in comparison with a minimal or inactive treatment control or alternative combinations of psychosocial interventions.
Data collection and analysis:
We used standard methodological procedures as expected by The Cochrane Collaboration.
Main results:
We included 23 randomised controlled trials involving 4045 participants. A total of 15 studies took place in the United States, two in Australia, two in Germany and one each in Switzerland, Canada, Brazil and Ireland. Investigators delivered treatments over approximately seven sessions (range, one to 14) for approximately 12 weeks (range, one to 56).Overall, risk of bias across studies was moderate, that is, no trial was at high risk of selection bias, attrition bias or reporting bias. Further, trials included a large total number of participants, and each trial ensured the fidelity of treatments provided. In contrast, because of the nature of the interventions provided, participant blinding was not possible, and reports of researcher blinding often were unclear or were not provided. Half of the reviewed studies included collateral verification or urinalysis to confirm self report data, leading to concern about performance and detection bias. Finally, concerns of other bias were based on relatively consistent lack of assessment of non-cannabis substance use or use of additional treatments before or during the trial period.A subset of studies provided sufficient detail for comparison of effects of any intervention versus inactive control on primary outcomes of interest at early follow-up (median, four months). Results showed moderate-quality evidence that approximately seven out of 10 intervention participants completed treatment as intended (effect size (ES) 0.71, 95% confidence interval (CI) 0.63 to 0.78, 11 studies, 1424 participants), and that those receiving psychosocial intervention used cannabis on fewer days compared with those given inactive control (mean difference (MD) 5.67, 95% CI 3.08 to 8.26, six studies, 1144 participants). In addition, low-quality evidence revealed that those receiving intervention were more likely to report point-prevalence abstinence (risk ratio (RR) 2.55, 95% CI 1.34 to 4.83, six studies, 1166 participants) and reported fewer symptoms of dependence (standardised mean difference (SMD) 4.15, 95% CI 1.67 to 6.63, four studies, 889 participants) and cannabis-related problems compared with those given inactive control (SMD 3.34, 95% CI 1.26 to 5.42, six studies, 2202 participants). Finally, very low-quality evidence indicated that those receiving intervention reported using fewer joints per day compared with those given inactive control (SMD 3.55, 95% CI 2.51 to 4.59, eight studies, 1600 participants). Notably, subgroup analyses found that interventions of more than four sessions delivered over longer than one month (high intensity) produced consistently improved outcomes (particularly in terms of cannabis use frequency and severity of dependence) in the short term as compared with low-intensity interventions.The most consistent evidence supports the use of cognitive-behavioural therapy (CBT), motivational enhancement therapy (MET) and particularly their combination for assisting with reduction of cannabis use frequency at early follow-up (MET: MD 4.45, 95% CI 1.90 to 7.00, four studies, 612 participants; CBT: MD 10.94, 95% CI 7.44 to 14.44, one study, 134 participants; MET + CBT: MD 7.38, 95% CI 3.18 to 11.57, three studies, 398 participants) and severity of dependence (MET: SMD 4.07, 95% CI 1.97 to 6.17, two studies, 316 participants; MET + CBT: SMD 7.89, 95% CI 0.93 to 14.85, three studies, 573 participants), although no particular intervention was consistently effective at nine-month follow-up or later. In addition, data from five out of six studies supported the utility of adding voucher-based incentives for cannabis-negative urines to enhance treatment effect on cannabis use frequency. A single study found contrasting results throughout a 12-month follow-up period, as post-treatment outcomes related to overall reduction in cannabis use frequency favoured CBT alone without the addition of abstinence-based or treatment adherence-based contingency management. In contrast, evidence of drug counselling, social support, relapse prevention and mindfulness meditation was weak because identified studies were few, information on treatment outcomes insufficient and rates of treatment adherence low. In line with treatments for other substance use, abstinence rates were relatively low overall, with approximately one-quarter of participants abstinent at final follow-up. Finally, three studies found that intervention was comparable with treatment as usual among participants in psychiatric clinics and reported no between-group differences in any of the included outcomes.
Authors' conclusions:
Included studies were heterogeneous in many aspects, and important questions regarding the most effective duration, intensity and type of intervention were raised and partially resolved. Generalisability of findings was unclear, most notably because of the limited number of localities and homogeneous samples of treatment seekers. The rate of abstinence was low and unstable although comparable with treatments for other substance use. Psychosocial intervention was shown, in comparison with minimal treatment controls, to reduce frequency of use and severity of dependence in a fairly durable manner, at least in the short term. Among the included intervention types, an intensive intervention provided over more than four sessions based on the combination of MET and CBT with abstinence-based incentives was most consistently supported for treatment of cannabis use disorder.
