Ethnic differences in the effect of asthma on pulmonary function in children.

RATIONALE: The impact of asthma on chronic lung function deficits is well known. However, there has been little study of ethnic differences in these asthma-associated deficits.

OBJECTIVES: To examine whether there are ethnic differences in the effects of asthma on children's lung function.

METHODS: We evaluated the impact of asthma on lung function in 3,245 Hispanic and non-Hispanic white school children (age 10-18 yr) in a longitudinal analysis of the Southern California Children's Health Study. Sex-specific mixed-effects regression spline models were fitted separately for each ethnic group.

MEASUREMENTS AND MAIN RESULTS: Large deficits in flows were observed among children with asthma diagnosed before age 4 years regardless of ethnicity. Hispanic girls with asthma had greater deficits in flows than non-Hispanic girls and were largest for maximal midexpiratory flow (-5.13% compared with -0.58%, respectively). A bigger impact of asthma in Hispanic girls was also found for FEV(1), FEF(75), and PEF (P value 0.04, 0.07, and 0.005, respectively). These ethnic differences were limited to girls diagnosed after age 4 years. In boys, asthma was also associated with greater deficits in flows among Hispanic than in non-Hispanic white children (differences that were not statistically significant). Ethnic differences in prevalence of pets and pests in the home, health insurance coverage, parental education, and smoking did not explain the pattern of lung function differences.

CONCLUSIONS: Larger asthma-associated lung function deficits in Hispanics, especially among girls, merit further investigation to determine public health implications and to identify causes amenable to intervention.