State-Level Flavored E-Cigarette Bans and Initiation Rates Among Youths and Adults.

Importance: The availability of flavored e-cigarettes contributes to adolescent and young adult e-cigarette initiation, exposing users to nicotine and other e-cigarette constituents. In 2020, several US states implemented comprehensive e-cigarette flavor bans to complement the federal e-cigarette flavor enforcement action that applied only to pod-based e-cigarette devices. Objective: To assess the association of state-level e-cigarette flavor bans with e-cigarette initiation across age groups in the US. Design, Setting, and Participants: This cross-sectional study conducted a difference-in-differences analysis accounting for variation in treatment timing using the Population Assessment of Tobacco and Health (PATH) Study survey waves 4 to 7 (January 2017 to April 2023). The PATH Study is an ongoing, nationally representative longitudinal cohort study of tobacco product use among noninstitutionalized US households. Adolescents (ages 12-17 years), young adults (ages 18-24 years), and adults (ages ≥25 years) who reported never using e-cigarettes at a baseline wave and completed the subsequent interview were included. Data were analyzed from January 2024 to June 2025. Exposures: A binary indicator for whether a state flavor ban was enacted as of the first day of the respondent baseline interview quarter. Main Outcomes and Measures: E-cigarette initiation was defined using the PATH Study variable never-to-ever electronic nicotine product user. Results: The study included 72 170 respondents (mean [SD] age, 45 [21] years; 36 893 female [54.4%; 95% CI, 53.7% to 55.5%]; 18 074 Hispanic [16.2%; 95% CI, 15.7% to 16.6%], 10 816 non-Hispanic Black [11.4%; 95% CI, 11.0% to 11.7%], and 34 749 non-Hispanic White [61.5%; 95% CI, 60.9% to 62.2%]). Among young adults, e-cigarette flavor bans were associated with a 6.05-percentage point (95% CI, -11.21 to -0.90 percentage point) decrease in initiation, representing a more than 50% decrease from the preban rate of 70 of 698 young adults (10.9%; 95% CI, 8.3% to 14.1%). However, no significant change was observed among adolescents or adults. Subgroup analyses of the young adult population revealed policy outcomes, as shown by adjusted difference-in-differences estimates, among populations typically considered to experience greater societal advantage, including non-Hispanic White individuals (-7.00 percentage points; 95% CI, -13.81 to -1.19 percentage points), young adults with higher household incomes (annual household income ≥$50 000; -6.92 percentage points; 95% CI, -13.12 to -0.73 percentage points), those without psychosocial distress (no internalizing symptoms: -5.58 percentage points; 95% CI, -11.00 to -0.16 percentage points; no externalizing symptoms: -7.07 percentage points; 95% CI, -12.01 to -2.13 percentage points), and individuals who were not members of sexual minority groups (-6.78 percentage points; 95% CI, -10.68 to -2.87 percentage points). Conclusions and Relevance: In this study, young adults living in states with e-cigarette flavor bans experienced significantly greater declines in e-cigarette initiation compared with those living in control states, but policies were not associated with change among adolescents or young adult subpopulations experiencing some form of societal disadvantage. These findings suggest that additional public health strategies are necessary to reduce adolescent e-cigarette initiation and ensure that current policies equitably benefit all populations.