Asthma exacerbations and urinary 1-hydroxypyrene in U.S. children age 6-11 years, NHANES 1999-2004

Introduction: Wheezing in children has been associated with ambient exposures to polycyclic aromatic hydrocarbons (PAHs), chemical byproducts of incomplete combustion that are ubiquitous in the environment; and elevated urinary PAH metabolite levels have been reported in children experiencing asthma exacerbations; however, studies have not quantified the risk for asthma exacerbations associated with biomarkers of PAH exposure in children. The objective of this study was to investigate the association between 1-hydroxypyrene (1-OHP), a urinary metabolite of the parent PAH compound pyrene, and wheezing-related exacerbations in school-age asthmatic children.

Methods: Data were obtained from the National Health Examination and Nutrition Survey (NHANES), 1999-2004. Asthma exacerbation was defined as having sought medical attention for wheezing, or school absences due to wheezing, during the past year. Multiple logistic regression analysis was conducted to measure the statistical association between 1-OHP and emergency department (ED) or physician (MD) office visits for wheezing; and between1-OHP and school absences due to wheezing; among children ever diagnosed with asthma (n=125), adjusted for urinary creatinine, gender, minority, poverty and overweight status. Children with serum cotinine levels >10 ng/L were excluded.

Findings: The incremental log 10 increase of urinary 1-OHP (ng/L) was significantly associated with 3.83 greater odds for ED or MD visit for wheezing (OR=3.83; p=0.01; 95% CI=1.33, 11.05) and 5.06 greater odds for school absence due to wheezing (OR=5.06; p=0.01; 95% CI=1.48, 17.36).

Conclusion: Findings suggest that PAH exposure is associated with increased risk of asthma exacerbations among children age 6-11 years in the U.S.