Conference Paper

Racial Difference in the Long-Term Effects of Marijuana Use on Physical Health Outcomes

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Abstract

Introduction:Health benefits of marijuana use have been identified for several diseases such as glaucoma, cancer, HIV-AIDS, multiple sclerosis, and Crohn’s disease. In fact, more than 100 conditions qualify for medical marijuana in California. Conversely, only a few definitive negative health effects of marijuana have been found, including respiratory problems, cardiovascular risks, and cognitive impairments. Nevertheless, few studies have prospectively examined the long-term effects of marijuana use on physical health. Even rarer are studies examining race differences in these effects, which is critical given health disparities generally favoring Whites and generally higher rates of marijuana use among Black than White adults. The purpose of this study was to examine racial differences in the effects of chronic and intensive marijuana use during adolescence and/or emerging adulthood (ages 18-25) on physical health symptoms in young adulthood (age 35). Methods: We used data from 487 young men who were interviewed annually from the 7thgrade until age 25 and then again at age 35. Four trajectory groups of regular (approximately monthly) marijuana use between ages 12 and 25 were identified: nonusers/nonregular users, adolescence-limited, late-onset, and chronic regular marijuana users. Results: ANCOVAs (covarying race) and Chi-square tests indicated no trajectory group differences in the number of current health problems, number of medications currently taken for physical illnesses, number of physical injuries, ever being shot by age 35, and being hospitalized in the past year. We also used regression analyses to examine the effects of marijuana use at age 25 and at age 35, race, and their interactions on these same outcomes at age 35. There were no significant effects of quantity or frequency of use in the total sample or among users only on any of the health outcomes. There were also no health differences between Blacks and Whites except that Blacks were more likely to have been shot by age 35. Conclusions: It appears that continuous monthly marijuana use from adolescence through emerging adulthood is not a high enough threshold to lead to negative health outcomes at least by young adulthood and that frequent use in emerging or young adulthood is also not related to health outcomes. Given that there were relatively few serious illnesses in this sample by young adulthood, it is possible that negative consequences of marijuana use will become evident at later ages. Prevention programs should highlight psychosocial rather than physical health consequences.

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... As marijuana use is associated with both positive and negative health outcomes, there is a continuing need to investigate the good and the bad of marijuana use (Hasin, 2018). Of note, consistent monthly marijuana use from adolescence to young adulthood is not a sufficient threshold to associate with negative health outcomes (White, Simpson, Pardini, & Finlay, 2013). In other words, monthly marijuana use among boys does not make a significant difference to 35-year-old men's health issues in general including medications, injuries, or hospitalizations, compared with those who did not consume marijuana (White et al., 2013). ...
... Of note, consistent monthly marijuana use from adolescence to young adulthood is not a sufficient threshold to associate with negative health outcomes (White, Simpson, Pardini, & Finlay, 2013). In other words, monthly marijuana use among boys does not make a significant difference to 35-year-old men's health issues in general including medications, injuries, or hospitalizations, compared with those who did not consume marijuana (White et al., 2013). However, weekly use is a key to human health. ...
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This investigation studied the association between developmental trajectories of marijuana use extending from adolescence to age 32 and later antisocial behavior at age 37. Semi-parametric group-based modeling and logistic regression analyses were used to analyze the data. Five distinct trajectories of marijuana use were identified: never-users, quitters/decreasers, occasional users, chronic users, and increasing users. Being either a chronic user or an increasing marijuana user was associated with an increase in the risk of exhibiting antisocial behavior in adulthood. Both chronic and increasing use of marijuana may serve as predictors of adult antisocial behavior. Treatment programs to prevent antisocial behavior across the life course should include a component to address earlier and concurrent marijuana use.
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Cannabis use is one of the environmental factors with more solid evidence contributing to schizophrenia risk, especially in genetically susceptible individuals. One of the genes that may interact with cannabis is COMT, although available data are scarce. Here, we present a case-only study of the putative COMT-cannabis interaction in schizophrenia. Two Spanish samples from Santiago de Compostela and Valencia were screened for cannabis use. One hundred and fifty five individuals from a total of 748 patients were identified as cannabis users. Five SNPs in COMT, defining three common functional haplotypes with different enzymatic activities, were genotyped and analyzed for association at the SNP, haplotype and genotype levels. An association was detected between cannabis use and low activity variants (P<0.01) in the joint analysis and results were consistent between the two samples. Schizophrenic subjects homozygous for the Met allele at rs4680 doubled the probability of lifetime prevalence of cannabis use in comparison to Val homozygous (Mantel-Haenszel OR=2.07, 95% CI: 1.27-3.26, P=0.0031, in the combined sample). These data are in contrast to those from Caspi et al. (Biol. Psychiatry 57 (2005)1117-1127) who found association between schizophrenia/schizophreniform disorder and homozygosity at the high activity Val variant of rs4680. The results of our study are discussed in the context of previous findings, suggesting the involvement of COMT polymorphisms in the association between cannabis use and schizophrenia as well as the existence of additional factors mediating this association. However, further research is needed to confirm the COMT-cannabis interaction.
