Three years after Pueblo, Colo., passed a law banning smoking in private workplaces and public places, heart attacks among city residents fell by an impressive 41%.
The study in today's Morbidity and Mortality Weekly Report, published by the national Centers for Disease Control and Prevention, is the 10th to associate no-smoking laws with reductions in heart attack rates. But unlike previous studies, it examined the health effects of the ordinance beyond the first year of implementation.
Not only were the health improvements sustained, heart attack rates dropped even more after three years than after one.
In the 18 months before July 1, 2003, when the smoke-free ordinance went into effect, Pueblo residents suffered heart attacks at the rate of 257 per 100,000 person-years. Eighteen months later, the rate had dropped to 187, and by June 30, 2006, to 152 heart attacks per 100,000 person-years.
The study compared Pueblo's heart attack rates with two similar areas that did not have smoking bans. Over the same time period, the two control groups showed no significant changes in heart attack rates.
Smoke-free ordinances are designed primarily to protect nonsmokers from second-hand smoke; animal and human studies have shown that even relatively small doses of tobacco smoke can increase the risk of heart disease. But because the study did not look at whether heart-attack victims were smokers or nonsmokers, it's impossible to say how much of the decline can be attributed to a drop in second-hand smoke exposure among nonsmokers and how much to a drop in smoking among smokers.
Either way, Pueblo's smoking ban can take the credit: In addition to reducing second-hand smoke, such laws have been shown to prompt smoking bans in private homes and to encourage some smokers to quit.