Los Angeles, Nov. 15, 2006- Children and teens who smoke cigarettes have nearly four times the risk of developing asthma in their teens compared to children and teens who do not smoke, researchers at the University of Southern California (USC) report.
Lead researcher Frank Gilliland, M.D., Ph.D., professor of preventive medicine at the Keck School of Medicine of USC, also found that children who were exposed to cigarette smoke in their mothers' wombs have even higher risks of developing asthma, almost nine times the risk of those who didn't smoke. Their results appear Nov. 15 in the American Journal of Respiratory and Critical Care Medicine.
"We've been studying this group of children long enough that now some of them have started smoking," Gilliland says. "We found that teens who started smoking have a four times higher risk of developing asthma compared to teens who don't smoke. But if those same teenagers were also exposed to tobacco smoke before they were born, they get more than a double whammy - nine times the risk of getting asthma."
While cigarette smoke is known to have negative effects on lungs, including inflammation and hyper-responsive airways, evidence linking smoking and the development of asthma has been mixed. Some of that difficulty lies in trying to separate out confounding variables in adult smokers over their lifetimes, Gilliland and his co-researchers say. By studying adolescents, who had a shorter history of smoking, the researchers were able to make a clearer connection.
"These findings suggest that the harmful effects of cigarette smoking are not limited to those who are long-term heavy smokers," says National Institute of Environmental Health Sciences Director David A. Schwartz, M.D. "The study results provide clear evidence of a link between short-term smoking and respiratory illness in adolescents and young adults."