Empirically derived new equations for calculating body fat percentage based on skinfold thickness and midarm circumference in preschool Indian children

We wanted to develop and apply new equations based on skinfold and midarm measurements for estimating %fat in preschool children suitable for field use. Prediction equations were developed on preschool-aged urban boys (n = 100) and girls (n = 84). Skinfolds at four sites and midarm measurements were regressed on %fat derived from equations based on height and weight and from bioelectrical impedance analysis (BIA; resistance at 50 kHz). These equations were applied: 1) to 12 children in whom the %fat was determined using D2O dilution, and 2) to 50 children in whom their %fat was derived using height-weight and BIA equations. The 95% limits of agreement (mean +/- 2 SD) for %fat derived by anthropometry and by new equations were within 1.7% in boys (r = 0.85; P < 0.001) and girls (r = 0.90; P < 0.001) and by BIA and new equations were within 1.5% in boys (r = 0.82; P < 0.001) and 2% in girls (r = 0.88; P < 0.001). For %fat measured by D2O dilution and new equations, 95% limits of agreement was within 1.3% (r = 0.98; P < 0.001). In 50 children 95% limits of agreement between anthropometry and new equations were within 1.8% in boys (r = 0.88; P < 0.001) and 1.4% in girls (r = 0.92; P < 0.001) and between BIA and new equations were within 1% in boys (r = 0.91; P < 0.001) and 1.5% in girls (r = 0.89; P < 0.001). The new equations for measuring %fat based on midarm circumference and skinfold measurements are rapid and accurate for South Asian children and should be useful for prediction of body composition and nutritional survey in field studies.