Comparison of body fatness measurements by BMI and skinfolds vs dual energy X-ray absorptiometry and their relation to cardiovascular risk factors in adolescents

OBJECTIVE: To compare estimates of adiposity by dual emission X-ray absorptiometry (DXA), skinfolds and body mass index (BMI); and to evaluate the relation of these measures to cardiovascular risk in adolescents. DESIGN: In a cohort of adolescents participating in a longitudinal study of insulin resistance, Slaughter formulas were used to estimate adiposity from skinfolds and DXA was used to estimate adiposity as % body fat (%BF) and fat mass (FBM). BMI, blood pressure, lipids and insulin resistance were measured. SUBJECTS: Male and female, 11 - 17 y old (n = 130). MEASUREMENTS: To compare DXA with two office-based methods of assessing fatness and cardiovascular risk. RESULTS: Slaughter estimates were highly correlated with DXA (%BF r = 0.92, P = 0.0001; FBM r = 0.96, P = 0.0001). Correlations were similar in heavy and thin children. BMI was also highly correlated with DXA (%BF r = 0.85, P = 0.0001; FBM r = 0.95, P = 0.0001), and these relations were stronger in heavy than thin children. BMI and the Slaughter formulas were similar to DXA in their relations to cardiovascular risk factors. CONCLUSIONS: Adiposity by BMI and Slaughter formulas are highly correlated with DXA and similarly related to cardiovascular risk factors. BMI is easy to obtain and is an acceptable method for initial office estimation of body fatness. BMI and skinfolds compare well with DXA in predicting adverse cardiovascular risk profile.