Rationale: Given the inconclusive science on the long-term effects of marijuana exposure on lung function, the increasing tetrahydrocannabinol composition of marijuana over time and the increasing legal accessibility of the substance, continued investigation is needed. Objectives: To determine the association between recent and long-term marijuana smoke exposure with spirometric parameters of lung function and symptoms of respiratory health in a large cohort of U.S. adults. Methods: This is a cross-sectional study of U.S. adults who participated in the 2007-2008 and 2009-2010 National Health and Nutrition Examination Survey cycles, using the data from the standardized spirometry and survey questions performed during these years. Measurements and Main Results: In the combined 2007-2010 cohorts, 59.1% had used marijuana at least once in their lifetime and 12.2% had used in the past month. For each additional day of marijuana use in the prior month, there were no associated changes in mean percent predicted FEV1 (0.002% ± 0.04%, P=0.9) but there was an associated increase in mean percent predicted FVC (0.13% ± 0.03%, P<0.01) and decrease in mean FEV1/FVC (-0.1% ± 0.04%, P<0.01). In multivariable regressions, 1-5 and 6-20 joint-years of marijuana use were not associated with an FEV1/FVC < 70% (OR 1.1, 95% confidence interval (CI) 0.7-1.6, P=0.8 and OR 1.2, 95% CI 0.8-1.8, p=0.4, respectively) while > 20 joint-years were associated with a FEV1/FVC <70% (OR 2.1, 95% CI 1.1-3.9, P=0.02). For each additional marijuana joint-year smoked, there was no associated change in mean percent predicted FEV1 (0.02% ± 0.02%, P=1.0), but there was an increase in mean percent predicted FVC (0.07% ± 0.02%, P<0.01) and a decrease in mean FEV1/FVC (-0.03% ± 0.01%, P=0.02). Conclusions: In a large cross-section of U.S. adults, lifetime marijuana use up to 20 joint-years is not associated with adverse changes in spirometric measures of lung health. While > 20 joint-years of marijuana exposure was associated with a two-fold increased odds of a FEV1/FVC < 70%, this was the result of an increase in FVC rather than the disproportional decrease in FEV1 seen with obstructive lung diseases.
The data of a consecutive series of habitual marijuana smokers were retrospectively evaluated and compared with that of non-marijuana smokers to assess differences between the 2 groups.
13 consecutive habitual marijuana smokers were referred for treatment of spontaneous pneumothorax. The demographic, clinical, radiological, and pathological findings of these patients were reviewed and compared with 140 non-marijuana smokers treated for the same pathology at the same time.
Bullae were seen in 8/13 (62%) and 110/140 (78%) of marijuana smokers and non-marijuana smokers, respectively. However, when patients less than 35-years old were considered, the incidence of bulla was higher in marijuana smokers than non-marijuana smokers (7/10 vs. 3/10, p < 0.05). The pathological findings showed a greater presence of inflammatory cells in specimens from marijuana smokers than those of non-marijuana smokers (8/11 vs. 2/42, respectively, p < 0.05). No significant differences in hospital stay and clinical outcome were registered between the 2 groups.
Despite the fact that we were unable to demonstrate that marijuana had a causal role in the development of emphysema, our study showed that marijuana smokers had a higher incidence of inflammatory cells in pathological specimens, which may favor lung injury, thus predisposing to bulla formation.
Forty healthy young subjects, ages 20 to 49 yr, underwent videobronchoscopy, mucosal biopsy, and bronchial lavage to evaluate the airway inflammation produced by habitual smoking of marijuana and/or tobacco. Videotapes were graded in a blinded manner for central airway erythema, edema, and airway secretions using a modified visual bronchitis index. The bronchitis index scores were significantly higher in marijuana smokers (MS), tobacco smokers (TS), and in combined marijuana/tobacco smokers (MTS), than in nonsmokers (NS). As a pathologic correlate, mucosal biopsies were evaluated for the presence of vascular hyperplasia, submucosal edema, inflammatory cell infiltrates, and goblet cell hyperplasia. Biopsies were positive for two of these criteria in 97% of all smokers and for three criteria in 72%. By contrast, none of the biopsies from NS exhibited greater than one positive finding. Finally, as a measure of distal airway inflammation, neutrophil counts and interleukin-8 (IL-8) concentrations were determined in bronchial lavage fluid. The percentage of neutrophils correlated with IL-8 levels and exceeded 20% in 0 of 10 NS, 1 of 9 MS, 2 of 9 TS, and 5 of 10 MTS. We conclude that regular smoking of marijuana by young adults is associated with significant airway inflammation that is similar in frequency, type, and magnitude to that observed in the lungs of tobacco smokers.
'White hat bias' (WHB) (bias leading to distortion of information in the service of what may be perceived to be righteous ends) is documented through quantitative data and anecdotal evidence from the research record regarding the postulated predisposing and protective effects of nutritively sweetened beverages and breastfeeding, respectively, on obesity. Evidence of an apparent WHB is found in a degree sufficient to mislead readers. WHB bias may be conjectured to be fuelled by feelings of righteous zeal, indignation toward certain aspects of industry or other factors. Readers should beware of WHB, and our field should seek methods to minimize it.
Our aim was to determine the combined and independent effects of tobacco and marijuana smoking on respiratory symptoms and chronic obstructive pulmonary disease (COPD) in the general population.
We surveyed a random sample of 878 people aged 40 years or older living in Vancouver, Canada, about their respiratory history and their history of tobacco and marijuana smoking. We performed spirometric testing before and after administration of 200 microg of salbutamol. We examined the association between tobacco and marijuana smoking and COPD.
