ditional evidence that secondhand smoke kills and smoke-free workplace laws save lives. The study was presented last month to the American Heart Association's Scientific Sessions, in Orlando, Fla.

Its research shows that the incidence of heart attacks and sudden cardiac deaths was cut in half among Olmsted County, Minn., residents after a smoke-free ordinance took effect. Adult smoking dropped 23 percent during the same time frame, as the rates of other risk factors such as high blood pressure, high cholesterol, diabetes, and obesity remained stable or increased.

"This study adds to the observation that smoke-free workplace laws help reduce the chances of having a heart attack, but for the first time, we report these laws also reduce the chances of sudden cardiac death," says Dr. Richard Hurt, director of Mayo Clinic's Nicotine Dependence Center. "The study shows that everyone, especially people with known coronary artery disease, should avoid contact with secondhand smoke. They should have no—literally no—exposure to second-hand smoke because it is too dangerous to their health."

The Mayo Clinic asserts that Hurt played an instrumental role in the passage of smoke-free ordinances in Olmsted County and the state of Minnesota.

Hurt says evidence from this new study will strengthen efforts by the Global Smoke-Free Worksite Challenge, a recently formed tobacco control advocacy collaboration that debuted at a Clinton Global Initiative event. The Challenge will encourage other countries and employers to expand the number of employees able to work in smoke-free environments.

"We are going to use this information to help us convince corporations—convince countries—that this is the right thing to do to protect the health of their workers and their citizens," Hurt says.

The study draws data from the Rochester Epidemiology Project, a long-term, collaborative medical records project among health care providers in Olmsted County. The project makes Mayo Clinic one of the few places in the world where retrospective population-based studies are possible and allows researchers at Mayo Clinic to zero in on the frequency of certain conditions.

"This study underscores once more the importance of monitoring heart disease in communities in order to understand how to enhance cardiovascular health," says Dr. Veronique Roger, director of Mayo Clinic's Center for the Science of Health Care Delivery. Roger leads cardiovascular disease surveillance through the Rochester Epidemiology Project.

The population-based study showed that during the 18 months before Olmsted County's first smoke-free law for restaurants was passed in 2002, the regional incidence of heart attack was 212.3 cases per 100,000 residents. In the 18 months following a comprehensive smoke-free ordinance in 2007, in which restaurants and workplaces became smoke-free, that rate dropped to 102.9 per 100,000 residents, a decrease of about 45 percent. Additionally, during these two time periods, the incidence of sudden cardiac death fell from 152.5 to 76.6 per 100,000 residents-a 50 percent reduction.

"Our findings provide support to the life-saving effect that smoke-free legislation can have among community members affected by these laws," says co-author Dr. Jon Ebbert, associate director of Mayo Clinic's Nicotine Dependence Center.

Other Mayo study authors are Dr. Ivana Croghan, Darrell Schroeder, Susan Weston, and Sheila M. McNallan.

The study was supported by a grant from ClearWay Minnesota, an independent, nonprofit organization that seeks to improve the health of all Minnesotans by reducing tobacco use and exposure to secondhand smoke through research, action, and collaboration.

Global Smoke-Free Worksite Challenge is a collaboration among the American Cancer Society, the Global Business Coalition on Health, Johnson & Johnson, Mayo Clinic, the Campaign for Tobacco-Free Kids, and the U.S. Department of Health & Human Services.