Marijuana use by middle-aged and older adults in the United States, 2015-2016

Background: Marijuana use is increasing among middle-aged and older adults in the US, but little is understood of its pattern of use by this population. Methods: We performed a cross-sectional analysis of responses from 17,608 adults aged >= 50 years from the 2015 and 2016 administrations of the National Survey on Drug Use and Health. Prevalence of past-year marijuana use was estimated and compared between middle-aged adults (age 50-64) and older adults (>= 65). Characteristics of past-year marijuana users including demographics, substance use, chronic disease, and emergency room use, were compared to non-marijuana users and stratified by age group. Marijuana use characteristics were also compared between middle-aged and older adults. We used multivariable logistic regression to determine correlates of past-year marijuana use. Results: Prevalence of past-year marijuana use was 9.0% among adults aged 50-64 and 2.9% among adults aged >= 65. Prevalence of past-year alcohol use disorder (AUD), nicotine dependence, cocaine use, and misuse of prescription medications (i.e., opioids, sedatives, tranquilizers) were higher among marijuana users compared to non-users. In adjusted models, initiation of marijuana use < 19 years of age [adjusted odds ratio (AOR) = 13.43, 95% confidence interval (Cl) 9.60, 18.78)1, AUD (AOR = 2.11, 95% Cl 1.51, 2.94), prescription opioid misuse (AOR 2.49, 95% CI 1.61, 3.85), nicotine dependence (AOR = 1.90, 95% Cl 1.59, 2.26), and cocaine use (AOR 7.43, 95% Cl 4.23, 13.03), were all associated with increased odds of past-year marijuana use. Conclusion: Marijuana use is becoming more prevalent in this population and users are also at high risk for other drug use.