Evaluating the utility of the body adiposity index in adolescent boys and girls.

OBJECTIVES: This study examines the ability of the body adiposity index to estimate percent body fat in a mixed sample of adolescents. Additionally, the sensitivity of the body adiposity index to identify adolescents with increased health risk (i.e., high waist circumference) was determined and compared to other anthropometric indicators of health (skinfolds and body mass index).
DESIGN: Cross-sectional.
METHODS: Anthropometric data (height, weight, waist circumference, and skinfolds) were collected on 913 adolescents (50% boys; mean age: 15.1yrs). Percent body fat estimates were determined using skinfold equations and the body adiposity index, while body mass index was calculated using weight and height (wt/ht(2)). Age- and gender-specific thresholds for waist circumference, body fat, and body mass index were utilized to create categorical values. Correlation coefficients, t-tests, and kappa statistics were used to describe the relationship between anthropometric variables.
RESULTS: Correlation coefficients revealed an association between percent body fat estimates from skinfolds and body adiposity index (boys 0.77; girls 0.67); however, the body adiposity index systematically overestimated percent body fat at lower levels of adiposity, primarily in boys. Higher mean percent body fat estimates were reported using the body adiposity index compared to skinfolds in boys (25.1% vs. 17.8%), while the opposite relationship was found in girls (body adiposity index 28.5% vs. skinfolds 29.6%). Among boys and girls, correlations to waist circumference and also sensitivity values were higher for body mass index compared to either skinfolds or body adiposity index.
CONCLUSIONS: No clear advantage exists in using the body adiposity index to estimate percent body fat or to identify adolescents with increased health risk. The results support the continued use of the body mass index to identify adolescents with increased health risk.