The prevalence of a history of smoking in this sample was 45.5% (95% confidence interval [CI] 42.2%-48.8%) for marijuana use and 53.1% (95% CI 49.8%-56.4%) for tobacco use. The prevalence of current smoking (in the past 12 months) was 14% for marijuana use and 14% for tobacco use. Compared with nonsmokers, participants who reported smoking only tobacco, but not those who reported smoking only marijuana, experienced more frequent respiratory symptoms (odds ratio [OR] 1.50, 95% CI 1.05-2.14) and were more likely to have COPD (OR 2.74, 95% CI 1.66-4.52). Concurrent use of marijuana and tobacco was associated with increased risk (adjusted for age, asthma and comorbidities) of respiratory symptoms (OR 2.39, 95% CI 1.58-3.62) and COPD (OR 2.90, 95% CI 1.53-5.51) if the lifetime dose of marijuana exceeded 50 marijuana cigarettes. The risks of respiratory symptoms and of COPD were related to a synergistic interaction between marijuana and tobacco.
Smoking both tobacco and marijuana synergistically increased the risk of respiratory symptoms and COPD. Smoking only marijuana was not associated with an increased risk of respiratory symptoms or COPD.
Tobacco smoking has been observed to cause molecular alterations in bronchial epithelium that antedate the development of lung carcinoma. The rising prevalence of marijuana and cocaine use among young adults in the United States prompted us to investigate whether similar molecular and histopathologic alterations occur in habitual smokers of marijuana and/or cocaine who may or may not also smoke tobacco.
Bronchoscopy was performed in 104 healthy volunteer subjects, including 28 nonsmokers and 76 smokers of one or more of the following substances: marijuana, tobacco, and/or cocaine. Bronchial mucosa biopsy specimens and brushings were analyzed for histopathologic changes, for immunohistopathologic expression of intermediate or surrogate end-point markers that are linked to an increased risk of cancer (Ki-67 [a marker of cell proliferation], epidermal growth factor receptor, p53, Her-2/neu [also known as erbB-2 and ERBB2], globular actin, and abnormal DNA ploidy). Reported P values are two-sided.
Smokers of any one substance or of two or more substances exhibited more alterations than nonsmokers in five to nine of the 10 histopathologic parameters investigated (all P < .05), and they exhibited more molecular abnormalities than nonsmokers. Differences between smokers and nonsmokers were statistically significant (all P < or = .01) for Ki-67, epidermal growth factor receptor, globular actin, and DNA ploidy. There was general agreement between the presence of molecular abnormalities and histopathologic alterations; however, when disagreement occurred, the molecular abnormalities (e.g., Ki-67 and epidermal growth factor receptor) were more frequently altered (all P < or = .01).
These findings suggest that smoking marijuana and/or cocaine, like tobacco smoking, exerts field cancerization effects on bronchial epithelium, which may place smokers of these substances at increased risk for the subsequent development of lung cancer.
Background: The past decade has seen unprecedented shifts in the cannabis policy environment, and the public health impacts of these changes will hinge on how they affect patterns of cannabis use and the use and harms associated with other substances.
Objectives: To review existing research on how state cannabis policy impacts substance use, emphasizing studies using methods for causal inference and highlighting gaps in our understanding of policy impacts on evolving cannabis markets.
Methods: Narrative review of quasi-experimental studies for how medical cannabis laws (MCLs) and recreational cannabis laws (RCLs) affect cannabis use and use disorders, as well as the use of or harms from alcohol, opioids, and tobacco.
Results: Research suggests MCLs increase adult but not adolescent cannabis use, and provisions of the laws associated with less regulated supply may increase adult cannabis use disorders. These laws may reduce some opioid-related harms, while their impacts on alcohol and tobacco use remain uncertain. Research on RCLs is just emerging, but findings suggest little impact on the prevalence of adolescent cannabis use, potential increases in college student use, and unknown effects on other substance use.
Conclusions: Research on how MCLs influence cannabis use has advanced our understanding of the importance of heterogeneity in policies, populations, and market dynamics, but studies of how MCLs relate to other substance use often ignore these factors. Understanding effects of cannabis laws requires greater attention to differences in short- versus long-term effects of the laws, nuances of policies and patterns of consumption, and careful consideration of appropriate control groups.
Background
Previous studies have associated marijuana exposure with increased respiratory symptoms and chronic bronchitis among long-term cannabis smokers.The long-term effects of smoked marijuana on lung function remain unclear.
Methods
We determined the association of marijuana smoking with the risk of spirometrically-defined COPD [post-bronchodilator FEV 1 /FVC<0·7] in 5291 population-based individuals and the rate of decline in FEV 1 in a subset of 1285 men and women, aged 40 years and older, who self-reported use (or nonuse) of marijuana and tobacco cigarettes and performed spirometry before and after inhaled bronchodilator on multiple occasions. Analysis for the decline in FEV 1 was performed using random mixed effects regression models adjusted for age, gender, and body mass index. Heavy tobacco smoking and marijunana smoking was defined as >20 pack-years and >20 joint-years, respectively.
