Comprehensive Smoke-Free Laws and Cardiovascular Disease Mortality in US Counties.

Importance: Active smoking and secondhand smoke (SHS) exposure are major cardiovascular risk factors, and comprehensive smoke-free laws are a central tobacco control strategy. Although prior studies have demonstrated short-term reductions in cardiovascular morbidity following smoke-free policies, evidence regarding their long-term association with cardiovascular disease (CVD) mortality and potential differences across demographic groups remains limited. Objective: To evaluate the long-term association between comprehensive smoke-free laws and county-level CVD mortality and assess whether these associations vary by age, sex, and race and ethnicity. Design, Setting, and Participants: Comparative effectiveness research study using longitudinal county-level panel data and the generalized synthetic control method to evaluate staggered policy adoption across 38 treated counties that adopted comprehensive 100% smoke-free laws covering workplaces, restaurants, and bars between 2007 and 2018, and 103 control counties that did not implement smoke-free laws at any level during the study period from 2000 to 2018. Data were analyzed from May to August 2025. Exposure: Implementation of comprehensive smoke-free laws. Main Outcome and Measures: Annual county-level age-adjusted CVD mortality rates per 100 000 population overall and stratified by age, sex, and race and ethnicity. Average treatment effects on the treated (ATTs) were estimated with 95% CIs using parametric bootstrapping. Results: This study included 38 treated and 103 control counties. Prepolicy mean (SD) of county-level median age was 37.5 (3.5) for treated counties vs 39.1 (5.6) years for control counties. In treated counties vs control counties, 49.3% vs 49.5% of residents were male, and 15.3% vs 20.3% were not non-Hispanic White, respectively. Implementation of comprehensive smoke-free laws was associated with a mean annual reduction of 12.0 (95% CI, -21.3 to -2.7) CVD deaths per 100 000 population over 12 postpolicy years. Larger reductions were observed among adults aged 65 years or older, male individuals, and non-Hispanic White populations, whereas the associations among younger adults, female individuals, and non-Hispanic Black populations were smaller and less precise. Conclusions and Relevance: In this comparative effectiveness research study of county-level smoke-free laws, comprehensive smoke-free laws were associated with sustained reductions in CVD mortality. However, the magnitude of the associations varied across demographic groups, suggesting that additional strategies addressing disparities in tobacco exposure may be needed to achieve improvement in cardiovascular outcomes across all subpopulations.