Abstract
INTRODUCTION: Smoking and secondhand smoke are major global health threats, significantly contributing to the burden of ischemic heart disease (IHD). Despite the implementation of tobacco control policies worldwide, limited evidence exists on the health impacts in Shanghai. This study evaluates the effects of Shanghai's 2017 smoke-free legislation on IHD hospitalization and mortality rates. METHODS: We conducted Interrupted Time Series (ITS) method to analyze monthly data on IHD hospitalizations and mortality among registered residents of Shanghai from July 2013 to December 2021. Age-standardized rate, Poisson and negative binomial regression models were performed to control for covariates. RESULTS: We included 898535 hospitalizations and 180658 deaths caused by IHD from July 2013 to December 2021 in Shanghai. Following policy implementation, there was a significant immediate increase (β=8.29; 95% CI: 2.45-14.13) and post-trend decline (β= -0.73; 95% CI: -0.93 - -0.54) in IHD hospitalization, which is estimated to have prevented approximately 890 hospitalizations per year. Subgroup analysis revealed that the long-term decrease was more pronounced in individuals aged ≥65 years (β= -1.72; 95% CI: -2.21 - -1.24), compared to those aged 35-64 years (β= -0.33; 95% CI: -0.42 - -0.25). However, mortality rates showed no statistically significant immediate (β= -0.90, 95% CI: -4.76-2.95) or long-term changes (β= -0.0075; 95% CI: -0.14-0.12). CONCLUSIONS: Shanghai's comprehensive smoke-free legislation appears to be associated with a significant long-term reduction in hospitalization rates and a modest decrease in mortality rates from ischemic heart disease, particularly among older adults. These findings support the potential cardiovascular health benefits of smoke-free policies, which provide useful evidence for other cities considering the adoption or reinforcement of comprehensive public smoking bans to help reduce the burden of cardiovascular disease and improve population health.