Validity of skinfold thickness measures of formerly obese adults

Abstract

To assess the validity of skinfold thickness estimates of body fatness in formerly morbid obese adults, 23 patients (17 women, 6 men) who had completed a protein-sparing modified fast were studied. Mean ± SD weight loss was 60.7 ± 20.6 kg for men and 42.6 ± 11.5 kg for women. Body density and percent body fatness were determined after weight loss according to four commonly used skinfold equations: Pollock (P); Durnin-Rahaman (D-R); Durnin-Womersley (D-W); and, Jackson-Pollock (J-P). The validity of these measurements was assessed by hydrostatic weighing, which revealed a percent body fatness of 20.4 ± 6.5 for men and 29.8 ± 8.4 for women. The mean difference and total error (square root of the x̄ of squared deviations) between skinfold predicted and hydrostatically-determined percent body fatness for each skinfold equation were: P, 2.0 and 4.9; D-R, 4.2 and 6.6; D-W, 7.1 and 8.4; and J-P, 0.7 and 4.4. With the exception of the latter equation, all significantly overestimated (p < 0.01) hydrostatically-determined percent body fatness. Conclusion: Select skinfold equations may result in a marked overestimation of body fatness in formerly obese patients.