Assessing the overlap between tobacco and marijuana: Trends in patterns of co-use of tobacco and marijuana in adults from 2003–2012

Abstract Background As marijuana legalization and acceptability increase in the U.S., it is important to understand the potential impact on tobacco use. Accordingly, we assessed prevalence, correlates, and ten-year trends in co-use of marijuana and tobacco among U.S. adults. Methods Data came from 378,459 adults participating in the 2003–2012 National Survey on Drug Use and Health, an annual, cross-sectional, household survey. Data from 2011–2012 were used to compute the most recent prevalence of past 30-day marijuana and tobacco use (co-use). Data from 2003–2012 were used to compute demographic correlates of co-use, overall trends in co-use, and trends by age, race, and sex. We also assessed trends in tobacco use among marijuana users and marijuana use among tobacco users. Results From 2011 to 2012, 5.2% of participants were past month co-marijuana and tobacco users, 24.0% were tobacco-only users, and 2.3% were marijuana-only users. From 2003 to 2012, prevalence of co-use increased overall (p < .0001), and among males and females (p < .001, p < .05), those ages 26–34 (p < .001) and 50 + years (p < .0001), and Whites (p < .01), Blacks (p < .05), and Hispanics (p < .01); there were no changes among adults 18–25 years. Tobacco use among marijuana users decreased between 2003 and 2012 (from 74.3% to 69.6%, p < .0001), while marijuana use increased among tobacco users (from 14.2% to 17.8, p < .0001). Conclusions Co-use of tobacco and marijuana increased from 2003–2012, with marijuana use increasing among past-month tobacco users and tobacco use declining among past-month marijuana users. Improved surveillance of co-use is needed as marijuana legalization policies expand and become more integrated in communities.