1. ¹Division of Nutrition and Physical Activity, Centers for Disease Control and Prevention K-26, Atlanta, GA 30341-3717, USA
2. ²Tulane Center for Cardiovascular Health, Tulane University School of Public Health and Tropical Medicine, 1440 Canal St Suite 2140, New Orleans, LA 70112, USA

Correspondence: DS Freedman, CDC Mailstop K-26, 4770 Buford Hwy, Atlanta, GA 30341-3717, USA. E-mail: DFreedman@CDC.gov

Received 16 April 2003; Revised 21 August 2003; Accepted 29 September 2003; Published online 2 December 2003.

Abstract

OBJECTIVE: Although the body mass index (BMI, mass index, kg/m²) is widely used as a surrogate measure of adiposity, it is moderately associated (r0.3) 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 95th 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.