Weight, Adiposity, and Physical Activity as Determinants of an Insulin Sensitivity Index in Pima Indian Children

J. C. Bunt, A. D. Salbe, I. T. Harper, R. L. Hanson, P. A. Tataranni
2003 Diabetes Care  
OBJECTIVE -To determine whether measures of physical activity are related to an insulin sensitivity index ([ISI] 10 4 /fasting insulin ϫ glucose) independent of weight or adiposity in children. RESEARCH DESIGN AND METHODS -We conducted a longitudinal study of 90 Pima Indian children (39 boys and 51 girls) at 5 and 10 years of age measuring adiposity (dual-energy X-ray absorptiometry), physical activity behavior (questionnaire: number of activities per week [ACT], average hours per week [TIME]),
more » ... and energy expenditure (doubly labeled water: physical activity level [PAL]). RESULTS -In cross-sectional analyses, ACT was correlated with ISI at 5 years of age (r ϭ 0.24, P ϭ 0.02) and at 10 years of age (r ϭ 0.21, P ϭ 0.05), but these relationships were not independent of weight or adiposity. PAL was correlated with ISI at 10 years of age (r ϭ 0.39, P ϭ 0.03) but was not independent of weight or adiposity. Longitudinally, ISI decreased from 5 to 10 years of age, and increases in weight and adiposity were associated with decreases in ISI (r ϭ Ϫ0.51 and Ϫ0.41, respectively; both P Ͻ 0.0001). ACT decreased from 5 to 10 years of age, but children who had smaller decreases in ACT had smaller decreases in ISI, independent of increases in weight or adiposity (partial r ϭ 0.22, P ϭ 0.04 adjusted for either weight or adiposity). CONCLUSIONS -These data suggest that early establishment and maintenance of an active lifestyle can have a beneficial effect on ISI that is partially independent of changes in weight or adiposity. This is particularly relevant considering the current epidemics of both obesity and type 2 diabetes in children. Abbreviations: ACT, activities per week; AEE, activity energy expenditure; DLW, doubly labeled water; GLM, general linear model; ISI, insulin sensitivity index; PAL, physical activity level; RMR, resting metabolic rate; TEE, total energy expenditure; TIME, average hours per week. A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.
doi:10.2337/diacare.26.9.2524 pmid:12941713 fatcat:par2k4lvozcoracx3ft3ecgw7m