Reductions in admissions for myocardial infarction (MI) have been reported in locales where smoke-free workplace laws have been implemented, but no study has assessed sudden cardiac death (SCD). In 2002, a smoke-free restaurant ordinance was implemented in Olmsted County, Minnesota, and in 2007, all workplaces including bars became smoke free.
To evaluate the population impact of smoke-free laws, we measured, through the Rochester Epidemiology Project, the incidence of MI and SCD in Olmsted County during the 18-month period before and after implementation of each smoke-free ordinance. All MIs were continuously abstracted and validated using rigorous standardized criteria relying on biomarkers, cardiac pain, and Minnesota coding of the electrocardiogram. SCD was defined as out-of-hospital deaths assigned to coronary disease.
Comparing the 18 months before the implementation of the smoke-free restaurant ordinance to the 18 months after the implementation of the smoke-free workplace law, the incidence of MI declined by 33% (P<0.01) from 150.8 to 100.7 per 100,000 population, and the incidence of SCD declined by 17% (P=0.13) from 109.1 to 92.0 per 100,000 population. During the same period, the prevalence of smoking declined while that of hypertension, diabetes, hypercholesterolemia, and obesity either remained constant or increased.
A substantial decline in the incidence of MI was observed after smoke-free laws were implemented, the magnitude of which is not explained by community co-interventions or changes in cardiovascular risk factors with the exception of smoking prevalence. As trends in other risk factors do not appear explanatory, smoke-free workplace laws seem ecologically related to these favorable trends. Secondhand smoke (SHS) exposure should be considered a modifiable risk factor for MI. All people should avoid SHS to the extent possible, and people with known coronary heart disease should have no exposure to SHS.