Transitions in state limits on local smoke-free authority: adult smoking patterns across sociodemographic groups.

INTRODUCTION: State smoke-free indoor air (SFIA) preemption laws can restrict smoke-free protections by limiting local authority. This study evaluated whether ending binding SFIA preemption was associated with adult smoking prevalence across sociodemographic groups. METHODS: We analyzed 1996-2023 Behavioral Risk Factor Surveillance System data from states with SFIA preemption histories. Outcomes were respondent-level current and everyday smoking. The exposure was ending venue-specific binding SFIA preemption through repeal or comprehensive statewide smoke-free coverage. We used a staggered-adoption two-stage difference-in-differences quasi-experimental design adjusting for state- and year-fixed effects, respondent characteristics, and time-varying state covariates across workplace, restaurant, bar, and combined-venue regimes. RESULTS: Ending binding SFIA preemption was associated with lower current smoking prevalence across all six regimes (workplace, restaurant, bar, workplace-and-restaurant, bar-and-restaurant, and combined workplace, bar, and restaurant). Average treatment effects for the treated (ATTs) for current-smoking ranged from -0.0080 (95% CI: -0.0123, -0.0002) for workplaces to -0.0118 (95% CI: -0.0177, -0.0073) for the combined workplace, bar, and restaurant regime. Everyday-smoking ATTs were negative across all regimes (range: -0.0030 to -0.0055) but statistically significant only for workplace-and-restaurant (ATT = - 0.0055; 95% CI: -0.0089, -0.0008) and combined workplace, bar, and restaurant regimes (ATT = -0.0050; 95% CI: -0.0101, -0.0023). Current-smoking ATTs ranged from -0.0181 to -0.0218 among adults aged 18-24 years and from -0.0215 to -0.0357 among respondents with less than a high school education. Pre-trend and placebo diagnostics did not provide evidence of differential pre-trends or placebo effects. CONCLUSIONS: Among states with SFIA preemption histories, ending binding SFIA preemption was associated with lower current smoking prevalence among adults. Associations for everyday smoking were more limited, with statistically significant estimates in two combined-venue regimes.