Results
Approximately 20% of participants had been or were current marijuana smokers with most also having smoked tobacco cigarettes (83%). Among heavy marijuana users, the risk of COPD was significantly increased (adjusted odds ratio, aOR, 2.45; 95% CI, 1.55–3.88). Compared to never-smokers of marijuana and tobacco, heavy marijuana smokers and heavy tobacco smokers experienced a faster decline in FEV 1 by 29·5 mL·year ⁻¹ (p=0·0007) and 21·1 mL·year ⁻¹ (p<0.0001), respectively.Those who smoked both experienced a decline of 32.31 mL·year ⁻¹ (p<.0001).
Interpretation
Heavry marijuana smoking increases the risk of COPD and accelerates FEV 1 decline in concomitant tobacco smokers beyond that observed with tobacco alone.
Background:
Cannabis use is a potential risk factor for respiratory disease but its role apart from tobacco use is unclear. We evaluated the association between regular cannabis use, with and without tobacco co-use, and onset of asthma, chronic obstructive pulmonary disease (COPD), and pneumonia.
Methods:
Analysis of a limited data set obtained through IBM Watson Health Explorys, an electronic-health-record-integration platform. Matched controls using Mahalanobis distance within propensity score calipers were defined for: 1) cannabis-using patients (n = 8932); and subgroups of cannabis-using patients: 2) with an encounter diagnosis for tobacco use disorder (TUD; n = 4678); and 3) without a TUD diagnosis (non-TUD; n = 4254). Patients had at least: one recorded blood pressure measurement and one blood chemistry lab result in the MetroHealth System (Cleveland, Ohio). Cannabis-using patients had an encounter diagnosis of cannabis abuse/dependence and/or ≥2 cannabis-positive urine drug screens (UDSs). Control patients, not having cannabis-related diagnoses or cannabis-positive UDSs, were matched to the cannabis-using patients on demographics, residential zip code median income, body mass index, and, for the total sample, TUD-status.
Results:
Regular cannabis use was significantly associated with greater risk for asthma (odds ratio (OR) = 1.44; adjusted odds ratio (aOR) = 1.50; OR = 1.32), COPD (OR = 1.56; aOR = 1.44; OR = 2.17), and pneumonia (OR = 1.80; OR = 1.84; OR = 2.13) in the total sample and TUD and non-TUD subgroups, respectively. TUD-patients had the greatest prevalence of respiratory disease, regardless of cannabis-use indication.
Conclusions:
Regular cannabis use is associated with significantly greater risk of respiratory disease regardless of TUD status. Future research to understand the impact of cannabis use on respiratory health is warranted.
Background: The smoke generated from cannabis delivers biologically active cannabinoids and a number of combustion-derived toxins, both of which raise questions regarding the impact of cannabis smoking on lung function, airway inflammation and smoking-related lung disease.
Objectives: Review the potential effects of cannabis smoking on respiratory symptoms, lung function, histologic/molecular alterations in the bronchial mucosa, smoking-related changes in alveolar macrophage function and the potential clinical impact of cannabis smoking on chronic obstructive pulmonary disease, lung cancer and pulmonary infections.
Methods: Focused literature review.
Results: The carcinogens and respiratory toxins in cannabis and tobacco smoke are similar but the smoking topography for cannabis results in higher per-puff exposures to inhaled tar and gases. The frequency of chronic cough, sputum and wheeze and the presence of airway mucosal inflammation, goblet cell and vascular hyperplasia, metaplasia and cellular disorganization are similar between cannabis smokers and tobacco smokers. Cannabis smoke has modest airway bronchodilator properties but of unclear clinical significance. While clear evidence exists for progression to obstructive lung disease and emphysema in chronic tobacco smokers, the effects from habitual cannabis use are less clear. Evidence suggests that alveolar macrophages from cannabis smokers have deficits in cytokine production and antimicrobial activity not present in cells from tobacco smokers.
Conclusions: Solid conclusions regarding the respiratory consequences of regular cannabis smoking are difficult to make due to a relative paucity of literature, confounding by concurrent tobacco smoking and reports of conflicting outcomes. Additional well-controlled clinical studies on the pulmonary consequences of habitual cannabis use are needed.
Background:
Globally, cannabis use is prevalent and widespread. There are currently no pharmacotherapies approved for treatment of cannabis use disorders.This is an update of a Cochrane Review first published in the Cochrane Library in Issue 12, 2014.
Objectives:
To assess the effectiveness and safety of pharmacotherapies as compared with each other, placebo or no pharmacotherapy (supportive care) for reducing symptoms of cannabis withdrawal and promoting cessation or reduction of cannabis use.
Search methods:
We updated our searches of the following databases to March 2018: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, PsycINFO and Web of Science.
Selection criteria:
Randomised controlled trials (RCTs) and quasi-RCTs involving the use of medications to treat cannabis withdrawal or to promote cessation or reduction of cannabis use, or both, in comparison with other medications, placebo or no medication (supportive care) in people diagnosed as cannabis dependent or who were likely to be dependent.
Data collection and analysis:
We used standard methodological procedures expected by Cochrane.
