Percent body fat estimation from skin fold thickness in the elderly. Development of a population-based prediction equation and comparison with published equations in 75-year-olds.

Objective: To develop a prediction equation for percent body fat (BF%) from skin fold thickness in a random sample of free-living 75-year-olds and to compare with published equations for the elderly.
Setting: Goteborg part of the Nordic Research on Aging (NORA) study in 1991/92.
Subjects & Methods: Anthropometric measurements were performed in 286 participants (125 males,161 females) and body composition was estimated by four compartment model (4C) from total body water (TBW) and total body potassium (TBK) in every alternative subjects. BF % predicted from skin fold thickness (BFSF) was validated against BF % estimated from 4C model (BF4C) and was compared with BFSF and BF % predicted from equations by Durnin and Womersley, 1974 (BFDW), Deurenberg et al.,1989 (BFPD) and, Visseretal.,1994(BFMV), respectively.
Results: The BFSF correlated well with BF4C (r = 0.86, SEE = 4.05). Compared to BF4C, both BFPD and BFMV over estimated BF % by 3.26 and 3.63 in males and 9.56 and 9.23 in females, respectively. BFDW underestimated BF % in females by 1.06 and overestimated by 3.12 in males. BFSF showed best agreement with BF4C, where the 95 % of differences lie between +/- 7.4 in males and +/- 8.7 in females, respectively.
Conclusion: BF % predicted from skin fold thickness correlated well with estimated BF % in 75-year-olds. Different prediction equations gave different values for BF % and population-specific prediction equations seem preferable in the elderly population.