Effects of ambient air pollution on symptom severity and medication use in children with asthma.
BACKGROUND
Exposure to air pollutants has been investigated as a possible cause of asthma attacks in children.


OBJECTIVE
To investigate the short-term effects of air pollutants on a panel of 133 children with asthma who enrolled in the Childhood Asthma Management Program.


METHODS
During screening, the children completed daily diary cards for an average of 58 days to indicate their medication use and asthma severity. We used ordinal logistic regression to compare the odds of a more serious relative to a less serious asthma attack, and we used a Poisson model to analyze medication use. In both analyses we accommodate dependence in the data and different periods of observation for study subjects.


RESULTS
Our results indicate that a 10-microg/m3 increase in particulate matter less than or equal to 2.5 microm (PM2.5) lagged 1 day was associated with a 1.20 times increased odds of having a more serious asthma attack [95% confidence interval (CI), 1.05 to 1.37] and a 1.08-fold increase in medication use (95% CI, 1.01 to 1.15). A 10-microg/m3 increase in particulate matter less than or equal to 10 microm (PM10) increased the odds of a more serious asthma attack (odds ratio = 1.12; 95% CI, 1.04 to 1.22) and also increased medication use (relative risk = 1.05; 95% CI, 1.00 to 1.09).


CONCLUSIONS
Increases in PM2.5 and PM10 are significantly associated with an increased risk of more severe asthma attacks and medication use in Seattle area children with asthma. We also found associations with carbon monoxide, but we believe that carbon monoxide is a marker for exposure to combustion byproducts.
Department of Biostatistics, University of Washington, Seattle, Washington 98195-7232, USA.
James C
JC
Slaughter
Thomas
T
Lumley
Lianne
L
Sheppard
Jane Q
JQ
Koenig
Gail G
GG
Shapiro
D000293:Adolescent; D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution; D000420:Albuterol / Q000627:therapeutic use*; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology; D001993:Bronchodilator Agents / Q000627:therapeutic use*; D002248:Carbon Monoxide / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D009391:Nephelometry and Turbidimetry; D010316:Particle Size; D012720:Severity of Illness Index
D000393:Air Pollutants; D001993:Bronchodilator Agents; D002248:Carbon Monoxide; D000420:Albuterol