Effects of E-Cigarette Minimum Legal Sales Ages on Youth Tobacco Use in the United States.

In the United States, individual states established a minimum legal sale age (MLSA) for e-cigarettes between 2010 and 2016 when a federal MLSA came into place. These policies provide a natural experiment from which we can better understand the effect that e-cigarettes have on youth combustible tobacco use. This paper uses National Youth Tobacco Survey data to estimate the effect of the gradual roll-out of e-cigarette MLSAs in the United States on youth e-cigarette use, cigarette use, and cigar use (i.e., cigars, cigarillos, or little cigars). Using an estimator designed to correct for dynamic heterogeneity in treatment effects, e-cigarette MLSAs are estimated to reduce lifetime e-cigarette use by approximately 25% and increase daily cigarette use and daily cigar use by approximately 35%. Therefore, these MLSAs operate as intended in reducing e-cigarette use, although at the expense of more dangerous combustible tobacco use. The Food and Drug Administration should consider the impact of e-cigarette availability in reducing youth combustible tobacco use as an important public health benefit of e-cigarettes in their regulatory activity.