State E-Cigarette Flavor Restrictions and Tobacco Product Use in Youths and Adults.

IMPORTANCE

Seven states have policies restricting the sale of flavored e-cigarettes. Limited evidence exists regarding these policies' association with the use of tobacco products across age groups.

OBJECTIVE

To evaluate associations of e-cigarette flavor restriction policies with e-cigarette and cigarette use by age group over multiple years.

DESIGN, SETTING, AND PARTICIPANTS: In this cross-sectional study, annual state-level prevalences of e-cigarette and cigarette use in the US between 2015 and 2023 were separately estimated among youths (high school age) using data from the Youth Risk Behavior Survey (YRBS) and young adults (ages 18-24 years) and adults (ages ≥25 years) using the Behavioral Risk Factor Surveillance System (BRFSS). Six policy states had multiple years of postpolicy data available; other states were control states. Associations between policy and prevalence of e-cigarette and cigarette use in each postpolicy year were estimated annually using difference-in-differences analysis, setting 2019 as the prepolicy year and 2020 to 2023 as postpolicy years.

EXPOSURE

Statewide policy restricting sales of non-tobacco flavored e-cigarettes.

MAIN OUTCOMES AND MEASURES

State annual prevalence of past 30-day (YRBS) and current (BRFSS) e-cigarette and cigarette use.

RESULTS

Prevalence data were obtained for 186 (YRBS) and 386 (BRFSS) state-years for e-cigarettes and 191 (YRBS) and 456 (BRFSS) state-years for cigarettes. In recent years, e-cigarette use prevalence decreased among youths (eg, the change in mean prevalence from 2019 to 2023 was 24.1% to 14.0% for policy states and 24.6% to 17.2% for control states) but increased in control states among young adults (eg, mean prevalence, 17.0% in 2019 to 20.4% in 2023). Cigarette use prevalence decreased in policy and control states, although policy states exhibited lower prepolicy prevalence and attenuated postpolicy decreases (eg, mean prevalence, 6.7% in 2019 to 3.8% in 2023 among young adults) relative to control states (eg, mean prevalence, 12.1% in 2019 to 6.3% in 2023 among young adults). Flavor policies were associated with reduced e-cigarette use among young adults in 2022 (average treatment effect among the treated [ATT], -6.7 percentage points; 95% CI, -1.3 to -12.1 percentage points) and adults aged 25 years or older in 2023 (ATT, -1.2 percentage points; 95% CI, -2.0 to -0.4 percentage points) and increased cigarette use among youths in 2021 (ATT, 1.8 percentage points; 95% CI, 0.7 to 2.9 percentage points) and young adults in 2021 (ATT, 3.7 percentage points; 95% CI, 2.2 to 5.2 percentage points), 2022 (ATT, 2.7 percentage points; 95% CI, 1.4 to 4.1 percentage points), and 2023 (ATT, 3.2 percentage points; 95% CI, 0.9 to 5.5 percentage points).

CONCLUSIONS AND RELEVANCE

In this study, flavor restriction policies were associated with some reductions in e-cigarette use but also unintended increases in cigarette use, highlighting a need for further work evaluating potential substitution outcomes and prevention of tobacco use among youths.