The number of premature births and children’s hospital visits for asthma dropped significantly in parts of the United States, Canada, and Europe barely a year after they enacted smoking bans, researchers reported in The Lancet last week.
The new analysis combined the results of 11 studies encompassing more than 2.5 million births and nearly 250,000 asthma attacks. Experts called it the best evidence to date that legislation creating smoke-free public places and workplaces improves children’s health, even in the womb. The results are “very impressive,” said Dr. Brian Mercer, chairman of obstetrics and gynecology at MetroHealth Medical Center in Cleveland, who noted that half a million American babies are born prematurely each year.
“If you could prevent 10 percent, you’d prevent nearly 50,000 premature babies in the U.S. alone each year,” said Dr. Mercer, who was not involved in the study.
Dr. Vincenzo Berghella, the president of the Society for Maternal-Fetal Medicine, said: “There are over a million babies dying of being born preterm every year in the world. We can make major strides in decreasing that with smoking bans.”
After an exhaustive review of relevant studies spanning 38 years, the researchers analyzed five that looked at perinatal and child health after local smoking bans in North America and six studies conducted after national bans in Europe. Hospital visits for childhood asthma and premature births both declined about 10 percent in the year after smoking bans took effect, the researchers found.
The investigators also pooled data from two studies and found a 5 percent reduction in the number of children born very small for their gestational age after the introduction of smoke-free laws.
An earlier analysis of the impact of smoking bans on adult health demonstrated a 15 percent reduction in cardiovascular events. The new report offers “another very good reason to institute smoking bans in public places,” said Dr. Muktar Aliyu, an associate professor of health policy and medicine at Vanderbilt University who has studied birth outcomes linked to maternal smoking. Only 16 percent of the world’s population is covered by comprehensive smoke-free laws, and 40 percent of children worldwide are routinely exposed to secondhand smoke.
Growing up, Dr. Aliyu said, he stifled coughs as his father smoked in the car. “Adults can just walk away or change their environment,” he said. “A child can’t.”
Despite fears that bans could lead to more smoking at home, studies have shown the opposite is true.
“Strong smoke-free laws change social norms about smoking, and consequently people implement smoke-free policies in their own homes as well,” said Joanna Cohen, the director of the Institute for Global Tobacco Control at the Johns Hopkins University School of Public Health. That’s probably how “smoke-free policies have such a direct impact on child health,” she added.
A 2006 surgeon general’s report declared that any amount of secondhand smoke was dangerous. Yet “we are still not doing a good enough job at protecting our children from secondhand smoke,” Dr. Cohen said. About half of Americans are protected by complete smoke-free policies in workplaces, restaurants and bars, according to the Americans Nonsmokers’ Rights Foundation, a nonprofit group. In a commentary accompanying the new report, its authors argue that strong tobacco control policies are a way to contain medical costs now, not in a decade or two, as experts used to think.
Medical expenses for asthma exceeded $50 billion nationwide in 2007. So even a 10 percent decrease in emergency-room visits for asthma could translate into roughly a $5 billion savings, said Dr. Sara Kalkhoran, an internist at the University of California, San Francisco, and a co-author of the commentary.
The new analysis did not prove that smoke-free laws caused the improvements in children’s health. And the researchers didn’t evaluate other factors, like taxation of tobacco products and advertisement bans, which could have contributed, said Dr. Catherine Y. Spong, the director of extramural research at National Institute of Child Health and Human Development.
“We can’t say that every country that does this, that it will help to this degree,” she said, referring to smoking bans in public places. But this “very well-done analysis” again demonstrated “the importance of limiting exposure to smoke for pregnant women and children,” she said.
The authors note that further studies are needed to estimate the effect of smoke-free laws on respiratory tract infections in children, a major problem of secondhand smoke. The authors also cite a “pressing need” for studies of tobacco control laws in low- to middle-income countries.
“Our hope is that this kind of work will catalyze the introduction of smoke-free laws, and as that is done, the opportunity is taken to evaluate their impact and strengthen the evidence,” said Dr. Aziz Sheikh, the senior author of the paper and a health care policy fellow at Brigham and Women’s Hospital in Boston.
Still, Dr. Sheikh and his co-authors concluded, “It is now evident that early-life protection from involuntary secondhand smoke exposure holds great potential to reduce the consequential disease burden.”