Determining bone and total body mineral content from body density and bioelectrical response spectroscopy

1 Neurosciences' Neuromuscular Laboratory, SD3/Space and Life Sciences Research Laboratories, National Aeronautics and Space Administration Johnson Space Center, Houston 77058; 3 Stable Isotope Program, United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston 77030; 4 University Space Research Association, Houston 77058; 5 Aerospace Consultant Enterprises, Houston, Texas 77059; and 2 Department of Foods and Nutrition, Purdue University, West Lafayette, Indiana 47907 We hypothesized that one could assess total body mineral (TBM) and bone mineral content (BMC) from measurements of body density and bioelectrical response spectroscopy (BRS)-determined total body water by using a three-compartment (3C) model. We compared TBM and BMC computed from measurements of water ( 2 H 2 O dilution or BRS) and body density (underwater weighing) with [4-compartment (4C)] and without (3C) mineral (dual X-ray absorptiometry) in 15 women and 16 men. BRS used multifrequency or single-frequency estimates of water. Mean differences between the 3C and 4C models ranged from 6.1 to 2.2%. Correlations between models were 0.82-0.91. Standard errors of the estimate of 8.5-9.3% were within the range of those previously reported, i.e., 4.9-13%. Use of BRS did not significantly decrease the strength of the correlations between the models. A significant mean difference (only in women) was found only with 3C single-frequency BRS estimates of TBM and BMC. We concluded that investigators can assess TBM and BMC 3C multifrequency BRS estimates in men and women. multicompartment models; body composition; underwater weighing; osteoporosis