New research shows that smoking bans spare many children with asthma from being hospitalized, a finding that suggests smoke-free laws have even greater health benefits than previously believed.

Other studies have charted the decline in adult heart attack rates after smoking bans were adopted. The new study, conducted in Scotland, looked at asthma-related hospitalizations of kids, which fell 13 percent a year after smoking was barred in 2006 from workplaces and public buildings, including bars and restaurants.

Before the ban, admissions had been rising 5 percent a year in Scotland, which has a notoriously poor health record among European countries.

Earlier U.S. studies, in Arizona and Kentucky, reached similar conclusions. But this was the largest study of its kind — and offered the strongest case that smoking bans can bring immediate health improvements for many people.

"The effects of smoke-free laws are way bigger than you would expect," said Stanton Glantz, a University of California-San Francisco researcher who specializes in the health effects of smoking. He was not involved in the new study, published in Thursday's New England Journal of Medicine.

Cigarette smoke is a trigger for asthma attacks. So researchers reasoned that tracking severe cases was perhaps the best way to measure a smoking ban's immediate effect on children.
"Acute asthma is the tip of the iceberg," more easily tracked than less severe breathing problems, ear infections and other problems seen in children that have been linked to a caregiver's smoking, said Terry Pechacek of the Centers for Disease Control and Prevention's office on smoking and health.

About 40 percent of American children who go to hospitals because of asthma attacks live with smokers — a high proportion, given that only about 21 percent of U.S. adults smoke, according to CDC statistics.

Smoking bans have become increasingly common in the United States, where 35 states and the District of Columbia have laws that bar smoking in workplaces or restaurants and bars, or both. And more than 3,100 cities and towns have their own restrictions, according to the American Nonsmokers' Rights Foundation.

The push continues: This week, New York City Mayor Michael Bloomberg announced city officials will pursue a broad extension of the city's smoking ban to parks, beaches and pedestrian plazas throughout the city.

Many European countries — including Britain, France and Germany — forbid smoking in all public places. But Italy, Greece and some others have been slower to adopt the bans, sometimes simply limiting smoking in certain areas.

In the new report, researchers looked at emergency hospital admissions for asthma at all of Scotland's hospitals from January 2000 through October 2009. The data was for kids age 14 and younger.

They found that hospital admissions for children's asthma attacks were increasing by 5 percent per year before the ban, reaching about six admissions per day on average in January 2006. But afterward, children's asthma attacks declined by 13 percent a year, falling to below five admissions per day in October 2009.

The ban largely targets places where adults work and socialize. But there seems to be a ripple effect: It made smoking less popular and led significant numbers of adult smokers to cut back or quit their habit at home, where the kids were, said Dr. Jill Pell, a study author.

"People are choosing to protect their kids even when they don't have to," said Pell, a University of Glasgow professor of public health.

That's consistent with U.S. research, which has shown that smoking bans were followed by a decline in smoking at home, Pechacek said.