Scotland's 2006 ban on smoking in public places cut the heart attack rate by 17 percent within one year, with non-smokers benefiting most, researchers reported on Wednesday.
The study is the first real-time, large-scale look at how a ban on second-hand smoke might benefit smokers and nonsmokers. Earlier research looked at the effect of smoking bans in individual cities, or had other limitations.
"A total of 67 percent of the decrease involved non-smokers," Dr. Jill Pell of the University of Glasgow and colleagues wrote in the New England Journal of Medicine.
The number of people admitted to nine Scottish hospitals for a heart attack dropped 14 percent among smokers, 19 percent among former smokers and 21 percent for those who had never smoked.
In contrast, the rate declined only by 4 percent in England during that period, before a ban went into effect there. Historically, heart attack rates in Scotland had been dropping 3 percent per year.
"There are a number of countries considering whether to impose similar bans, and obviously the more evidence of the effectiveness of such intervention, the more likely they are to do that," Pell said in a telephone interview.
Among the 5,919 cases she and her colleagues studied, women seemed to benefit the most. The heart attack rate among smokers dropped 19 percent compared to an 11 percent decline among men. It dropped 23 percent among female nonsmokers versus 18 percent among nonsmoking males.
There had been concern at the start of the ban that it would increase the amount of smoking in private homes.
Using measurements of a chemical that gauges exposure to cigarette smoke, the researchers found that the fear was unfounded, and exposure to secondhand smoke declined by 42 percent.
"So it seems that the ban is not only protecting non-smokers, it is changing society's idea of what is normal," said Pell.
When New York imposed tough restrictions on public smoking, exposure levels declined by 47 percent.
The United States does not have national smoking restrictions. Limits are placed by individual states or municipalities.
