Temporal trends in smoking and nicotine dependence in relation to co-occurring substance use in the United States, 2005–2016

Background: Despite an overall decline in tobacco use in the United States, secular trends of smoking and nicotine dependence with co-occurring substance use are not well characterized. Methods: We examined self-reported tobacco and other substance use in 22,245 participants age 21–59 in the United States from six waves of the National Health and Nutrition Examination Survey (NHANES). Using Joinpoint regression, we assessed secular trends of smoking and nicotine dependence as a function of co-occurring use of alcohol, prescription opioids, marijuana/hashish, cocaine/heroin/methamphetamine, or other injection drug use. Multivariable logistic regressions were fitted to identify the potential risk factors. Results: During 2005–2016, the prevalence of current smoking decreased (without co-occurring substance use: 17.0 %–12.7 %; with co-occurring use of one substance: 35.3 % to 24.6 %; with co-occurring use of two or more substances: 53.8 %–42.2 %), and moderate-to-severe nicotine dependence decreased as well (8.0 %–4.2 %, 16.0 %–8.8 %, and 23.9 %–15.7 %, respectively). Smoking and nicotine dependence were more likely in those with co-occurring use of one substance (current smoking: odds ratio [OR] = 2.22, 95 % confidence interval [CI] = 2.01–2.45); nicotine dependence: OR = 1.88, 95 % CI = 1.63–2.17) and in those with co-occurring use of two or more substances (current smoking: OR = 5.25, 95 % CI = 4.63–5.95; nicotine dependence: OR = 3.24, 95 % CI = 2.72–3.87). Conclusions: Co-occurring substance use was associated with smaller reductions in tobacco use, over time, and with increased odds of nicotine dependence. This suggests that co-occurring substance users should be regarded as a tobacco-related disparity group and prioritized for tobacco control interventions.