Eric Craig Leas

University of California, San Diego | UCSD · Family Medicine and Public Health

BACKGROUND There is no recognized “gold standard” method for estimating the number of individuals with substance use disorders (SUD) seeking help within a given geographical area. This presents a challenge to policymakers in the effective deployment of resources for the treatment of SUD. Internet search queries related to help-seeking for SUDs may...

Importance: Menthol may make cigarette smoke less aversive and could lead youth to smoke more frequently and become more dependent on nicotine. Objective: To assess the association of menthol use with cigarette smoking frequency and nicotine dependence (ND) among youth cigarettes users. Design, setting, and participants: This cohort study used...

Importance: The inclusion of graphic warning labels (GWLs) on cigarette packs is recommended for tobacco control but has not yet been implemented in the US. It is unknown whether and to what extent the inclusion of GWLs on cigarette packs affects smokers' willingness to display the packs in public. Objective: To determine whether the inclusion o...

OBJECTIVES To identify how the 2017 rapid surge in sales of JUUL e-cigarettes affected usage among US youth and young adults. METHODS Annual surveys in the Population Assessment of Tobacco and Health Study assess tobacco use by product and brand among the US population. We identified 2 cohorts aged 14 to 34 years, 1 with baseline survey in 2014 be...

Migration from Central America to the United States has become a strategy to escape economic poverty, exclusionary state policies and violence for people of Mayan descent. Half of households in the study region have at least one member emigrated to the United States, making “transnational families.” Under the principles Community Based Participator...

Background There is an expanding unregulated market for a psychotropic compound called ∆⁸-Tetrahydrocannabinol (delta-8-THC) that is being derived from hemp, but there are no empirical estimates of public interest in this compound. Methods To measure public interest, we obtained yearly Google query fractions (QFs) that mentioned delta-8-THC (i.e.,...

Introduction Removal of tobacco industry branding from cigarette packs may reduce their appeal. Adding graphic warning labels (GWLs) should enhance this effect. We investigate whether willingness to pay for various packaging designs changes after 3 months’ use of: (1) US branded packs without GWLs (US), (2) non-branded packs without GWLs (Blank), a...

Objective To assess the effectiveness of e-cigarettes in smoking cessation in the USA from 2017 to 2019, given the 2017 increase in high nicotine e-cigarette sales. Methods In 2017, the PATH Cohort Study included data on 3578 previous year smokers with a recent quit attempt and 1323 recent former smokers. Respondents reported e-cigarettes or other...

Background: California Proposition 56 increased cigarette excise tax by $2 per pack with equivalent increases on non-cigarette tobacco products. We estimated the changes in cigarette price, cigarette use, and non-cigarette use following the implementation of Proposition 56 in California in 2017. Methods: Seven waves of Tobacco Use Supplements to...

Importance: Although e-cigarettes are not approved as a cessation device, many who smoke believe that e-cigarettes will help them quit cigarette smoking successfully. Objective: To assess whether people who recently quit smoking and who had switched to e-cigarettes or another tobacco product were less likely to relapse to cigarette smoking compa...

To the Editor I read with interest the difference-in-differences analysis of youth smoking and a ban on sales of flavored tobacco products in San Francisco, California, by Friedman.¹ While I believe the article presents a hypothesis worthy of scientific study, there are 2 main reasons I believe the conclusions drawn from this study should be temper...

Objective To identify whether three types of cigarette pack designs, including three versions of graphic warning label (GWL) plain packs, one GWL absent and branding absent pack (blank) and the smoker’s own GWL absent and branding present pack (US), elicit different valence, type and levels of affect. Design US daily smokers (n=324) were asked to...

Background The coronavirus disease (COVID-19) pandemic has impacted patients receiving methadone maintenance treatment (MMT) through opioid treatment programs (OTPs), especially because of the unique challenges of the care delivery model. Previously, documentation of patient experiences during emergencies often comes years after the fact, in part b...

