Objective: To determine which anthropometric measure best correlates with change in fat mass (FM) over time.
Methods: The authors performed a retrospective cohort study of 76 obese patients (mean body mass index [BMI] 38 kg/m(2) and mean age 13 years) presenting to an obesity clinic between 2005 and 2010. For each patient, during 2 visits, FM was measured by bioelectrical impedance analysis and the following measures obtained: BMI, waist circumference, hip circumference, and neck circumference. Correlation coefficients and linear regression analyses were calculated to examine the relationship between each measure and FM.
Results: Change in BMI correlated better with change in FM than any other measure and had the strongest effect on change in FM (P < .01, R (2) = .887). The best regression model included BMI only (R (2) = .891); without BMI, the model was significantly worse (R (2) = .521).
Discussion: In the clinical management of obese children, BMI is an adequate measure of change in FM.