A decline in heart attacks in one Minnesota county appears to be linked to smoke-free workplace laws, according to a new report in Archives of Internal Medicine.

According to a release from the journal, which published the study online last week, exposure to secondhand smoke is associated with coronary heart disease in non-smokers, and research suggests the cardiovascular effects of secondhand smoke are nearly as large as those with active smoking.

Richard D. Hurt, a Mayo Clinic physician, and his Mayo colleagues in Rochester, Minn., evaluated the incidence of heart attack and sudden cardiac death in Olmsted County, Minn., 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.

"We report a substantial decline in the incidence of (heart attack) from 18 months before the smoke-free restaurant law was implemented to 18 months after the comprehensive smoke-free workplace law was implemented five years later," the authors said.

In the 18 months following implementation of the smoke-free workplace law, heart attack incidence declined 33 percent - from about 150.8 to 100.7 per 100,000 population - from the same period before the law went into effect.

The study was supported in part by a grant from ClearWay Minnesota, a nonprofit that tries to cut tobacco use; a grant from the National Heart, Lung and Blood Insti-tute/National Institutes of Health; and a grant from the National Institute on Aging/National Institutes of Health.

Karen Palmersheim, a researcher with the University of Wisconsin-Milwaukee's Center for Urban Initiatives and Research, said that organization is considering a study similar to the Minnesota one, using statewide data.

Laura Smith, communications specialist with SmokeFree Wisconsin, said the Minnesota smoke-free law is "pretty similar" to Wisconsin's.