It is now possible to download a copy of the posters that I have presented at research conferences through my CV page.
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Evidence From A Cannabis Use Disorders Multiple Causes Model For The Cannabis-Tobacco Combination Known As ‘Blunts’
This research is part of my PhD dissertation and I presented some preliminary results at the annual College on Problems of Drug Dependence (CPDD) in San Diego, CA on June 17th. The abstract is provided below along with a PowerPoint file of the poster I presented. A link to download the poster can also be found through my CV.
EVIDENCE FROM A CANNABIS USE DISORDERS MULTIPLE CAUSES MODEL FOR THE CANNABISTOBACCO COMBINATION KNOWN AS ‘BLUNTS’.
Brian Fairman, J C Anthony; Department of Epidemiology, Michigan State University, East Lansing, MI
Aims: Globally, cannabis often is combined with tobacco before smoking. In the US, a prevailing cannabis-tobacco combination involves ‘blunts,’ made by substituting cannabis in a hollowed out tobacco cigar. Cannabis users with a history of blunt smoking seem to be at excess risk for cannabis use disorders (CUD). The aim here is to test a hypothesis that the profile of CUD clinical features is determined, in part, by blunt smoking history among cannabis smokers.
Methods: Data are from the nationally representative 2004 US National Survey on Drug Use and Health (NSDUH), with 7054 recent cannabis smokers age 12+ years, all with past-year cannabis use (6+ times), and with valid CUD and lifetime blunt history assessment. Exploratory factor analysis probed CUD latent structure (e.g., 1 v 2 factor model fit). Then, via a multiple indicators, multiple causes model (MIMIC), the blunt smoking effect was estimated for each CUD clinical feature, holding constant CUD level.
Results: Roughly 3/4s of recent cannabis users had smoked blunts at least once. EFA supported a 1-factor solution, and MIMIC modeling disclosed that blunt smoking was independently associated with “tolerance on” and “spending a great deal of time getting/using” cannabis, with CUD level held contstant. Inverse blunt
associations were found for “giving up important activities”, “failure to fulfill roles”, and “continued use despite social problems” under this model (slope estimates: 0.18, 0.41, -0.25, -0.33, and -0.33, respectively; all p-values<0.02).
Conclusions: We discovered that blunt smoking seems to influence CUD clinical features, over and above CUD level. Whether the observed differences indicate substantive differences in blunt effects and/or disclose measurement bias are open questions. Answers to these questions will be needed if we are to make progress in our understanding of the epidemiology of the cannabis-tobacco combination.
Financial Support: NIDA T32DA021129 (BJF); K05DA015799 (JCA).
Publication: Are early-onset cannabis smokers at an increased risk of depression spells?
Fairman, B. J., & Anthony, J. C. (2012). Are early-onset cannabis smokers at an increased risk of depression spells? Journal of Affective Disorders, 138(1-2), 54–62. doi:10.1016/j.jad.2011.12.031
Link to Pubmed
Abstract:
BACKGROUND:
A recent research focus is a set of hypothesized adult-onset mental health disturbances possibly due to early-onset cannabis use (EOCU, onset <18 years). We seek to estimate the suspected EOCU-associated excess odds of experiencing an incident depression spell during adulthood, with comparisons to never cannabis smokers and those with delayed cannabis onset (i.e., not starting to smoke cannabis until adulthood).
METHODS:
The National Surveys on Drug Use and Health (NSDUH) assess non-institutionalized community-dwelling residents of the United States after probability sampling each year. In aggregate, the NSDUH analytical sample included 173,775 adult participants from survey years 2005-2009 (74-76% of designated respondents). Standardized computer-assisted interviews collected information on background determinants, age of first cannabis use, and depression spell onset. Logistic regression was used to estimate EOCU-depression spell associations in the form of odds ratios, with statistical adjustment for sex, age, race/ethnicity, years of cannabis involvement, tobacco cigarette onset, and alcohol onset.
RESULTS:
About 1 in 10 experienced a depression spell during adulthood, and both early-onset and adult-onset cannabis smokers had a modest excess odds of a depression spell compared to never cannabis smokers, even with covariate adjustment (OR=1.7 and 1.8, respectively; both p<0.001). Estimates for early- and adult-onset cannabis smokers did not statistically differ from one another.