Article
Scientific findings show that substance abuse in women yields a higher risk of a variety of health problems than substance abuse in men. Research suggests that women experience addiction telescoping when they abuse alcohol, tobacco, specific stimulants, and possibly opioids. Medical side effects also develop more rapidly in women than men when they abuse many substances. Cancer and cardiac complications, specifically, pose a significant threat for women who abuse almost all types of substances. However, the physical consequences are not the only ones women suffer when they engage in substance abuse. Research on substance abuse in women ties opioids to mood and anxiety disorders, heroin to neurological deficiencies, cocaine to immune system suppression, and alcohol to intimate partner abuse. Additionally, female substance abusers, on average, have a lower level of education and lower rates of employment. In light of these gender-specific concerns, physicians should give particular consideration to detecting substance abuse in women.
Article
Cannabis is the most widely consumed illicit drug worldwide and the relation between cannabis smoking and lung cancer is suggestive, albeit inconclusive. We conducted three hospital based case-control studies in Tunisia, Morocco, and Algeria, three areas of high prevalence of cannabis consumption as well as production. This paper presents the pooled analysis of these three studies restricted to men with a total of 430 cases and 778 controls. Ninety-six percent of the cases and 67.8% of the controls were tobacco smokers and 15.3% of the cases and 5% of the controls were ever cannabis smokers. All cannabis smokers were tobacco users. Adjusting for country, age, tobacco smoking, and occupational exposure, the odds ratio (OR) for lung cancer was 2.4 (95% confidence interval [CI]: 1.6-3.8) for ever cannabis smoking. This association remained after adjustment for lifetime tobacco packyears as continuous variable, OR = 2.3 (95% CI: 1.5-3.6). The OR adjusted for intensity of tobacco smoking (cigarette/d) among current tobacco smokers and never cannabis smokers was 10.9 (95% CI: 6.0-19.7) and the OR among current tobacco users and ever cannabis smokers was 18.2 (95% CI: 8.0-41.0). The risk of lung cancer increased with increasing joint-years, but not with increasing dose or duration of cannabis smoking. Our results suggest that cannabis smoking may be a risk factor for lung cancer. However, residual confounding by tobacco smoking or other potential confounders may explain part of the increased risk.
Article
The purpose of this retrospective cohort study was to examine the relationship of marijuana use to cancer incidence. The study population consisted of 64,855 examinees in the Kaiser Permanente multiphasic health checkup in San Francisco and Oakland (California, United States), between 1979-85, aged 15 to 49 years, who completed self-administered questionnaires about smoking habits, including marijuana use. Follow-up for cancer incidence was conducted through 1993 (mean length 8.6 years). Compared with nonusers/experimenters (lifetime use of less than seven times), ever- and current use of marijuana were not associated with increased risk of cancer of all sites (relative risk [RR] = 0.9, 95 percent confidence interval [CI] = 0.7-12 for ever-use in men; RR = 1.0, CI = 0.8-1.1 in women) in analyses adjusted for sociodemographic factors, cigarette smoking, and alcohol use. Marijuana use also was not associated with tobacco-related cancers or with cancer of the following sites: colorectal, lung, melanoma, prostate, breast, cervix. Among nonsmokers of tobacco cigarettes, ever having used marijuana was associated with increased risk of prostate cancer (RR = 3.1, CI = 1.0-9.5) and nearly significantly increased risk of cervical cancer (RR = 1.4, CI = 1.0-2.1). We conclude that, in this relatively young study cohort, marijuana use and cancer were not associated in overall analyses, but that associations in nonsmokers of tobacco cigarettes suggested that marijuana use might affect certain site-specific cancer risks.
