Data from physician diagnosed pediatric asthma were assessed for relationships with the potential risk factors body mass index, percent fat and lean tissue, obesity, and physical activity. The data pertained to a large population-based multi-ethnic cohort of school children (n=826) from the Detroit area for whom, using dual-energy x-ray absorptiometry, precise measurements of whole body bone mass, and soft tissue composition were collected along with height and weight measurements in 1992-1993, when the children were nine years old. Detailed data on physical activity, collected with consultation with an exercise physiologist, and prevalent asthma diagnosis and symptoms, collected under the direction of a respiratory disease/pediatric epidemiologist and a pediatric allergist, were obtained at the same time.