Introduction: This study examined the predictive relationships between biomarkers of nicotine exposure and 16-item self-reported level of tobacco dependence (TD) and subsequent tobacco use outcomes. Methods: The Population Assessment of Tobacco and Health (PATH) Study surveyed adult current established tobacco users who provided urine biospecime...

Importance The US Food and Drug Administration’s implementation of graphic warning labels (GWLs) on cigarette packs is under challenge in US courts. Objective To determine whether GWLs can affect US smokers’ perceptions about their cigarettes or health consequences and changes in smoking behavior. Design, Setting, and Participants This study was...

Objectives To estimate the effect of menthol use and transitions in use (switching to or from menthol) on short-term and long-term cessation from cigarette smoking and whether this differed across demographic groups (age, sex, race). Methods We compared the probability of 30+ day and 12-month abstinence from cigarette smoking by menthol use status...

Vaping products containing cannabidiol (CBD), a cannabis-derived compound used in wellness products and available in all 50 US states, were recently implicated in outbreaks of poisonings. Little is known about the commercial availability of CBD products in vape shops (i.e., stores that sell e-cigarettes). To document the availability and marketing...

Background Public health is increasingly turning to non-traditional digital data to inform HIV prevention and control strategies. We demonstrate a parsimonious method using both traditional survey and internet search histories to provide new insights into HIV testing and pre-exposure prophylaxis (PrEP) information seeking that can be easily extende...

Objectives To assess whether the late 2019 US outbreak of pulmonary disease linked to vaping (‘E-cigarette, or Vaping, product use Associated Lung Injury’ (EVALI)) impacted online shopping queries for vaping products and the Philip Morris ‘IQO’ brand of heated tobacco. Methods We tracked online shopping queries for vape(s), JUUL and IQOS by analys...

Objectives: To identify predictors of becoming a daily cigarette smoker over the course of 4 years. Methods: We identified 12- to 24-year-olds at wave 1 of the US Population Assessment of Tobacco and Health Study and determined ever use, age at first use, and daily use through wave 4 for 12 tobacco products. Results: Sixty-two percent of 12- t...

Background The accuracy of statistical reporting that informs medical and public health practice has generated extensive debate, but no studies have evaluated the frequency or accuracy of effect size (the magnitude of change in outcome as a function of change in predictor) reporting in prominent health journals. Objective To evaluate effect size r...

We investigated how intelligent virtual assistants (IVA), including Amazon’s Alexa, Apple’s Siri, Google Assistant, Microsoft’s Cortana, and Samsung’s Bixby, responded to addiction help-seeking queries. We recorded if IVAs provided a singular response and if so, did they link users to treatment or treatment referral services. Only 4 of the 70 help-...

Introduction This study compared tobacco use and cessation for African Americans (AA), Asians/Pacific Islanders (API), Hispanics/Latinos (H/L), American Indian/Alaskan Natives (AI/AN), and non-Hispanic Whites (NHW) in the United States (US) to California (CA), the state with the longest continually funded tobacco control program. The purpose of thi...

Background The death of George Floyd while in police custody has resurfaced serious questions about police conduct that result in the deaths of unarmed persons. Objective Data-driven strategies that identify and prioritize the public’s needs may engender a public health response to improve policing. We assessed how internet searches indicative of...

Importance Use of cannabidiol (CBD) has markedly increased in the past 5 years, concurrent with marketing claims that over-the-counter CBD can be used to treat almost any health condition. However, the reasons why individuals use CBD remain unclear. Objective To assess whether individuals are using CBD for diagnosable conditions that have evidence...

Background. Public health is increasingly turning to non-traditional digital data to inform HIV prevention and control strategies. We demonstrate a parsimonious method using both traditional survey and internet search histories to provide new insights into HIV testing and pre-exposure prophylaxis (PrEP) information seeking that can be easily extend...

Background In the latter half of 2019, an outbreak of pulmonary disease in the USA resulted in 2807 hospitalisations and 68 deaths, as of 18 February 2020. Given the severity of the outbreak, we assessed whether articles during the outbreak era more frequently warned about the dangers of vaping and whether internet searches for vaping cessation inc...