Main results:
We included 21 RCTs involving 1755 participants: 18 studies recruited adults (mean age 22 to 41 years); three studies targeted young people (mean age 20 years). Most (75%) participants were male. The studies were at low risk of performance, detection and selective outcome reporting bias. One study was at risk of selection bias, and three studies were at risk of attrition bias.All studies involved comparison of active medication and placebo. The medications were diverse, as were the outcomes reported, which limited the extent of analysis.Abstinence at end of treatment was no more likely with Δ9-tetrahydrocannabinol (THC) preparations than with placebo (risk ratio (RR) 0.98, 95% confidence interval (CI) 0.64 to 1.52; 305 participants; 3 studies; moderate-quality evidence). For selective serotonin reuptake inhibitor (SSRI) antidepressants, mixed action antidepressants, anticonvulsants and mood stabilisers, buspirone and N-acetylcysteine, there was no difference in the likelihood of abstinence at end of treatment compared to placebo (low- to very low-quality evidence).There was qualitative evidence of reduced intensity of withdrawal symptoms with THC preparations compared to placebo. For other pharmacotherapies, this outcome was either not examined, or no significant differences was reported.Adverse effects were no more likely with THC preparations (RR 1.02, 95% CI 0.89 to 1.17; 318 participants; 3 studies) or N-acetylcysteine (RR 0.94, 95% CI 0.71 to 1.23; 418 participants; 2 studies) compared to placebo (moderate-quality evidence). For SSRI antidepressants, mixed action antidepressants, buspirone and N-acetylcysteine, there was no difference in adverse effects compared to placebo (low- to very low-quality evidence).There was no difference in the likelihood of withdrawal from treatment due to adverse effects with THC preparations, SSRIs antidepressants, mixed action antidepressants, anticonvulsants and mood stabilisers, buspirone and N-acetylcysteine compared to placebo (low- to very low-quality evidence).There was no difference in the likelihood of treatment completion with THC preparations, SSRI antidepressants, mixed action antidepressants and buspirone compared to placebo (low- to very low-quality evidence) or with N-acetylcysteine compared to placebo (RR 1.06, 95% CI 0.93 to 1.21; 418 participants; 2 studies; moderate-quality evidence). Anticonvulsants and mood stabilisers appeared to reduce the likelihood of treatment completion (RR 0.66, 95% CI 0.47 to 0.92; 141 participants; 3 studies; low-quality evidence).Available evidence on gabapentin (anticonvulsant), oxytocin (neuropeptide) and atomoxetine was insufficient for estimates of effectiveness.
Authors' conclusions:
There is incomplete evidence for all of the pharmacotherapies investigated, and for many outcomes the quality of the evidence was low or very low. Findings indicate that SSRI antidepressants, mixed action antidepressants, bupropion, buspirone and atomoxetine are probably of little value in the treatment of cannabis dependence. Given the limited evidence of efficacy, THC preparations should be considered still experimental, with some positive effects on withdrawal symptoms and craving. The evidence base for the anticonvulsant gabapentin, oxytocin, and N-acetylcysteine is weak, but these medications are also worth further investigation.
http://deepblue.lib.umich.edu/bitstream/null/1/2019-20 VOL II FINAL 3.pdf
As marijuana smoking prevalence increases in the U.S. concern regarding its potential risks to lung health has also risen, given the general similarity in the smoke contents between marijuana and tobacco. Most studies have found a significant association between marijuana smoking and chronic bronchitis symptoms after adjustment for tobacco. While reports are mixed regarding associations between marijuana smoking and lung function, none has shown a relationship to decrements in forced expired volume in 1 sec (FEV1) and few have found a relationship to a decreased ratio of FEV1 to forced vital capacity (FVC), possibly related to an association between marijuana and an increased FVC. A few studies have found a modest reduction in specific airway conductance in relation to marijuana, probably reflecting endoscopic evidence of bronchial mucosal edema among habitual marijuana smokers. Diffusing capacity in marijuana smokers has been normal and two studies of thoracic high-resolution computed tomography (HRCT) have not shown any association of marijuana smoking with emphysema. Although bronchial biopsies from habitual marijuana smokers have shown precancerous histopathological changes, a large cohort study and a pooled analysis of six well-designed case-control studies have not found evidence of a link between marijuana smoking and lung cancer. The immunosuppressive effects of delta-9 tetrahydrocannabinol raise the possibility of an increased risk of pneumonia, but further studies are needed to evaluate this potential risk. Several cases series have demonstrated pneumothoraces/pneumomediastinum, as well as bullous lung disease, in marijuana smokers, but these associations require epidemiologic studies for firmer evidence of possible causality.
