Tobacco-21 laws and young adult smoking: quasi-experimental evidence.
Friedman AS., Buckell J., Sindelar JL.
AIMS:To estimate the impact of tobacco-21 laws on smoking among young adults who are likely to smoke, and consider potential social multiplier effects. Design Quasi-experimental, observational study using new 2016-17 survey data. SETTING:United States. PARTICIPANTS/CASES:A total of 1869 18-22-year-olds who have tried a combustible or electronic cigarette. INTERVENTION AND COMPARATORS:Tobacco-21 laws raise the minimum legal sales age of cigarettes to 21 years. Logistic regressions compared the association between tobacco-21 laws and smoking among 18-20-year-olds with that for 21-22-year-olds. The older age group served as a comparison group that was not bound by these restrictions, but could have been affected by correlated factors. Age 16 peer and parental tobacco use were considered as potential moderators. MEASUREMENTS:Self-reported recent smoking (past 30-day smoking) and current established smoking (recent smoking and life-time consumption of at least 100 cigarettes). FINDINGS:Exposure to tobacco-21 laws yielded a 39% reduction in the odds of both recent smoking [odds ratio (OR) = 0.61; 95% confidence interval (CI) = 0.42, 0.89] and current established smoking (OR = 0.61; 95% CI = 0.39, 0.97) among 18-20-year-olds who had ever tried cigarettes. This association exceeded the policy's relationship with smoking among 21-22-year-olds. For current established smoking, the tobacco-21 reduction was amplified among those whose closest friends at age 16 used cigarettes (OR = 0.50; 95% CI = 0.29, 0.87), consistent with peer effects moderating the policy's impact on young adult smoking. CONCLUSIONS:Tobacco-21 laws appear to reduce smoking among 18-20-year-olds who have ever tried cigarettes.