WASHINGTON (Reuters) — Indoor smoking bans lower the risk of heart attack, even among non-smokers, by reducing exposure to second-hand smoke, a panel of US health experts confirmed in a report on Thursday.

The report, produced by the Institute of Medicine for the US 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.

"Second-hand smoke kills. What this report shows is that smoke-free laws reduce heart attacks in non-smokers," 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 second-hand 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 six 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 second-hand smoke," said John Seffrin, CEO of the American Cancer Society Cancer Action Network.

"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.