Background: The US lags behind >120 countries in implementing graphic warning labels (GWLs) on cigarette packs. US courts prevented implementation of FDA's 2012 rule requiring GWLs citing the need for more evidence on effectiveness. After more research, in 2020, the FDA proposed a revised rule mandating GWLs. This trial will test how the introduct...

E-cigarettes are the preferred smoking-cessation aid in the US, however there is little evidence regarding long-term effectiveness among those who use them. We used the Population Assessment of Tobacco and Health Study to compare long-term abstinence between matched US smokers who tried to quit with and without use of e-cigarettes as a cessation ai...

BACKGROUND The death of George Floyd while in police custody has resurfaced serious questions about police conduct that result in the deaths of unarmed persons. OBJECTIVE Data-driven strategies that identify and prioritize the public’s needs may engender a public health response to improve policing. We assessed how internet searches indicative of...

Instagram, with more than 1 billion monthly users, is the go-to social media platform to chronicle one’s life via images, but how are people using the platform to present visual content about HIV? We analyzed public Instagram posts containing the hashtag “#HIV” (because they are self-tagged as related to HIV) between January 2017 and July 2018. We...

Reducing tobacco use is an important public health objective. It is the largest preventable cause of death and disease, yet inequalities remain. This study examines combined educational and racial/ethnic disparities in the United States related to cigarette smoking for the three largest racial/ethnic groups (African Americans, Hispanics/Latinos, an...

Ask the Doctor (AtD) services provide patients the opportunity to seek medical advice using online platforms. While these services represent a new mode of healthcare delivery, study of these online health communities and how they are used is limited. In particular, it is unknown if these platforms replicate existing barriers and biases in tradition...

Background and aims Building on published work¹ establishing concurrent validity of a self-report tobacco dependence (TD) index among users of different tobacco products in Wave 1 (W1) of the Population Assessment of Tobacco and Health (PATH) Study, the current study examines prospective relationships with tobacco use behaviors to establish predict...

Ask the Doctor (AtD) services provide patients the opportunity to seek medical advice using online platforms. While these services represent a new mode of healthcare delivery, study of these online health communities and how they are used is limited. In particular, it is unknown if these platforms replicate existing barriers and biases in tradition...

People’s perceptions about health risks, including their risk of acquiring HIV, are impacted in part by who they see portrayed as at risk in the media. Viewers in these cases are asking themselves “do those portrayed as at risk look like me?” An accurate perception of risk is critical for high-risk populations, who already suffer from a range of he...

Although many studies document the use of social media for sharing and requesting information on specific health conditions,¹,2 whether individuals obtain diagnoses on social media platforms has not been investigated.³,4 The occurrence of requests for a diagnosis on social media (crowd-diagnosis) and determination as to whether the requested diagno...

To the Editor We applaud Niederkrotenthaler and colleagues¹ for adding another layer of evidence that 13 Reasons Why is harming the public by pushing some individuals toward suicide. However, their dismissal of some of the earliest evidence on this subject deserves a revision not because it undermines their central claim but because it makes it eve...

BACKGROUND Instagram, a photo- and video-sharing social networking site, is a popular platform for sharing self-described health- and wellness-related content that is searchable by hashtags. People’s perceptions of health risks may be affected by what they view on social media. As a result, it is important to understand how content promoting HIV pr...

A national for-profit marijuana industry is expanding substantially in the United States. Thirty-three states have legalized medical marijuana, 10 of which (where 1 in 4 individuals reside) have also legalized recreational marijuana. Sales of marijuana are projected to increase from $8.5 billion to $75 billion by 2030, rivaling current tobacco sale...

In the US, youth attribute higher levels of harm and addictiveness to cigarettes relative to other tobacco products. Monitoring harm perceptions across a range of tobacco products is important when forecasting risk for experimentation. This study examined data from US youth (N = 10,081) ages 12–17 from the Population Assessment of Tobacco and Healt...

Achieving universal health and well-being for all Americans is the ideal goal for US public health efforts, but inequities in chronic disease and life expectancy present a persistent challenge, particularly in large cities.¹ In 2016, the Robert Wood Johnson Foundation and the US Centers for Disease Control and Prevention launched the 500 Cities Pro...

