Validation of body composition measured by skinfold thickness technique and bioelectrical impedance analysis versus dual- energy X-ray absorptiometry among elderly with sarcopenia

Background. An accurate measurement of body composition among the elderly is important to diagnose various clinical conditions associated with muscle loss (e.g. sarcopenia and cachexia). Methods. 55 men and 23 women (mean age, 66.9 years) were included in this validation study. The skinfold thickness technique (SKF) and bioelectrical impedance analysis (BIA) were validated against dualenergy X-ray absorptiometry (DEXA) in terms of fat mass percentage (%FM) and fat-free mass (FFM) among lean and obese sarcopenic elderly. Three different machines were used for BIA: Omron HBF-510, Tanita BC-418, and Maltron-916. Results. Agreement between DEXA and the Maltron-916 was the best, with mean bias in %FM being 2.8% and 0.6%, and in FFM being -1.7 kg and -1.2 kg for the lean and obese sarcopenics, respectively. Respectively for Tanita BC-418, Omron-HBF-510, and SKF, the mean biases in %FM were 3.4%, 5.2%, and 6.4% among lean sarcopenics, and 1.8%, 8.3%, and 9.1% among obese sarcopenics, whereas the mean biases in FFM were -2.2 kg, -3.4 kg, and -3.9 kg among the former, and -2.1 kg, -6.8 kg, and -7.4 kg among the latter. Accuracy in assessing %FM and FFM was higher in the obese than lean sarcopenics. Conclusions. Maltron-916 agreed with DEXA the most in measuring body composition, compared with the other BIA machines and SKF. Nonetheless, caution should be exercised when assessing lean sarcopenic elderly people.