Background:
Marijuana is often smoked via a filterless cigarette and contains similar chemical makeup as smoked tobacco. There are few publications describing usage patterns and respiratory risks in older adults or in those with chronic obstructive pulmonary disease (COPD).Methods:A cross-sectional analysis of current and former tobacco smokers from the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS) study assessed associations between marijuana use and pulmonary outcomes. Marijuana use was defined as never, former (use over 30 days ago), or current (use within 30 days). Respiratory health was assessed using quantitative high-resolution computed tomography (HRCT) scans, pulmonary function tests and questionnaire responses about respiratory symptoms.Results:Of the total 2304 participants, 1130 (49%) never, 982 (43%) former, and 192 (8%) current marijuana users were included. Neither current nor former marijuana use was associated with increased odds of wheeze (odds ratio [OR] 0.87, OR 0.97), cough (OR 1.22; OR 0.93) or chronic bronchitis (OR 0.87; OR 1.00) when compared to never users. Current and former marijuana users had lower quantitative emphysema (P=0.004,P=0.03), higher percent predicted forced expiratory volume in 1 second (FEV1%) (P<0.001,P<0.001), and percent predicted forced vital capacity (FVC%) (p<0.001,P<0.001). Current marijuana users exhibited higher total tissue volume (P=0.003) while former users had higher air trapping (P<0.001) when compared to never marijuana users.Conclusions:Marijuana use was found to have little to no association with poor pulmonary health in older current and former tobacco smokers after adjusting for covariates. Higher forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) was observed among current marijuana users. However, higher joint years was associated with more chronic bronchitis symptoms (e.g., wheeze), and this study cannot determine if long-term heavy marijuana smoking in the absence of tobacco smoking is associated with lung symptoms, airflow obstruction, or emphysema, particularly in those who have never smoked tobacco cigarettes.
Background:
Cannabis use is common, and associated with adverse health outcomes. 'Routes of administration' (ROAs) for cannabis use have increasingly diversified, in part influenced by developments towards legalization. This paper sought to review data on prevalence and health outcomes associated with different ROAs.
Methods:
This scoping review followed a structured approach. Electronic searches for English-language peer-reviewed publications were conducted in primary databases (i.e., MEDLINE, EMBASE, PsycINFO, Google Scholar) based on pertinent keywords. Studies were included if they contained information on prevalence and/or health outcomes related to cannabis use ROAs. Relevant data were screened, extracted and narratively summarized under distinct ROA categories.
Results:
Overall, there is a paucity of rigorous and high-quality data on health outcomes from cannabis ROAs, especially in direct and quantifiable comparison. Most data exist on smoking combusted cannabis, which is associated with various adverse respiratory system outcomes (e.g., bronchitis, lung function). Vaporizing natural cannabis and ingesting edibles appear to reduce respiratory system problems, but may come with other risks (e.g., delayed impairment, use 'normalization'). Vaporizing cannabis concentrates can result in distinct acute risks (e.g., excessive impairment, injuries). Other ROAs are uncommon and under-researched.
Conclusions:
ROAs appear to distinctly influence health outcomes from cannabis use, yet systematic data for comparative assessments are largely lacking; these evidence gaps require filling. Especially in emerging legalization regimes, ROAs should be subject to evidence-based regulation towards improved public health outcomes. Concretely, vaporizers and edibles may offer potential for reduced health risks, especially concerning respiratory problems. Adequate cannabis product regulation (e.g., purity, labeling, THC-restrictions) is required to complement ROA-based effects.
Background:
We performed systematic reviews using the PICO format to answer the following key clinical question: Are the CHEST 2006 classifications of acute, subacute and chronic cough and associated management algorithms in adults that were based upon durations of cough useful?
Methods:
We used the CHEST expert cough panel's protocol for the systematic reviews and the American College of Chest Physicians (CHEST) methodological guidelines and GRADE framework. Data from the systematic reviews in conjunction with patients' values and preferences and the clinical context were used to form recommendations or suggestions. Delphi methodology was used to obtain the final grading.
Results:
With respect to acute cough (< 3 weeks), only 3 studies met our criteria for quality assessment and all had a high risk of bias. As predicted by the 2006 CHEST Cough Guidelines, the most common causes were respiratory infections, most likely viral in etiology, followed by exacerbations of underlying diseases such as asthma and COPD, and pneumonia. The subjects resided on 3 continents, North America, Europe, and Asia. With respect to subacute cough (3-8 weeks), only 2 studies met our criteria for quality assessment and all had a high risk of bias. As predicted by the 2006 Guidelines, the most common causes were postinfectious cough and exacerbation of underlying diseases such as asthma, COPD, and upper airway cough syndrome. The subjects resided in countries in Asia. With respect to chronic cough (> 8 weeks), 11 studies met our criteria for quality assessment and all had a high risk of bias. As predicted by the 2006 Guidelins, the most common causes were upper airway cough syndrome from rhinosinus conditions, asthma, gastroesophageal reflux disease, non-asthmatic eosinophilic bronchitis, combinations of these 4, and, less commonly, a variety of miscellaneous conditions and atopic cough in Asian countries. The subjects resided on 4 continents, North America, South America, Europe, and Asia.
Conclusion:
While the quality of evidence was low, the published literature since 2006 suggests that the CHEST Organization's 2006 Cough Guidelines and management algorithms for acute, subacute, and chronic cough in adults appeared useful in diagnosing and treating patients with cough around the globe. These same algorithms have been updated to reflect the advances in cough management as of 2017.
Marijuana (Cannabis sativa I.) has become the second most widely used smoke product in the Western World1-2-3-4. Marijuana smoke, however, is inhaled in significantly lower doses than tobacco smoke and its effect is predominantly psychotomimetic with some acute toxic side effects. Nevertheless, information as to the carcinogenicity of this inhalant is needed. Since most marijuana smokers are also cigarette smokers, it needs furthermore to be determined whether marijuana smoke can potentiate the carcinogenic effect of tobacco smoke.
