Clinical and genetic correlates of exercise performance in young children with cystic fibrosis.

Exercise performance in individuals with cystic fibrosis has been shown to be related to the extent of pulmonary dysfunction and undernutrition and genetic profile. The aim of this study was to examine these relationships in young children with cystic fibrosis. The participants were 64 children ages 8 to 11 years (M = 9.3, SD = 0.9) with cystic fibrosis and pancreatic insufficiency recruited from 13 different U.S. cystic fibrosis centers. Assigned to one of three groups by deltaF508 status: deltaF508/deltaF508 homozygous, deltaF508/Other heterozygous, and Other/Other, growth, nutritional and pulmonary status, and exercise performance were measured. Differences in exercise performance, pulmonary function, and nutritional status were not observed among the three groups. However, undernutrition and decreased pulmonary function were associated with measures of exercise performance. These results imply no effect of deltaF508 status on overall functional capacity during preadolescence in children with cystic fibrosis. Rather, the extent of pulmonary disease and undernutrition were associated with functional performance.