Comparison of methods for estimating body composition in young and elderly women

Estimates of percent body fat and fat-free mass (FFM) were made in healthy young and elderly female subjects using five different methods: bioelectrical impedance analysis (BIA); regression equations involving skinfold measurements at two (Durnin and Womersley; SKF-DW) or three (Jackson and Pollack; SKF-JP) sites; the body mass index (BMI); and an equation relating height and weight to total body water (TBW). Three of the five methods indicated that the percent body fat was significantly greater in the elderly age group. Similarly, three methods estimated FFM values that were significantly lower in the elderly group. In the young group the SKF-DW and TBW methods produced percent fat estimates significantly higher than the other three methods. In the elderly group the percent fat estimates were as follows: SKF-DW greater than BIA greater than SKF-JP = TBW greater than BMI. FFM estimates in both age groups were in inverse rank order to the percent fat estimates. In elderly subjects SKF-DW produced results closest to those from BIA, whereas in young subjects SKF-JP provided the best agreement with the BIA procedure.