Objective: We investigated whether recreational marijuana legalization (RML) in Oregon in 2015 and recreational marijuana and alcohol retail outlet density levels in Oregon counties were associated with increased alcohol and marijuana co-use and beliefs supportive of alcohol and marijuana use among adolescents. Method: We conducted secondary analyses of biennial data collected from 11th graders who participated in the Student Wellness Survey (SWS) in 36 Oregon counties from 2010 to 2018 (N = 71,870). Multi-level logistic regression analyses assessed changes in past-30-day co-use of alcohol and marijuana, and alcohol- and marijuana-related beliefs after RML in counties with low, medium, and high densities of licensed recreational marijuana and alcohol retail outlets. We used post-RML 2016 and 2018 SWS data to examine whether beliefs accounted for any relationship of recreational marijuana and alcohol outlet density with alcohol and marijuana co-use. Results: We found a significant post-RML increase in past-30-day alcohol and marijuana co-use in 2016 in counties with the highest density of recreational marijuana and alcohol retail outlets. There were significant post-RML increases in perceived risk and parent approval of alcohol and marijuana use. Analyses with 2016 and 2018 SWS data indicated that the relationship between level of recreational marijuana and alcohol retail outlet density and past-30-day alcohol and marijuana co-use was accounted for beliefs about marijuana and alcohol availability, approval by parents, and risk. Conclusion: RML and greater retail availability of recreational marijuana and alcohol were positively associated with alcohol and marijuana co-use among adolescents, and with beliefs favorable to alcohol and marijuana use.

Objective A California, USA, law raised the minimum tobacco sales age to 21 (T21) on 9 June 2016. We investigated whether T21 was associated with reductions adolescents’ use of tobacco cigarettes, smokeless tobacco and electronic cigarettes and whether these associations differed across racial and ethnic groups. Methods Secondary analyses of data from 2 956 054 7th, 9th and 11th grade students who participated in the California Healthy Kids Survey from 2010–11 to 2017–2018. Results Multilevel mixed effects logistic regression analyses showed that T21 was associated with reduced prevalence of lifetime smokeless tobacco and e-cigarette use and past month smokeless tobacco use in the overall student population. T21 was associated with increases in prevalence of past month e-cigarette use. Moderation analyses indicated differences by racial and ethnic groups. Notably, T21 was associated with reductions in lifetime and past 30-day use of all tobacco and nicotine products among Latinx youth. The findings were more mixed for other racial and ethnic groups. Slopes analyses indicated that T21 was associated with accelerated downward trends for 30-day cigarette and smokeless use; moderated trends for lifetime cigarette smoking such that downward slopes became less steep; and reversed downward trends for e-cigarette use. Changes in slopes varied across racial and ethnic groups. Conclusions Our findings highlight the importance of understanding the complex associations that T21 and other tobacco control policies have with the use of different tobacco and nicotine products among racial and ethnic groups. Future research should investigate mechanisms underlying these differences to inform tobacco control efforts.

In 2016, California enacted a law (T21) prohibiting tobacco product sales to individuals under 21 years of age. Given tobacco use disparities among sexual minority (SM) youth, this study investigated whether California’s T21 law was differentially associated with changes in tobacco use for SM and non-SM adolescents. Secondary analyses of California Healthy Kids Survey data from 2013–2014 to 2018–2019 for 7th, 9th, and 11th graders (N = 2 229 401). Multilevel mixed-effects logistic regression analyses showed that SM students were more likely than non-SM students to report past-30-day and lifetime cigarette (odds ratio (OR) = 2.47; OR = 2.37), e-cigarette (OR = 1.21; OR = 1.10), smokeless tobacco use (OR = 1.95; OR = 1.56), and use of any tobacco product (OR = 1.94; OR = 1.61). Among SM youth, T21 was associated with significant reductions in lifetime e-cigarette use (OR = 0.66), and lifetime use of any tobacco products (OR = 0.75). These decreases generally were greater than or equivalent to those observed for non-SM youth. For 30-day e-cigarette and any tobacco use, SM youth showed no significant increases, whereas non-SM youth showed significant increases (OR = 1.06; OR = 1.11) following T21. T21 was associated with smaller increases in lifetime cigarette use (OR = 1.34), and larger increases for past-30-day and lifetime smokeless tobacco use (OR = 1.34; OR = 1.28) among SM students, to those observed for non-SM students. California’s T21 policy may help reduce tobacco use disparities among SM students who are more at risk for tobacco use than their non-SM peers. Research on associations of T21 laws with tobacco use among sexual minority (SM) adolescents is lacking. The potential for unintended consequences of T21 for these adolescents raises concerns about increased health disparities. Importantly, our study generally found California’s T21 was associated with reductions in tobacco use among SM students that were equivalent to or greater than those for non-SM students. Future research should investigate whether T21 laws and similar policies have differential effects for other marginalized groups and, if so, identify mechanisms that can be targeted in prevention efforts.