A decline in the incidence of myocardial infarction (MI), (heart attack) in one Minnesota county appears to be associated with the implementation of smoke-free workplace laws, according to a report published Online First by Archives of Internal Medicine, a JAMA Network publication.

Exposure to secondhand smoke (SHS) is associated with coronary heart disease (CHD) in nonsmokers, and research suggests that the cardiovascular effects of SHS are nearly as large as those with active smoking, according to the study background. Elimination of smoking in public places, such as by smoke-free laws and policies, has the potential for reducing smoking and perhaps cardiovascular events.

Richard D. Hurt, MD, and colleagues at the Mayo Clinic in Rochester, Minnesota, evaluated the incidence of MI and sudden cardiac death (SCD) in Olmsted County, Minnesota during the 18-month period before and after implementation of smoke-free ordinances. In 2002, a smoke-free restaurant ordinance was implemented and, in 2007, all workplaces, including bars, became smoke free.

This study was supported in part by a grant from ClearWay Minnesota, a grant from the National Heart, Lung and Blood Institute/National Institutes of Health and a grant from the National Institute on Aging/National Institutes of Health.

"We report a substantial decline in the incidence of MI from 18 months before the smoke-free restaurant law was implemented to 18 months after the comprehensive smoke-free workplace law was implemented 5 years later," the authors comment.

When comparing the 18 months before implementation of the smoke-free restaurant ordinance with the 18 months after implementation of the smoke-free workplace law, the incidence of MI declined by 33 percent from about 150.8 to 100.7 per 100,000 population, and the incidence of SCD declined by 17 percent from 109.1 to 92 per 100,000 population.

"All people should avoid SHS exposure as much as possible, and those with CHD should have no exposure to SHS, the authors conclude."

In an invited commentary, Sara Kalkhoran, MD and Pamela M. Ling, MD, MPH, of the University of California, San Francisco, write: "The results of the study by Hurt et al highlight some of the potential benefits of 100 percent smoke-free policies in workplaces, restaurants, and bars: significantly decreased incidence of myocardial infarction and a trend toward decreased sudden cardiac death."

"Moving forward, we should prioritize the enforcement of smoke-free policies, eliminating loopholes in existing policies as well as encouraging expansion of smoke-free policies to include multiunit housing, motor vehicles, casinos, and outdoor locations,"they continue.

"Exposure to SHS should not be a condition of employment, and all workers, including those of lower income and those in the service and hospitality industries, should have equal protection from SHS exposure," they conclude.

(Arch Intern Med. Published online October 29, 2012.)