Inter-relationships among childhood BMI, childhood height, and adult obesity: the Bogalusa Heart Study

OBJECTIVE: Although the body mass index (BMI, mass index, kg/m(2)) is widely used as a surrogate measure of adiposity, it is moderately associated ( rsimilar to0.3) with height among children. We examined whether the resulting preferential classification of taller children as overweight is appropriate. DESIGN: Cross-sectional analyses of children ( ages, 3 - 17 y) examined the relation of height to adiposity ( as assessed by BMI and skinfold thicknesses) and fasting levels of insulin. Longitudinal analyses examined the relation of childhood height and weight height indices to adult ( mean age, 25 y) levels of adiposity and fasting insulin. SUBJECTS: Children ( n = 11 406) and adults ( n = 2911) who had participated in the Bogalusa Heart Study. MEASUREMENTS: We constructed three weight - height indices: BMI, W/H-3, and W/H-p. The triceps and subscapular skinfolds, as well as fasting levels of insulin, were also measured. RESULTS: The classification of children as overweight (BMI-for- age greater than or equal to95th percentile) varied markedly by height, with a 10-fold difference in the prevalence of overweight across quintiles of height between the ages of 3 and 10 y. Childhood height, however, was also related to skinfold thicknesses and insulin levels, and all associations were modified in a similar manner by age. Furthermore, childhood height was related to adult adiposity, and of the three childhood weight - height indices, BMI showed the strongest associations with adult adiposity. CONCLUSIONS: Because BMI reflects the positive association between height and adiposity among children, it is a better weight - height index than is either W/H-3 or W/H-p.