By Liz Szabo, USA TODAY

Community smoking bans have an immediate and dramatic effect on reducing heart attacks, according to two new analyses of laws in the USA, Canada and Europe.

Two separate analyses released Monday each found that heart attack rates fall 17% within a year after smoking bans take effect. One analysis, which included 13 studies, appears in Circulation: Journal of the American Heart Association. A second analysis, which considered 11 studies, appears in the Journal of the American College of Cardiology.

Cigarette smoke can trigger a heart attack in people with underlying heart disease by causing clots or spasms in the blood vessels, says David Goff, a spokesman for the American Heart Association who wasn’t involved in either study.

Given that there are about 920,000 heart attacks every year, the studies suggests that public smoking bans could prevent more than 150,000 of these, according to the Cardiology paper.

Taken together, the findings provide strong, consistent evidence that the country should enact more smoke-free laws, Goff says.

“This is a huge, huge effect for a very, very low cost,” says Stanton Glantz of the University of California-San Francisco, co-author of the Circulation study.

Smoke-free laws reduce heart attacks in three ways, Glantz says. First, they protect smokers themselves. Second, they protect non-smokers — especially waiters and bartenders — from secondhand smoke. Third, they encourage people to quit or smoke less by making it more difficult for people to find place to light up.

Smoke-free laws have other healthy side effects, says Tom Glynn of the American Cancer Society. They also reduce the risk of lung cancer, although more slowly.

Preventing heart attacks can save money.

Cardiovascular disease costs the country $475.3 billion a year, both in direct costs, such as hospital stays, and indirect costs, such as missed work, Goff says. It costs at least $14,000 to treat one heart attack patient in the hospital, says Goff, who says that cardiac rehab, medication and other care cost even more.

“Really pushing strong smoke-free policies has a huge effect on health care costs by simply avoiding disease,” Glantz says.

Thirty-one states now forbid smoking in workplaces, restaurants or bars, according to the American Nonsmokers’ Rights Foundation. About one in five adults smoke, according to the Centers for Disease Control and Prevention.