LIMITATIONS:
Shared diathesis that might influence both EOCU and adult-onset depression spell is controlled no more than partially, as will be true until essentially all known early-life shared vulnerabilities are illuminated.
CONCLUSION:
Cannabis smoking initiated at any age signals a modest increased risk of a spell of depression in adulthood, even when adjusted for suspected confounding variables studied here. Delaying cannabis onset until adulthood does not appear to diminish the cannabis-associated risk.
Publication: Epidemiological evidence on count processes in the formation of tobacco dependence.
Barondess, D. A., Meyer, E. M., Boinapally, P. M., Fairman, B., & Anthony, J. C. (2010). Epidemiological evidence on count processes in the formation of tobacco dependence. Nicotine & Tobacco Research: Official Journal of the Society for Research on Nicotine and Tobacco, 12(7), 734–741. doi:10.1093/ntr/ntq073
Link to Pubmed
Abstract:
INTRODUCTION:
Large-sample epidemiological studies of tobacco cigarette smoking routinely assess so-called “lifetime prevalence” of tobacco dependence. This work delves into the earliest stages of smoking involvement, focusing on newly incident tobacco cigarette smokers in the very recent past, and examines hypothesized subgroup variation in count processes that become engaged once smoking starts. Here, the term “count process” has two components: (a) whether smoking will be persistent and (b) the rate of smoking, conditional upon membership in a latent class of smokers who will persist, as estimated under the zero-inflated Poisson (ZIP) model for complex survey data.
METHODS:
We estimate these ZIP parameters for nationally representative samples of newly incident smokers in the United States (all with smoking initiation within 24 months of assessment). Data are from the 2004-2007 National Surveys on Drug Use and Health.
RESULTS:
Once cigarette smoking started, roughly 40%-45% persisted, and the estimated median rate was five smoking days/30 days, conditional on membership in the latent class of persistent smokers. Among non-Hispanic recent-onset cigarette smokers, Whites, Black/African Americans, Asians, and Native American/Alaskan Natives did not differ, but recent-onset smokers of Hispanic origin and those of Pacific Islander background had comparatively less cigarette involvement.
DISCUSSION:
Tobacco prevention and control initiatives may require elaboration in the form of brief interventions, including interpersonal and social transactions that might constrain a mounting frequency of days of smoking before daily smoking starts, and until conventional smoking cessation medication aids become indicated. These very-early stage interventions (VESI) might be mounted within family or peer groups or in the primary care or school settings, but randomized trials to evaluate VESI interventions will be required.
Publication: Early cannabis use and estimated risk of later onset of depression spells. Epidemiological evidence from the population-based WHO World Mental Health Survey Initiative
I thought it might be time to update my blog by first posting the citations and abstracts for my current publications, starting in chronological order.
De Graaf, R., Radovanovic, M., van Laar, M., Fairman, B., Degenhardt, L., Aguilar-Gaxiola, S., … Anthony, J. C. (2010). Early cannabis use and estimated risk of later onset of depression spells. Epidemiological evidence from the population-based WHO World Mental Health Survey Initiative. American Journal of Epidemiology, 172(2), 149–159.
Link to Pubmed
Abstract:
Early-onset cannabis use is widespread in many countries and might cause later onset of depression. Sound epidemiologic data across countries are missing. The authors estimated the suspected causal association that links early-onset (age or =17 years) risk of a depression spell, using data on 85,088 subjects from 17 countries participating in the population-based World Health Organization World Mental Health Survey Initiative (2001-2005). In all surveys, multistage household probability samples were evaluated with a fully structured diagnostic interview for assessment of psychiatric conditions. The association between early-onset cannabis use and later risk of a depression spell was studied using conditional logistic regression with local area matching of cases and controls, controlling for sex, age, tobacco use, and other mental health problems. The overall association was modest (controlled for sex and age, risk ratio = 1.5, 95% confidence interval: 1.4, 1.7), was statistically robust in 5 countries, and showed no sex difference. The association did not change appreciably with statistical adjustment for mental health problems, except for childhood conduct problems, which reduced the association to nonsignificance. This study did not allow differentiation of levels of cannabis use; this issue deserves consideration in future research.
