Heart attack hospitalizations in the city of Pueblo, Colorado fell sharply after the implementation of a municipal law making workplaces and public places smoke-free, and this decrease was sustained over a three-year period, according to a report in Morbidity and Mortality Weekly Report.
The study found there were 399 hospital admissions for heart attacks in Pueblo in the 18 months before the city’s smoke-free ordinance took effect on July 1, 2003, compared to 237 heart attack hospitalizations in the similar period from 18 months to three years after this date – a decline of 41 percent.
Nine published studies have reported that laws making indoor workplaces and public places smoke-free were associated with sizable, rapid reductions in hospital admissions for heart attacks.
However, most of these studies looked at only a year or less of data after the implementation of smoke-free laws.
This latest study, which covers three years after the Pueblo smoke-free law’s effective date, suggests that the initial reduction in heart attack hospitalizations observed after a smoke-free law takes effect is sustained over an extended period.
Smoke-free laws likely reduce heart attack hospitalizations both by reducing secondhand smoke exposure among nonsmokers and by reducing smoking, with the first factor making the larger contribution.
Researchers also looked at two nearby areas that had not implemented smoke-free ordinances and found no significant decline in heart attack hospitalizations during the same time periods.
"We know that exposure to secondhand smoke has immediate harmful effects on people’s cardiovascular systems, and that prolonged exposure to it can cause heart disease in nonsmoking adults," said Janet Collins, Ph.D., director of CDC’s National Center for Chronic Disease Prevention and Health Promotion. "This study adds to existing evidence that smoke-free policies can dramatically reduce illness and death from heart disease."
Long-term exposure to secondhand smoke is associated with a 25 percent to 30 percent increased risk of heart disease in adult nonsmokers. Secondhand smoke exposure causes an estimated 46,000 heart disease deaths each year among U.S. nonsmokers.
Research shows that breathing secondhand smoke makes blood platelets stick together, in the same way as occurs in a regular smoker.
Even a short time in a smoky room causes platelets to stick together. Secondhand smoke also damages the lining of blood vessels. Together, damage to coronary arteries and clots that block blood flow can cause a heart attack.
Hospital admissions for heart attacks in Pueblo have declined sharply since the ordinance took effect. A previous study reported a 27 percent drop in the rate of heart attack hospitalizations 18 months after the ordinance was enacted compared to 18 months before the smoke-free policy took effect.
The new study found that heart attack hospitalizations continued to fall by an additional 19 percent in the most recent 18-month study period.
The full report is available at www.cdc.gov/mmwr.
For more information about the health effects of secondhand smoke, visit http://www.cdc.gov/tobacco/secondhand_smoke/index.htm.