Comprehensive E-Cigarette Flavor Bans and Tobacco Use Among Youth and Adults.

The vast majority of youth e-cigarette users consume flavored e-cigarettes, raising concerns from public health advocates that flavors may drive youth initiation and continued use of e-cigarettes. Flavors drew further notice from the public health community following the sudden outbreak of lung injury among vapers in 2019, prompting several states to enact sweeping bans on flavored e-cigarettes. In this study, we examine the effects of these comprehensive bans on e-cigarette use and potential spillovers into other tobacco use by youth, young adults, and adults. We utilize both standard difference-in-differences (DID) and synthetic DID methods, in conjunction with four national data sets. We find evidence that young adults decrease their use of e-cigarettes by about two to three percentage points, while increasing cigarette use. For youth, there is some suggestive evidence of increasing cigarette use, though these results are undermined by pre-trend differences between treatment and control units. The bans have no effect on e-cigarette and smoking participation among adults 25 and over. Our findings suggest that statewide comprehensive flavor bans may have generated an unintended consequence by encouraging substitution toward traditional smoking in some populations.