Body composition of Peruvian children with short stature and high weight-for-height. I. Total body-water measurements and their prediction from anthropometric values.

Total body water (TBW) was measured by 18O dilution in 139 undernourished, preschool Peruvian children with high weight-for-height. Values for TBW as a percent of body weight were relatively high, averaging 67.4 +/- 6.4%. Depending upon the method of calculation, mean values for the sample population for percent fat ranged from 9.4-18.5%. Regression of TBW on lean body mass suggested that hydration of the fat-free body was higher than for normally nourished children of comparable age. Thus, the increased weight-for-height in these children did not result from increased fat tissue, but from increased hydration of the fat-free body. TBW was most highly correlated with height and weight, both with r = 0.95. Equations predicting TBW from either height or weight were significantly different from those developed by other investigators to predict TBW for normal, well-nourished American children.