Tobacco 21 adoption decreased sales of cigarette brands purchased by young people: a translation of population health survey data to gain insight into market data for policy analysis.

Introduction: Policies raising the minimum age of sale of tobacco products to 21 (T21) proliferated at state and local levels across the USA before a federal policy was adopted. Evidence of the effectiveness of these policies is building and lags implementation. This study exploits demographic patterns of cigarette brand purchasing to evaluate the effectiveness of T21.

Methods: To capture the effect of T21 implementation on cigarette sales, we used universal product code-level data from Nielsen Scantrack data covering January 2015 to October 2019. We used the 2015 to 2018 National Survey on Drug Use and Health to identify cigarette brands where smokers under 21 comprised a disproportionately high (young) and low (old) share of consumption. We fit fixed-effects linear regressions in Nielsen designated market areas to test if sales of young or old cigarette brands were changed by T21. Unadjusted models controlled for time and T21 implementation date. Adjusted models controlled for price, seasonality and unemployment. A permutation test of 5000 randomised placebo T21 policies were fit to determine how well the true date of implementation fit sales data stratified by brand group.

Results: Sales of disproportionately young brands declined after T21 implementation. T21 policy implementation dates fit disproportionately young brand sales trends better than 99% of adjusted randomised placebo models. T21 implementation fit disproportionately old brand sales trends better than just 1% of adjusted randomised placebo models.

Conclusion: This study adds compelling empirical evidence that T21 decreased purchases of the cigarette brands consumed disproportionately by young people, the policy's target demographic.