Impact of Smoke-Free Legislation on Acute Myocardial Infarction and Subtypes of Stroke Incidence in Shenzhen, China, 2012–2016: An Interrupted Time Series Analysis*

Abstract

Objective

This study assesses the impact of smoke-free legislation on the incidence rate for acute myocardial infarction (AMI) and stroke in Shenzhen.

Methods

Data on ischemic (n = 72,945) and hemorrhagic (n = 18,659) stroke and AMI (n = 17,431) incidence covering about 12 million people in Shenzhen from 2012 to 2016 were used. Immediate and gradual changes in incidence rates were analyzed using segmented Poisson regression.

Results

Following the smoke-free legislation, a 9% (95% CI: 3%–15%) immediate reduction was observed in AMI incidence, especially in men (8%, 95% CI: 1%–14%) and in those aged 65 years and older (17%, 95% CI: 9%–25%). The gradual annual benefits were observed only in hemorrhagic and ischemic stroke incidence, with a 7% (95% CI: 2%–11%) and 6% (95% CI: 4%–8%) decrease per year, respectively. This health effect extended gradually to the 50–64 age group. In addition, neither the immediate nor gradual decrease in stroke and AMI incidence rates did not show statistical significance among the 35–49 age group (P > 0.05).

Conclusion

Smoke-free legislation was enforced well in Shenzhen, which would generate good experiences for other cities to enact and enforce smoke-free laws. This study also provided more evidence of the health benefits of smoke-free laws on stroke and AMI.