"Even breathing in low doses of cigarette smoke can increase one's risk of heart attack," said David Meyers, M.D., M.P.H., professor of Cardiology and Preventive Medicine, University of Kansas School of Medicine and lead investigator of the study, which is the most comprehensive analysis of related studies to date. "Public smoking bans seem to be tremendously effective in reducing heart attack and, theoretically, might also help to prevent lung cancer and emphysema, diseases that develop much more slowly than heart attacks. The cardiac benefits increased with longer ban duration."

According to projections by the authors, a nationwide ban on public smoking could prevent as many as 154,000 heart attacks each year. These findings are particularly important in light of mounting evidence that second-hand smoke exposure is nearly as harmful to the heart as chronic active smoking. Direct smoking doubles the risk of heart attack. Second hand smoke increases the risk by 30 percent.

"Interestingly, public smoking bans had a stronger effect in reducing heart attacks among women and younger individuals, which may be explained, in part, because younger people tend to frequent clubs, restaurants and bars where smoking is a likely part of the social scene," said Dr. Meyers. "Heavily exposed people like those working in the entertainment or hospitality industries are likely to accrue the greatest benefit from smoking bans."

Dr. Meyers adds that smoking remains the leading preventable risk factor for heart attack. Secondhand smoke is thought to increase the likelihood of a heart attack by making the blood "sticky" and more prone to clotting, reducing the amount of "good" (HDL) cholesterol in the body, and putting individuals at greater risk for dangerous heart rhythms, among other factors.

The good news is that the beneficial effects of smoking bans appear to be fairly immediate, with declines in reported heart attack cases within 3 months. The impact of bans was strengthened if compliance was good, if baseline smoking prevalence was low and if air quality was good.

"Several years ago, the idea that secondhand smoke was harmful to the heart was a theory and one with some controversy attached, but this article moves us from the theoretical to fact and to practice. The reduction in heart attacks associated with public smoking bans is a big deal," said Steven Schroeder, M.D., director, Smoking Cessation Leadership Center University of California, San Francisco. "While cardiologists routinely screen for lipid disorders and high blood pressure, they also need to become vigilant about asking patients about tobacco use and secondhand smoke exposure and provide counseling as needed."

Drs. Meyers and Schroeder encourage clinicians to support community smoking bans and other tobacco control measures including tax increases on cigarettes, expanded cessation services including telephone quitlines and educational campaigns. So far, bans on smoking in public places and workplaces have been instituted in 32 states and many cities across the country. As the United States increasingly institutes policies to protect nonsmokers from second hand smoke, authors say these efforts will yield great public health benefits in the form of reduced disease, disability and deaths.

The researchers performed a systematic review and meta-analysis of 10 reports from 11 geographic locations in the United States (MT, CO, NY, IN, OH), Canada and Europe to compare the rates of heart attacks before and after public smoking bans were instituted. Collectively, the studies involved 24 million people and observations of the effect of the bans ranged from two months to three years.

Note: If no author is given, the source is cited instead.

• Smoking
• Heart Disease
• Cholesterol

• Public Health
• Educational Policy
• Political Science

• Ischaemic heart disease
• Coronary heart disease
• Tobacco smoking
• Emphysema
• Lung cancer
• Panic attack