Sept. 8, 2004 -- Children who live in areas with the poorest air quality are five times as likely to have lung development problems as those breathing cleaner air, according to findings from the largest and longest study ever published on the effect of air pollution on the health of kids and adolescents.
The study, funded in part by the National Institute of Environmental Health Sciences, followed 1,759 children living in 12 Southern California communities from age 10 to age 18. The areas included Los Angeles, which has some of the highest air pollution levels in the country, and less polluted communities outside the Los Angeles area.
Lung function was tested annually, and researchers reported that children living in communities with the most air pollution were far more likely to have "low forced expiratory volume" - a test that provides information on the forcefulness of a person's breathing. Abnormal results indicate changes in the function of the lung or lung disease.
The findings are reported in the Sept. 9 issue of The New England Journal of Medicine.
"Our study shows significant deficits in lung development associated with pollution exposure among kids in their late teens," says lead researcher Jim Gauderman, PhD, of the University of Southern California Keck School of Medicine. "We don't expect that these deficits will be made up because lung development is essentially done by this age. These deficits are likely to be carried into adult life and could translate into an increased risk for disease and death."
Similar to Secondhand Smoke
Studies have long linked air pollution to compromised lung function in adults, and more recent research suggests that living in a community with poor air quality increases the risk of heart attack and death from heart disease.
But it has not been clear if air pollution actually interferes with lung development in children. Lungs typically grow to full capacity during the teen years, and then lung function gradually declines throughout adulthood by about 1% per year after age 20.
Gauderman and colleagues first reported the link between childhood exposure to polluted air and diminished lung development four years ago. Now they report that the negative effects of pollution exposure follow children into adulthood.
A linear link was seen between exposure to air pollution and lung development in the eight-year follow-up study, with kids exposed to the most pollution being most likely to have deficits in lung function compared with other children exposed to less air pollutants. Pollutants were found to be associated with diminished lung development.
"The deficits we saw (in children living in polluted communities) were similar to that seen among kids exposed to secondhand smoke," Gauderman tells WebMD.
Study co-author John Peters, MD, called the potential long-term effects of reduced lung function throughout life "alarming."
The researchers will continue to follow the study participants into their 20s, in part to determine if those who move to less polluted areas experience improvements in lung function.
In an editorial accompanying the study, environmental epidemiologist C. Arden Pope III, PhD, noted that the findings could be considered good news because they prove that controlling air pollution "represents an important opportunity to prevent disease."
He wrote that while improvements in air quality have been made in the U.S., pollution is still a major problem in many areas of the world.
"The good news is that here in the U.S. we have made some real progress, and the literature suggests that continued improvements in air quality can result in continued improvements in cardiopulmonary health," Pope tells WebMD. "The bad news, of course, is that we still aren't where we want to be. And now it is clear that pollution-related health effects can occur even with low to moderate exposures."