Indoor smoking bans lower the risk of heart attack, even among nonsmokers, by reducing exposure to secondhand smoke, a panel of U.S. health experts confirmed in a report on Thursday.

The report, produced by the Institute of Medicine for the U.S. Centers for Disease Control and Prevention, provides the most definitive evidence to date that laws that ban smoking from workplaces, restaurants and bars can reduce cardiovascular-related health problems where they are imposed.

Secondhand smoke kills. What this report shows is that smoke-free laws reduce heart attacks in nonsmokers, said CDC director Dr. Thomas Frieden.

But still, most of the country lives in areas that don't have comprehensive smoke-free laws covering all workplaces, all restaurants and all bars, he said.

The CDC asked the independent Institute of Medicine to review research on smoking bans and secondhand smoke after some studies suggested that banning smoking might significantly reduce heart attacks.

The panel of experts reviewed research including 11 studies of smoking bans in the United States, Canada and Europe showing remarkable consistency in the association between bans and reductions in heart attack rates, which in some studies ranged from 6 percent to 47 percent.

There is a causal relationship ... smoking bans decrease the rate of heart attacks, the panel concluded in its report.

Advocacy groups said they hoped the report would encourage passage of more smoking bans, which the CDC estimates covers about 40 percent of the population.

The report confirms beyond a doubt what we have always known -- that smoke-free laws are the most effective way to reduce health problems associated with secondhand smoke, said John Seffrin, CEO of the American Cancer Society Cancer Action Network.

COVERING ALL WORKPLACES

In the United States, 27 states, the District of Columbia and Puerto Rico have enacted smoke-free laws that include restaurants and bars, added Matthew Myers, president of the Campaign for Tobacco-Free Kids. The new report should spur the remaining 23 states to enact comprehensive laws that include all workplaces, restaurants and bars.

The 205-page report said exposure to secondhand smoke could raise the risk of heart disease by 25 to 30 percent.

Secondhand smoke kills an estimated 46,000 Americans from heart disease every year, according to the CDC and the American Heart Association.

The research provided no clear measure of the impact that smoking bans have on health because of variables involving exposure rates for secondhand smoke, ban enforcement, the underlying health of those affected and other factors.

Committee chairwoman Dr. Lynn Goldman of Johns Hopkins University in Baltimore predicted the report would help inform political debate in U.S. states where new bans are under consideration.

This really communicates the benefits for nonsmokers. Nonsmokers are at risk. It's always been an important point. Now we know it's not only in terms of cancer risk but cardiovascular disease risk, she said.

We obviously want to encourage smokers to quit. But we also want to promote public policies which ban smoking that would expose nonsmokers to the risk of heart-attack from second-hand smoke, said Dr. Elizabeth Ross of the American Heart Association, which strongly advocates smoking bans.