Interaction Between State-Level Cigarette Prices and County-Level Tobacco 21 Coverage on Cigarette Smoking Outcomes Among US Adolescents.

Purpose: To examine whether Tobacco 21 (T21) law coverage moderated associations between cigarette prices and adolescent smoking and associated disparities.

Methods: We used nationally representative, repeated cross-sectional 2014-2020 Monitoring the Future study data (n = 20,547-96,083) to examine associations between state-level average cigarette price per pack and county-level T21 coverage (100% vs. < 100%) on past 30-day smoking participation, first and daily cigarette smoking initiation, and smoking intentions in US adolescents in eighth, 10th, and 12th grade. We implemented weighted, grade-stratified, modified Poisson regression models to test for interactions between price and T21 coverage for each outcome. We also tested for disparities by sex, race and ethnicity, parental education, and college educational expectations.

Results: Higher cigarette prices were associated with a lower probability of past 30-day smoking participation among eighth graders in counties with < 100% T21 coverage (average marginal effect = -0.003, 95% confidence interval = -0.006, 0.000) but not among eighth graders in counties with 100% T21 coverage (average marginal effect = 0.001, 95% confidence interval = -0.001, 0.004) (p for interaction = 0.005). There were no associations with other smoking outcomes or grades or evidence of differential associations by sociodemographic factors.

Discussion: Our findings suggested that higher cigarette prices were associated with lower adolescent smoking among eighth graders living in counties with < 100% T21 coverage. However, no such association was observed in other grades or smoking outcomes. Further investigation is necessary to determine the best combination of policies to reduce adolescent smoking, related sociodemographic disparities, and the use of other tobacco products in areas with fewer tobacco control policies.