Regional bans on smoking in public places may decrease hospital admission rates for acute myocardial infarctions in nonsmokers by as much as 70 percent, according to an article in the third quarter issue of Journal of Drug Education.

In the current study, U.S. researchers at Indiana University Bloomington found that after a countywide smoking ban was implemented, hospital admissions dropped significantly for nonsmokers, but not for smokers.

"Heart attack admissions for smokers saw no similar decline during the study, so the benefits of the ban appear to come more from the reduced exposure to second-hand smoke among non-smokers than from reduced consumption of tobacco among smokers," said Dong-Chul Seo, lead author and an assistant professor in IU Bloomington's Department of Applied Health Science.

The study was the first to examine the effect of public smoking bans on infarctions in non-smokers. Previous studies did not distinguish between non-smokers and smokers when examining the effect of the bans or specifically look at non-smokers who had no risk factors for heart disease, such as hypertension, high cholesterol, or previous heart surgery.

Exposure to second-hand smoke for just 30 minutes can rapidly increase a person's risk for myocardial infarction, even if they have no risk factors. The smoke, which contains carbon monoxide, causes blood vessels to constrict and reduces the amount of oxygen that can be transported in the blood.

"What concerns us is the fact that about half of all non-smoking Americans are regularly exposed to second-hand smoke, even though more than 500 municipalities nationwide have adopted some form of a smoking ban in public places," said Seo, whose research interests include smoking and obesity prevention.

Researchers examined hospital admissions for acute myocardial infarction in Monroe County, Ind., and Delaware County, Ind., which are comparable in a number of ways, including population, presence of a college community, median income, racial/ethnic diversity and heart disease death rates. Delaware County had no smoking bans during the study period, while Monroe County prohibited smoking in restaurants, bars, retail spaces and workplaces.

The study compared the two counties in addition to analyzing the 35,482 hospital admissions in Monroe county 22 months before and 22 months after the initial smoking ban was adopted. In Monroe County, there was a 70 percent decrease in the number of hospital admissions for acute infarction among non-smoking patients with no history of heart disease compared with an 11 percent decrease in Delaware County. This translates into a 59 percent net decrease in the number of non-smoking patient admissions after the Monroe County public smoking ban was enforced.