Comprehensive state smoke-free policies as a predictor of cognitive impairment among older Americans: the Health and Retirement Study.

INTRODUCTION: Exposure to secondhand smoke is an important risk factor for cognitive impairment. This study aimed to investigate the associations between statewide comprehensive smoke-free policies and cognitive impairment among older Americans.

METHODS: Using a difference-in-differences approach, we analysed data in a US nationally representative sample of adults aged 51 and older collected between 1998 and 2020 from the Health and Retirement Study. We compared the risk of cognitive impairment among older adults living in states with and without statewide comprehensive 100% smoke-free policies that prohibit smoking in workplaces, restaurants and bars.

RESULTS: In an adjusted difference-in-differences model, we found that implementing statewide comprehensive smoke-free policies was associated with a 1.6 percentage point decrease in the probability of cognitive impairment among older adults (95% CI -2.4 to -0.7; p<0.001). A similar beneficial association was observed among non-smoking older adults but not among older adults who reported currently smoking cigarettes before the policy implementation.

CONCLUSION: Our findings suggest that statewide comprehensive smoke-free policies could potentially serve as population-level interventions to reduce the risk of cognitive impairment.