Previous studies of the long-term effects of habitual marijuana smoking on respiratory status and lung function have yielded conflicting results. In the present study, lung function tests obtained in 74 regular marijuana smokers (duration of smoking > two-five years; frequency of smoking three days/week to several times/day) who denied intravenous narcotic drug abuse were compared with similar tests performed in two groups of control subjects. One group consisted of individuals tested in a mobile laboratory who were computer-matched to the marijuana smokers for anthropometric characteristics and quantity and duration of tobacco smoking; the other group was comprised of 41 nonsmokers of marijuana who were tested in the same laboratory as the marijuana smokers. Paired and unpaired t analyses revealed lower values for specific airway conductance (-0.07 to -0.08 +/- 0.02; P < 0.001) in the marijuana smokers compared with either group of control subjects, but no differences in spirometric indices, closing volume or delta N2 750-1250. When non-tobacco smoking marijuana users (n = 50) were matched with either non-tobacco smoking or tobacco smoking control subjects, significant differences were again noted in specific airway conductance (P < 0.001) but not in spirometric tests, closing volume or delta N2 750-1250. These results suggest that habitual smoking of marijuana may cause mild, but significant, functional impairment predominantly involving large airways which is not detectable in individuals of the same age who regularly smoke tobacco. The clinical implications of these findings await further study.
Smoking cannabis is associated with symptoms of bronchitis. Little is known about the persistence of symptoms after stopping cannabis use. We assessed associations between changes in cannabis use and respiratory symptoms in a population-based cohort of 1037 young adults. Participants were asked about cannabis and tobacco use at ages 18, 21, 26, 32 and 38 years. Symptoms of morning cough, sputum production, wheeze, dyspnoea on exertion and asthma diagnoses were ascertained at the same ages. Frequent cannabis use was defined as ⩾52 occasions over the previous year. Associations between frequent cannabis use and respiratory symptoms were analysed using generalised estimating equations with adjustments for tobacco smoking, asthma, sex and age. Frequent cannabis use was associated with morning cough (OR 1.97, p<0.001), sputum production (OR 2.31, p<0.001) and wheeze (OR 1.55, p<0.001). Reducing or quitting cannabis use was associated with reductions in the prevalence of cough, sputum and wheeze to levels similar to nonusers. Frequent cannabis use is associated with symptoms of bronchitis in young adults. Reducing cannabis use often leads to a resolution of these symptoms.
Copyright ©ERS 2015.
Health concerns around cannabis use have focused on the potential relationship with psychosis but the effect of cannabis smoking on respiratory health has received less attention.
To investigate the association between tobacco-only smoking compared with tobacco plus cannabis smoking and adverse outcomes in respiratory health and lung function.
The design was cross-sectional with two groups recruited: cigarette smokers with tobacco pack-years; cannabis smokers with cannabis joint-years. Recruitment occurred in a general practice in Scotland with 12 500 patients.
Exposures measured were tobacco smoking (pack-years) and cannabis smoking (joint-years). Cannabis type (resin, herbal, or both) was recorded by self-report. Respiratory symptoms were recorded using NHANES and MRC questionnaires. Lung function was measured by spirometry (FEV1/FVC ratio).
Participants consisted of 500 individuals (242 males). Mean age of tobacco-only smokers was 45 years; median tobacco exposure was 25 pack-years. Mean age of cannabis and tobacco smokers was 37 years; median tobacco exposure was 19 pack-years, rising to 22.5 when tobacco smoked with cannabis. Although tobacco and cannabis use were associated with increased reporting of respiratory symptoms, this was higher among those who also smoked cannabis. Both tobacco and cannabis users had evidence of impaired lung function but, in fully adjusted analyses, each additional joint-year of cannabis use was associated with a 0.3% (95% confidence interval = 0.0 to 0.5) increase in prevalence of chronic obstructive pulmonary disease.
In adults who predominantly smoked resin cannabis mixed with tobacco, additional adverse effects were observed on respiratory health relating to cannabis use.
© British Journal of General Practice 2015.
Background
Lung cancer remains the leading cause of cancer death worldwide, with tobacco smoking established as the main risk factor. Cannabis smoke contains similar carcinogens as tobacco smoke including the polycyclic aromatic hydrocarbons; animal studies and human case series and histopathologic studies have suggested its potential carcinogenic effect in lungs. However, epidemiologic evidence is limited and conflicting. The present study aimed to examine the role of cannabis smoking in lung cancer risk using a pooled analysis in the International Lung Cancer Consortium (ILCCO).
Methods
Cannabis smoking and putative lung cancer risk factor data on 2131 lung cancer cases and 3075 controls were harmonized and pooled from six case-control studies in US, Canada, UK and New Zealand within the ILCCO. To standardize the definition and to distinguish occasional/non-users from habitual users, cumulative consumption of 1 joint-year (1 joint-equivalent per day for 1 year) or more was used to define habitual vs. non-users. The association between cannabis smoking (habitual vs. non-users, joint-equivalent per day, duration, and total joint-years) and the risk of lung cancer was assessed by odds ratios (OR) and 95% confidence intervals (CI) obtained from unconditional logistic regression in each study, while adjusting for age, sex, sociodemographic factors and tobacco packyears. Pooled risk estimates were calculated using random effect models. To minimize confounding by tobacco smoking, we also conducted analyses restricted to 367 case and 1400 control never tobacco smokers.
