PREDICTION OF BODY DENSITY FROM SKINFOLD THICKNESS IN ELDERLY SUBJECTS - ARE THE EXISTING EQUATIONS VALID

In 33 healthy elderly subjects, body density was measured using hydrod ensitometry and predicted from the sum of four skinfold thicknesses. I n the men, mean measured density was 1.045 kg/l and mean predicted den sity 1.041 kg/l, with bias and limits of agreement 0.004 (+/- 0.016) k g/l and 95% confidence interval (CI) for the difference 0.001-0.008 kg /l. In the women, mean measured density was 1.012 kg/l and mean predic ted density 1.020 kg/l, and 95% CI for the difference was -0.016-0.000 kg/l. The bias was therefore in the opposite direction in women than men, and limits of agreement were wider (-0.008 +/- O.030 kg/l) in the women. Biases in prediction of density lead to systematic error in es timation of body fatness in elderly subjects, and this systematic erro r is more likely to be of practical significance in women than men.