A decline in the number of cases of myocardial infarction, or heart attack, in one Minnesota county appears linked to smoke-free workplace laws in that area, research published Monday in the Archives of Internal Medicine finds.

(Karen Bleier/AFP/Getty Images)

They also found a smaller decline (17 percent) in cases of sudden cardiac death between the two periods. The study observes that sudden cardiac deaths have generally declined over the past few decades, but that the decline in such deaths detected in this study was sharper than that trend would predict.

The study attributes the decline in myocardial infarction largely to the reduced exposure to secondhand smoke (SHS), even as prevalence of other risk factors for coronary heart disease such as obesity and diabetes increased, and that of hypertension and high cholesterol remained steady between the two periods studied. On the other hand, the prevalence of active smoking, another key risk factor, declined between the study periods, perhaps in part because of the new laws, the study suggests.

The authors explain that their study adds to the growing body of knowledge regarding the detrimental health effects of SHS, which can damage the cardiovascular system with alarming rapidity and which, they note, can be as harmful as active smoking. “The impact of smoke-free legislation is multifold: reducing the intensity of smoking among smokers, increasing quit rates, reducing smoking startup by teenagers, and reducing exposure to SHS,” the authors wrote.

An accompanying editorial calls for expansion of smoke-free laws to encompass all kinds of public spaces – including multi-unit housing complexes, parks and other outdoor venues -- and all workplaces, particularly those such as casinos and service industries in which low-income and minority employees are subjected to second-hand smoke.