Article
The complexity of tobacco smoke leads to some confusion about the mechanisms by which it causes lung cancer. Among the multiple components of tobacco smoke, 20 carcinogens convincingly cause lung tumors in laboratory animals or humans and are, therefore, likely to be involved in lung cancer induction. Of these, polycyclic aromatic hydrocarbons and the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone are likely to play major roles. This review focuses on carcinogens in tobacco smoke as a means of simplifying and clarifying the relevant information that provides a mechanistic framework linking nicotine addiction with lung cancer through exposure to such compounds. Included is a discussion of the mechanisms by which tobacco smoke carcinogens interact with DNA and cause genetic changes--mechanisms that are reasonably well understood--and the less well defined relationship between exposure to specific tobacco smoke carcinogens and mutations in oncogenes and tumor suppressor genes. Molecular epidemiologic studies of gene-carcinogen interactions and lung cancer--an approach that has not yet reached its full potential--are also discussed, as are inhalation studies of tobacco smoke in laboratory animals and the potential role of free radicals and oxidative damage in tobacco-associated carcinogenesis. By focusing in this review on several important carcinogens in tobacco smoke, the complexities in understanding tobacco-induced cancer can be reduced, and new approaches for lung cancer prevention can be envisioned.
Article
Taxonomies of alcoholism and antisocial behaviors based on developmental course converge on two-group classifications that emphasize early and late onset. Typologies for users of illicit drugs remain to be developed. This article proposes a developmental taxonomy of marijuana users. Cluster analysis was applied to a representative community sample of 708 (364 male, 344 female) marijuana users followed from adolescence to age 34-35. The Ward method, followed by relocation, was used to classify marijuana users into different types based on age of onset, chronicity of heavy use and persistence of use. ANOVA and logit analyses were utilized to describe the cluster solution and examine the correlates of cluster membership. Four marijuana use clusters were identified: early onset-heavy use, early onset-light use, mid onset-heavy use and late onset-light use. The groups differed from each other in degree of involvement in marijuana and other drugs, sociodemographic and lifestyle characteristics. The majority of those with early onset did not become heavily involved in marijuana. Unique factors were associated with membership in each group. Factors differentiating early from mid-onset heavy use included association with marijuana-using peers and having had a mental disorder. Peer delinquency was an additional factor differentiating early initiators who became heavy users from those who did not. A simple two-type classification fails to take into account the heterogeneity of early and late onset groups. By itself, early onset into marijuana will not lead to problematic use or rapid progression into the use of other drugs. Motivation underlying use and dysfunctional behaviors are associated with the development of problematic drug use and dependence.
Article
To examine the associations between frequency of cannabis use and psychosocial outcomes in adolescence/young adulthood. A 21-year longitudinal study of the health, development and adjustment of a birth cohort of 1265 New Zealand children. Annual assessments of the frequency of cannabis use were obtained for the period from age 14-21 years, together with measures of psychosocial outcomes including property/violent crime, depression, suicidal ideation, suicide attempt and other illicit drug use. The frequency of cannabis use was associated significantly with all outcomes, and particularly other illicit drug use. Statistical control for confounding by both fixed and time-dynamic factors substantially reduced the strength of association between cannabis use and outcome measures. Nevertheless, cannabis use remained significantly (P < 0.05) associated with all outcomes and particularly other illicit drug use, after adjustment for confounding. For the measures of crime, suicidal behaviours and other illicit drug use there was evidence of age related variation in the strength of association with cannabis use, with younger (14-15 years old) users being more affected by regular cannabis use than older (20-21 years old) regular users. However, the association between cannabis use and depression did not vary with age. Cannabis use, and particularly regular or heavy use, was associated with increased rates of a range of adjustment problems in adolescence/ young adulthood-other illicit drug use, crime, depression and suicidal behaviours-with these adverse effects being most evident for school-aged regular users. The findings reinforce public health concerns about minimizing the use of cannabis among school-aged populations.
Article
Purpose: To examine the developmental relationship between adolescent substance use and risky sexual behavior in young adulthood. A gender-balanced, ethnically diverse urban sample of 808 children in Seattle was surveyed at age 10 years in 1985 and followed prospectively to age 21 years in 1996. Semiparametric group-based modeling was used to determine trajectory groups of binge-drinking, cigarette smoking, marijuana use, and the use of other illicit drugs. Negative binomial regressions and logistic regressions were used to examine whether these trajectory groups predicted the number of sex partners and condom use at age 21 years. Specific forms of adolescent substance use significantly predicted risky sexual behavior at age 21 years, after other substance use and early measures of sexual behavior were controlled. Early binge-drinkers had significantly more sex partners than nonbinge-drinkers. Late onset binge-drinkers and marijuana users had significantly more sex partners and were less likely to use condoms consistently than those who did not binge drink or use marijuana. Experimenters in cigarette smoking, who did not escalate smoking, were more likely to use condoms consistently than nonsmokers. In contrast, the use of other illicit drugs in adolescence did not predict risky sexual behavior at age 21 years. The effects of adolescent substance use on risky sexual behavior at age 21 years differed for youths with developmentally different substance use trajectories in this urban sample disproportionately drawn from high crime neighborhoods. To prevent risky sexual behavior among young adults, attention should be paid to binge-drinking and marijuana use during adolescence.