Results
The summary OR from the six studies for habitual vs. non-users was 1.15 (95% CI: 0.73-1.82, p for heterogeneity: 0.05). Compared to non-users, the summary OR was 1.28 (95%CI: 0.62-2.63) for individuals who smoked cannabis for 20 years or more and 1.53 (95%CI: 0.57-4.09) for those with 10 joint-years or more cumulative consumption. A lack of significant association between cannabis smoking and lung cancer was also observed in the never tobacco smokers: compared to non-users, the OR was 0.99 (95% CI: 0.49-2.00) for habitual users and 2.13 (95%CI: 0.67-6.78) for those who used 20 years or more.
Conclusion
Our pooled results showed no significant association between the intensity, duration, or cumulative consumption of cannabis smoke and the risk of lung cancer overall or in never smokers. Cannabis use is under international control and its legal status varies, so reporting bias is of concern. However, since the reported prevalence in our data is comparable to nation-specific survey results and not differential between cases and controls, it is unlikely to fully explain the lack of significant association. Our results cannot preclude the possibility that cannabis may exhibit an association with lung cancer risk at extremely high dosage. We will also present data after applying restricted cubic splines to explore non-linear relationships.
Citation Format: Li Rita Zhang, Zuo-Feng Zhang, Hal Morgenstern, Shen-Chih Chang, Philip Lazarus, M. Dawn Teare, Penella J. Woll, Irene Orlow, Brian Cox, Geoffrey Liu, Rayjean J. Hung. Cannabis smoking and lung cancer risk: pooled analysis in the International Lung Cancer Consortium. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3633. doi:10.1158/1538-7445.AM2013-3633
Marijuana smoking is widespread in many countries and the use of smoked synthetic cannabinoids is increasing. Smoking a marijuana joint leads to bronchodilation in both healthy subjects and asthmatics. The effects of delta-9-tetrahydrocannabinol and synthetic cannabinoids on human bronchus reactivity have not previously been investigated. Here, we sought to assess the effects of natural and synthetic cannabinoids on cholinergic bronchial contraction.
Human bronchi isolated from 88 patients were suspended in an organ bath and subjected to electrical field stimulation in the presence of the phytocannabinoid delta-9-tetrahydrocannabinol, the endogenous 2-arachidonoylglycerol, the synthetic dual CB1 and CB2 receptor agonists WIN55,212-2 and CP55,940, the synthetic, CB2-receptor-selective agonist JWH-133 or the selective GPR55 agonist O-1602. The receptors involved in the response were characterised by using selective CB1 and CB2 receptor antagonists (SR141716 and SR144528, respectively).
Delta-9-tetrahydrocannabinol, WIN55,212-2 and CP55,940 induced concentration-dependent inhibition of cholinergic contraction, with maximum inhibitions of 39%, 76% and 77%, respectively. JWH-133 only had an effect at high concentrations. 2-arachidonoylglycerol and O-1602 were devoid of any effect. Only CB1 receptors were involved in the response, since the effects of cannabinoids were antagonised by SR141716 but not by SR144528. The cannabinoids did not alter basal tone or exogenous, acetylcholine-induced contraction.
Activation of prejunctional CB1-receptors appears to mediate the inhibition of electrical field stimulation-evoked cholinergic contraction in human bronchus. This feature may explain the acute bronchodilation produced by marijuana smoking.
Cannabis (marijuana) smoke and tobacco smoke contain many of the same potent carcinogens, but a critical-yet unresolved-medical and public-health issue is whether cannabis smoking might facilitate the development of lung cancer. The current study aimed to assess the risk of lung cancer among young marijuana users.
A population-based cohort study examined men (n = 49,321) aged 18-20 years old assessed for cannabis use and other relevant variables during military conscription in Sweden in 1969-1970. Participants were tracked until 2009 for incident lung cancer outcomes in nationwide linked medical registries. Cox regression modeling assessed relationships between cannabis smoking, measured at conscription, and the hazard of subsequently receiving a lung cancer diagnosis.
At the baseline conscription assessment, 10.5 % (n = 5,156) reported lifetime use of marijuana and 1.7 % (n = 831) indicated lifetime use of more than 50 times, designated as "heavy" use. Cox regression analyses (n = 44,284) found that such "heavy" cannabis smoking was significantly associated with more than a twofold risk (hazard ratio 2.12, 95 % CI 1.08-4.14) of developing lung cancer over the 40-year follow-up period, even after statistical adjustment for baseline tobacco use, alcohol use, respiratory conditions, and socioeconomic status.
Our primary finding provides initial longitudinal evidence that cannabis use might elevate the risk of lung cancer. In light of the widespread use of marijuana, especially among adolescents and young adults, our study provides important data for informing the risk-benefit calculus of marijuana smoking in medical, public-health, and drug-policy settings.