News media monitoring is an important scientific tool. By treating news reporters as data collectors and their reports as qualitative accounts of a fast changing public health landscape, researchers can glean many valuable insights. Yet, there have been surprisingly few innovations in public health media monitoring, with nearly all studies relying...

Pharmacies face increasing pressure to abandon tobacco sales, as CVS Health did in September 2014.¹ Although selling tobacco, the leading cause of preventable death and cardiovascular disease, is incongruous with promoting health and wellness, tobacco sales in pharmacies totaled almost $5 billion in 2012.² At one pharmacy chain, approximately 1 in...

Many smokers believe that electronic nicotine delivery systems (ENDS) and pharmaceutical cessation aids can help them quit smoking or reduce cigarette consumption, but the evidence for e-cigarettes to aid quitting is limited. Examining 3,093 quit attempters in the nationally-representative US Population Assessment of Tobacco and Health (PATH) Study...

Importance Cigarette marketing contributes to initiation of cigarette smoking among young people, which has led to restrictions on use of cigarette advertising. However, little is known about other tobacco advertising and progression to tobacco use in youth and young adults. Objective To investigate whether receptivity to tobacco advertising among...

In the early 1990s, a series of randomized trials demonstrated the efficacy of both pharmaceutical aids with behavioral therapy for smoking cessation and treatments for metastatic breast cancer. These treatments were approved by the US Food and Drug Administration and quickly disseminated into clinical practice. A decade later, the population mean...

Background: Despite strong efficacy in randomized trials, the population effectiveness of pharmaceutical aids in long-term smoking cessation is lacking, possibly because of confounding (factors that are associated with both pharmaceutical aid use and difficulty quitting). Matching techniques in longitudinal studies can remove this confounding bias...

Background Over two-thirds of Natural American Spirit (NAS) smokers believe their cigarettes might be ‘less harmful’, but toxicological evidence does not support this belief. We assessed whether standardised packaging could reduce the possibility of erroneous inferences of ‘safety’ drawn from NAS cigarette packaging. Methods US adult smokers (n=90...

Social media may provide new opportunities to promote skin cancer prevention, but research to understand this potential is needed. In April of 2015, Kentucky native Tawny Willoughby (TW) shared a graphic skin cancer selfie on Facebook that subsequently went viral. We examined the volume of comments and shares of her original Facebook post; news vol...

Heat-not-burn tobacco products, battery powered devices that heat leaf tobacco to approximately 500 degrees Fahrenheit to produce an inhalable aerosol, are being introduced in markets around the world. Japan, where manufacturers have marketed several heat-not-burn brands since 2014, has been the focal national test market, with the intention of dev...

The Netflix series 13 Reasons Why explores the suicide of a fictional teen, and the finale graphically shows the suicide over a 3-minute scene.

Background and objectives: Non-cigarette tobacco marketing is less regulated and may promote cigarette smoking among adolescents. We quantified receptivity to advertising for multiple tobacco products and hypothesized associations with susceptibility to cigarette smoking. Methods: Wave 1 of the nationally representative PATH (Population Assessme...

One in eight of the 1.2 million Americans living with human immunodeficiency virus (HIV) are unaware of their positive status, and untested individuals are responsible for most new infections. As a result, testing is the most cost-effective HIV prevention strategy and must be accelerated when opportunities are presented. Web searches for HIV spiked...

The purpose of this study was to investigate susceptibility and ever use of tobacco products among adolescents and young adults in the US. Cross-sectional analysis of Wave 1(2013-2014) adolescent (12-17year-olds; n=13,651) and young adult (18-24year-olds; n=9112) data from the nationally-representative Population Assessment of Tobacco and Health (P...

Background This study extends research on receptivity to tobacco marketing over a key developmental period for cigarette smoking experimentation. PurposeThe purpose of this study was to understand the effect of receptivity to tobacco marketing and exposure to friends who smoke on smoking experimentation. Methods Participants were 10 to 13 years old...