Article
This review describes what is known about effects of marijuana and cannabinoids in relation to human physiological and disease outcomes. The acute physiological effects of marijuana include a substantial dose-dependent increase in heart rate, generally associated with a mild increase in blood pressure. Orthostatic hypotension may occur acutely as a result of decreased vascular resistance. Smoking marijuana decreases exercise test duration in maximal exercise tests, increases the heart rate at submaximal levels of exercise. Tolerance develops to the acute effects of marijuana smoking and delta9-tetrahydrocannibol (THC) over several days to a few weeks. The cardiovascular responses that occur in response to THC are mediated by the autonomic nervous system, with recent findings also demonstrating that the human cannabinoid receptor system plays a role in regulating the cardiovascular response. Although several mechanisms exist by which marijuana use might contribute to the development of chronic cardiovascular conditions or acutely trigger cardiovascular events, there are few data regarding marijuana/THC use and cardiovascular disease outcomes. A large cohort study showed no association of marijuana use with cardiovascular disease hospitalization or mortality. However, acute effects of marijuana use include a decrease of the time until the onset of chest pain in patients with angina pectoris; one study has shown that marijuana may trigger the onset of myocardial infarction. Patients who have coronary heart disease or are at high risk for the development of CHD should be cautioned about the potential hazards of marijuana use as a precipitant for clinical events. Research directions might include more studies of cardiovascular disease outcomes and relationships of marijuana with cardiovascular risk factors, studies of metabolic and physiologic effects of chronic marijuana use that may affect cardiovascular disease risk, increased understanding of the role of the cannabinoid receptor system in cardiovascular regulation, and studies to determine if there is a therapeutic role for cannabinoids in blood pressure control or for neuroprotection after stroke.
Article
Cannabis is the most widely used illegal drug in the U.S. population. Surveys have estimated that the lifetime prevalence rate for cannabis dependence is approximately 4%. Though the presence of a psychiatric disorder increases the likelihood of developing substance dependence, the field lacks data regarding the association between mental disorders and cannabis dependence. The aim of this study is to describe the prevalence of psychiatric disorders among individuals with cannabis dependence. The National Comorbidity Survey was used to obtain these data. We found that 90% of respondents with cannabis dependence had a lifetime mental disorder, compared to 55% without cannabis dependence. Alcohol dependence, antisocial personality disorder, and conduct disorder had the strongest associations with cannabis dependence, followed by anxiety and mood disorders. A large proportion of respondents with internalizing disorders developed mood or anxiety disorders prior to onset of their first cannabis dependence symptom. Data regarding the prevalence of comorbid mental disorders underscore the importance of thorough and systematic evaluation of patients seeking treatment for cannabis dependence. The failure to identify comorbidity may lead to inadequate treatment, and a poorer prognosis.
Article
To examine the evidence on the association between cannabis and depression and evaluate competing explanations of the association. A search of Medline, Psychinfo and EMBASE databases was conducted. All references in which the terms 'cannabis', 'marijuana' or 'cannabinoid', and in which the words 'depression/depressive disorder/depressed', 'mood', 'mood disorder' or 'dysthymia' were collected. Only research studies were reviewed. Case reports are not discussed. There was a modest association between heavy or problematic cannabis use and depression in cohort studies and well-designed cross-sectional studies in the general population. Little evidence was found for an association between depression and infrequent cannabis use. A number of studies found a modest association between early-onset, regular cannabis use and later depression, which persisted after controlling for potential confounding variables. There was little evidence of an increased risk of later cannabis use among people with depression and hence little support for the self-medication hypothesis. There have been a limited number of studies that have controlled for potential confounding variables in the association between heavy cannabis use and depression. These have found that the risk is much reduced by statistical control but a modest relationship remains. Heavy cannabis use and depression are associated and evidence from longitudinal studies suggests that heavy cannabis use may increase depressive symptoms among some users. It is still too early, however, to rule out the hypothesis that the association is due to common social, family and contextual factors that increase risks of both heavy cannabis use and depression. Longitudinal studies and studies of twins discordant for heavy cannabis use and depression are needed to rule out common causes. If the relationship is causal, then on current patterns of cannabis use in the most developed societies cannabis use makes, at most, a modest contribution to the population prevalence of depression.