Scottish kids’ asthma declined after smoking ban

Scottish children are breathing more than a wee bit easier since a law banning smoking in public buildings went into effect in 2006. Hospitals now report treating fewer kids for emergency asthma attacks, an improvement that researchers suspect stems from decreased exposure to secondhand smoke, which can exacerbate asthma.

The ban prohibits smoking in most enclosed public places, including pubs, restaurants, office buildings, libraries and shops. “If it’s got three walls and a roof, it’s probably included,” says study coauthor Jill Pell, an epidemiologist and public health physician at Scotland’s University of Glasgow. 

But children don’t spend much time in restaurants and bars. In Scotland, the smoking ban may be benefiting them indirectly by curbing smoking in the home, Pell says.

There was concern in Scotland that the ban might do the opposite by pushing smoking out of pubs and into homes, placing children at greater risk of breathing secondhand smoke. But a 2007 study of saliva samples from grade school children found that  levels of the nicotine metabolite cotinine decreased from 2006 to 2007. Meanwhile, phone calls to smoking help lines rose at the time of the ban. Although the number of people who smoke hasn’t dropped, surveys indicate that people are smoking fewer cigarettes per day, Pell says.

All this may be translating into less smoking in the home, not more, as smokers scale back their habit, Pell says. Also, nonsmoking spouses now have leverage to ask smokers to take it outside, she says. “They can say, ‘You’re protecting people we don’t even know in public buildings. You should be protecting our children, too.’”

The new asthma data bolster her surmise. Pell and her colleagues scanned hospital records of more than 21,000 children under age 15 who were treated for asthma from January 2000 to October 2009. Such cases had been rising by 4.4 percent annually from 2000 to 2006. But over the three years after the ban, the average annual number of cases dropped by nearly 20 percent compared with the annual average measured before the ban, the researchers report in the Sept. 16 New England Journal of Medicine. The researchers accounted for differences in sex, age, urban versus rural living and socioeconomic status in making the comparison.

Many studies of children have linked secondhand smoke exposure to asthma risk in children. In 2007, researchers at the California Environmental Protection Agency in Oakland analyzed 38 studies that accounted for allergies in children and found a clear association between exposure to secondhand smoke and increased risk of asthma.

Young children are at particularly high risk because they breathe faster and have smaller airways, Pell says.

Earlier this year, Canadian researchers assessing admissions to hospitals for cardiovascular or respiratory problems in people of all ages found that these declined by at least one-third in Toronto since that city banned smoking in restaurants in 2001.

That finding might even understate the effect that the ban has had on respiratory problems, says study coauthor Alisa Naiman, a primary care physician at the University of Toronto. The researchers counted only patients who were admitted to hospitals and not those who were treated and released, she says.

Toronto has since expanded its smoking ban to include bars, bus stops and even inside cars carrying minors. “It’s really become part of the lifestyle here,” Naiman says. She argues that the Scottish study and similar research foster acceptance of smoking bans.  “The scientific evidence makes people willing to accept increasingly legislated changes in their lives,” she says.