Potassium per kilogram fat-free mass and total body potassium: predictions from sex, age, and anthropometry.
Total body potassium (TBK) is located mainly intracellularly and constitutes an index of fat-free mass (FFM). The aim was to examine whether TBK and the TBK-to-FFM ratio (TBK/FFM) can be estimated from sex, age, weight, and height. A primary study group (164 males, 205 females) and a validation group (161 and 206), aged 37-61 yr, were randomly selected from the general population. TBK was determined by whole body counting, and FFM was obtained by dual-energy X-ray absorptiometry (DEXA; FFM(DEXA)). The primary study group was used to construct sex-specific equations predicting TBK and TBK/FFM from age, weight, and height. The equations were used to estimate TBK and TBK/FFM in the validation group. The estimates were compared with measured values. TBK in different age ranges was predicted, with errors ranging from 5.0 to 6.8%; errors for TBK/FFM ranged from 2.7 to 4.8%, respectively. By adding FFM(DEXA) as a fourth predictor, the error of the TBK prediction decreased by approximately two percentage units. In conclusion, TBK and TBK/FFM can be meaningfully estimated from sex, age, weight, and height.
Larsson
Ingrid
I
Department of Body Composition and Metabolism, The Sahlgrenska Academy at Göteborg University, SE-41345 Göteborg, Sweden.
Lindroos
Anna Karin
AK
Peltonen
Markku
M
Sjöström
Lars
L
D015502:Absorptiometry, Photon; D000273:Adipose Tissue; D000328:Adult; D000367:Age Factors; D001827:Body Height; D001835:Body Weight; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011188:Potassium / Q000032:analysis*; D011237:Predictive Value of Tests; D012044:Regression Analysis; D012737:Sex Factors
D011188:Potassium