Influences of asthma and household environment on lung function in children and adolescents: the third national health and nutrition examination survey.

The authors examined influences of asthma and household environment (passive smoking, use of a gas stove, and having a dog or cat) on five measures of spirometric lung function among 8- to 16-year-old subjects, as measured cross-sectionally in the Third National Health and Nutrition Examination Survey (NHANES III) (1988-1994). In regression models, independent variables included asthma status, household environmental factors, age, and anthropometric measurements. Regression analyses were weighted by the NHANES III examination sample weighting factor, and results were adjusted for clustering in the sampling design. There were distinct sex differences in the results. In girls, lung function was lowest among active asthmatics taking prescription respiratory medicine, whereas lung function in other active and inactive asthmatics did not differ greatly from that in nonasthmatics. In boys, however, all groups of asthmatics had substantially lower lung function than nonasthmatics. Differences in lung function between active asthmatics and nonasthmatics were stable with increasing age. However, the lung function of inactive asthmatic girls and boys returned to and diverged from nonasthmatics' levels, respectively. In asthmatic girls, passive smoking was associated with reduced lung function; having a dog or cat was associated with increased lung function; and gas stove use was associated with reduced lung function among subjects not taking prescription respiratory medicine.