Body composition. Prediction of normal body potassium, body water and body fat in adults on the basis of body height, body weight and age

Abstract

In 134 males and 242 females, aged 20-70 years, most of them randomly selected from population studies, the body composition was estimated from the measurements of body height (BH), body weight (BW), total body potassium (TBK) and total body water (TBW). TBK was measured with isotope dilution technique using 42K or determined as 40K in a whole body counter. TBW was determined with an isotope dilution technique using tritiated water, assayed in urine or plasma. From these data, body cell mass (BCM), intra- and extra-cellular water (ICW and ECW, resp.) and body fat (BF) were calculated for each individual. Significant correlations were found between age versus TBK, ECW, BF and ECW/ICW; between BW versus TBK, TBW, ECW, BF and ECW/ICW; (females only) and between BH versus TBK, TBW, ECW (females only) and ECW/ICW. For the prediction of TBK, TBW and BF, multiple regression equations based on BW, BH and age are given. These equations are also presented diagrammatically. The problems with the methods used are considered as well as the applicability of the formulas for the calculation of BCM etc. The predictive value of the results when both TBW and TBK are used for the calculation of body composition data is discussed and compared with similar results, based on TBW or TBK only. It is concluded, that the most reliable method for calculation of BF is to estimate both TBW and TBK.

Body composition in patients with short bowel syndrome: An assessment by bioelectric impedance spectroscopy (BIS) and dual–energy absorptiometry (DXA)

“…For further comparison, a prediction of TBW (TBW-PRE) was calculated according to a formula suggested by Bruce (Bruce et al, 1980). …”

“…Prediction of TBW Predicted TBW (PRE) was calculated according to a modified formula derived by Bruce et al (1980). The formula uses body weight and height, sex and age and gives an estimate of TBW, r (male)¼0.755, r (female)¼0.773.…”

“…The formula uses body weight and height, sex and age and gives an estimate of TBW, r (male)¼0.755, r (female)¼0.773. The formula values were obtained in a healthy population (n¼476) from a fourcompartment model based on total body potassium and tritiated water (Bruce et al, 1980). The dilution technique using tritiated water overestimates TBW by 4-5% (Schoeller, 1992).…”

Height and body weight in the elderly. I. A 25-year longitudinal study of a population aged 70 to 95 years

“…However, the decline of height with the ageing process can also lead to an overestimation of body Height and body weight in the elderly DK Dey et al mass index in the elderly (de Groot et al, 1996). The changing patterns of body fat distribution and body composition with age (Bruce et al, 1980;Steen et al, 1985;Chumlea & Baumgartner, 1989), also affects the signi®-cance of BMI values for assessing the health and nutritional status of elderly persons.…”

“…Understanding changes in body composition accompanying the ageing process and its health and nutritional implications is important to both basal gerontological knowledge and nutritional support of the elderly (Steen, 1988;Chumlea & Baumgartner, 1989). Body composition changes with ageing (Bruce et al, 1980;Steen et al, 1985). Some general trends including an increase of body weight in middle age (Cornoni-Huntley et al, 1991;Bjo Èrkelund et al, 1997) followed by a decrease in stature, weight and body cell mass at older ages (Going et al, 1995) have been described.…”