Smog Impedes Kids' Lung Development
California pollution stems growth at most crucial age
WEDNESDAY, Sept. 8, 2004 (HealthDayNews) -- The air in some parts of Southern California air is so dirty that it impedes the development of children's lungs.
By the time they are 18, many children who grow up in polluted areas have lungs that are underdeveloped and that will likely stay that way into adulthood, claims a study in the Sept. 9 issue of the New England Journal of Medicine.
The findings are probably not confined to Southern California. "The pollutants that we studied are likely to be present in any urban environment. They are primarily products of fuel combustion," said study author James Gauderman, an associate professor of preventive medicine at the University of Southern California's Keck School of Medicine.
The years from 10 to 18 are critical ones when it comes to lung development. Girls have fully developed lungs by about the age of 18, while boy's lungs may take a few more years. Thereafter, lung function stays about the same for a short period, then starts declining slowly as the person ages.
This research, called the Children's Health Study, is the longest investigation to date into air pollution and its effect on kids' health.
For eight years between 1993 and 2001, researchers tracked the lung health of 1,759 children aged 10 to 18 and the levels of major pollutants in 12 California communities: Alpine, Atascadero, Lake Elsinore, Lake Arrowhead, Lancaster, Lompoc, Long Beach, Mira Loma, Riverside, San Dimas, Santa Maria and Upland. All were in the southern part of the state but Alpine County, which is in the Sierra Nevada range near San Francisco.
According to the researchers, teenagers living in smoggy areas were nearly five times as likely to have clinically low long function compared to peers living in less polluted areas. Clinically low lung function means that the person has less than 80 percent of the lung function expected for his age.
Short-term effects can include more severe colds that last longer, while long-term effects can include increased risk of death due to cardiovascular and respiratory illness.
"Deficits in lung function are likely to be carried with these kids throughout their life," Gauderman said. ""Kids who start out with lower lung function may be at risk for some of these later-onset diseases earlier in life, or perhaps for a more severe disease course."
"There's not a lot that can be done with reduced lung function that may already exist," Gauderman said. "These findings indicate that if we can improve air quality, that should come with a substantial benefit."
A second study in the same issue of the journal reported more positive findings: Individualized home interventions can drastically cut asthma-related problems in inner-city kids.
"Changing the environment is as important as taking medications," said Dr. Meyer Kattan, a co-author of the study and professor of pediatrics at Mount Sinai School of Medicine in New York City.
While other studies have looked at the effect of reducing exposure to one allergen such as cigarette smoke, few people are allergic to only one thing, Kattan pointed out.
This study was the first time multiple allergens were addressed at one time. In all, 937 children with allergic asthma aged 5 to 11 were enrolled. Half of the group was randomized to receive visits from an environmental counselor who educated the participants on how to reduce exposure based on their particular allergies. "We weren't just focusing on reducing the exposures," Kattan explained. "There was an educational component combined with actually trying to reduce exposure."
The intervention lasted one year, followed by a year of observation. Interventions included such things as mattress and pillow covers, using vacuums with high-efficiency particulate air (HEPA) filters and HEPA air purifiers, and getting professional pest control.
Participants who were visited by an environmental counselor had 19.5 percent fewer days with symptoms, 20.7 percent fewer missed school days each year, and 13.6 percent fewer unscheduled doctor's visits per year. There were also reductions in the levels of allergens in the home, including cockroach and dust-mite allergens. The actual functioning of the participants' airways were not measured.
"The bottom line is that education accompanied by an intervention is the way to do it," said Dr. Albert L. Sheffer, author of an accompanying editorial and director emeritus of the allergy department at Brigham and Women's Hospital in Boston. "This is the first time we've seen statistically significant results."
While the study authors are optimistic that the results can also be achieved in the "real world," others are not so sure.
"This clearly shows that it works. The problem is to motivate people in these socioeconomic situations to take advantage on their own of these observations, and I don't think it's going to be done," Sheffer said, despite the fact that "environmental control is an inexpensive constant chronic approach to asthma care."
For more on childhood asthma, visit the American Academy of Allergy, Asthma and Immunology.