Abstracts: ISEE 20th Annual Conference, Pasadena, California, October 12–16, 2008: Contributed Abstracts
Ethnic Difference in the Effect of Asthma on Pulmonary Function in Children
Asthma is the most common chronic disease in children. The impact of asthma on both acute and chronic lung function deficits is well known, but there has been little study of how these effects of asthma vary by race or ethnicity. One possible reason for paucity of research on this topic is the limited statistical power of previous studies to detect gender- and race/ethnic- specific differences.
We evaluated ethnic differences in the effect of asthma on lung function among 3245 (1099 Hispanic and 2146 non-Hispanic White) school children with at least two spirometric tests during 8 years of follow-up in the Children's Health Study. The large sample size and yearly assessment of asthma and lung function in the population-based sample were major strengths of the study. Gender-specific mixed-effects regression spline models were fitted separately for each ethnic group and for both groups combined.
In boys, asthma was associated with greater deficits in lung volume (FVC) in Hispanic (−1.30%) than in Non-Hispanic Whites (0.63%, interaction P-value 0.047). In girls, Hispanics with asthma had greater deficits in flow rates than Non-Hispanic Whites. For example, the asthma-associated deficit in MMEF was −5.13% among Hispanic girls and −0.58% among non-Hispanic white girls (interaction P-value 0.009). A bigger impact of asthma in Hispanic girls was also found for FEV1, FEF75 and PEFR (interaction P-value 0.04, 0.07, and 0.005, respectively). The impact of ethnicity on lung function also varied by age at asthma diagnosis. FVC deficits occurred largely in Hispanic boys diagnosed under age 5, while larger deficits in flow rates occurred among Hispanic girls with later onset, compared to non-Hispanic Whites.
We conclude that the impact of asthma on lung function was larger in Hispanic than Non-Hispanic White children, and that these effects varied by gender and age of diagnosis. Further study is warranted to understand the reasons for these differences.© 2008 Lippincott Williams & Wilkins, Inc.