Potassium per kilogram fat-free mass and total body potassium: predictions from sex, age, and anthropometry

2003 ◽  
Vol 284 (2) ◽  
pp. E416-E423 ◽  
Author(s):  
Ingrid Larsson ◽  
Anna Karin Lindroos ◽  
Markku Peltonen ◽  
Lars Sjöström
Keyword(s):  
Fat Free Mass ◽  
Whole Body ◽  
Primary Study ◽  
Study Group ◽  
Validation Group ◽  
Total Body Potassium ◽  
X Ray ◽  
Body Counting ◽  
Total Body ◽  
Whole Body Counting

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; FFMDEXA). 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 FFMDEXA 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.

scholarly journals Chemical composition of organs of children who died from malnutrition

1969 ◽  
Vol 23 (4) ◽  
pp. 783-790 ◽  
Author(s):  
G. A. O. Alleyne ◽  
D. Halliday ◽  
J. C. Waterlow ◽  
B. L. Nichols
Keyword(s):  
Magnesium Content ◽  
The Body ◽  
Liver Fat ◽  
Whole Body ◽  
Total Body Potassium ◽  
Malnourished Children ◽  
Body Counting ◽  
Total Body ◽  
Whole Body Counting ◽  
The Brain

1. Chemical analysis was carried out on samples of brain, liver, skeletal muscle, heart and kidney obtained from children who died of malnutrition. Total body potassium was measured before autopsy by the ‘whole body counting’ technique.2. There was a marked increase in liver fat, and the brain contributed a higher percentage of the body-weight in the more severely malnourished children.3. All the organs had approximately the same concentrations of non-collagen nitrogen. The proportion of collagen was highest in muscle.4. All organs were depleted of potassium, but the muscle was most severely affected. Brain potassium as a percentage of total body potassium was higher than normal in the most severely potassium depleted children.5. Measurements of tissue magnesium showed that there was no difference in magnesium content of tissues when expressed in terms of non-collagen nitrogen. When compared with normal values, muscle was magnesium depleted. The potassium to magnesium ratio was lowest in muscle.

Total Body Potassium in Children, with Particular Reference to Coeliac Disease

1975 ◽  
Vol 49 (2) ◽  
pp. 133-137
Author(s):  
K. Boddy ◽  
Priscilla C. King ◽  
F. Carswell
Keyword(s):  
Coeliac Disease ◽  
Whole Body ◽  
Total Body Potassium ◽  
Body Counting ◽  
Total Body ◽  
Whole Body Counting

1. Total body potassium was measured, by whole-body counting, in children with coeliac disease and in children not having this disease, matched as closely as possible with respect to sex, height, weight and age. 2. The measured total body potassium in children with coeliac disease was not significantly different from that in the matched children. 3. The problems associated with such measurements, particularly those of interpretation, are considered.

Total Body Potassium and Body Fat Estimation in Relationship to Height, Sex, Age, Malnutrition and Obesity

1975 ◽  
Vol 48 (5) ◽  
pp. 431-440 ◽  
Author(s):  
C. J. Edmonds ◽  
B. M. Jasani ◽  
T. Smith
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Body Fat ◽  
Fat Free Mass ◽  
Whole Body ◽  
Regression Equations ◽  
Total Body Potassium ◽  
Normal Individuals ◽  
Males And Females ◽  
Total Body

1. Total body potassium was estimated by 40K measurement with a high-sensitivity whole-body counter in normal individuals over a wide age range and in patients who were obese or were grossly wasted as a result of various conditions which restricted food intake. 2. Potassium concentration (mmol/kg body weight) fell with increasing age over 30 years in both normal males and females, but when individuals of different age groups were matched for height, a significant fall in total body potassium with increasing age was observed only in males. Total body potassium of females was about 75% that of males of similar height when young, the sex difference decreasing with ageing. In the normal population, total body potassium was significantly correlated with height and with weight; regression equations for various relationships are given. 3. Fat-free mass was estimated from total body potassium, values of 65 and 56 mmol of potassium/kg fat-free mass being used for males and females respectively. Body fat estimated by this method correlated well with skinfold measurements over a wide range of body weight but in malnourished individuals having inadequate food intake there was considerable discrepancy and present formulae for estimating fat-free mass from total body potassium appear unsatisfactory in malnutrition. Considerable differences between expected and observed values of total body potassium were found in muscular individuals and in normal individuals who were thin but whose body weight was relatively constant. 4. The patients with malnutrition were low both in body fat as estimated by skinfold thickness and in total body potassium estimated on the basis of height. Plasma potassium was, however, normal and potassium supplements did not increase the total body potassium. 5. Total body potassium of obese individuals was not significantly different from that of normal weight individuals on the basis of height. Total body potassium fell on weight reduction with a very low energy diet of 1260 kJ (300 kcal.) daily but changed little with a 3300 kJ (800 kcal.) diet over several months' observation. 6. For overweight, obese individuals, total body potassium was best predicted from the individual's height. For those whose body weight was less than expected, the use of weight gave the best prediction but the error was considerable when the weight deviation was large.

The Measurement of Total Body Potassium in Patients on Peritoneal Dialysis

2001 ◽  
Vol 21 (3_suppl) ◽  
pp. 163-167 ◽  
Author(s):  
Graham Woodrow ◽  
Brian Oldroyd ◽  
Antony Wright ◽  
W. Andrew Coward ◽  
John H. Turney ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Deuterium Oxide ◽  
Cell Mass ◽  
Fat Free Mass ◽  
Whole Body ◽  
Body Cell Mass ◽  
Total Body Potassium ◽  
Noninvasive Technique ◽  
Body Cell ◽  
Total Body

♦ Objectives To assess the validity of measuring total body potassium (TBK) to estimate fat-free mass (FFM) and body cell mass (BCM) in patients on peritoneal dialysis (PD). ♦ Methods We studied 29 patients on PD (14 men, 15 women) and 30 controls (15 men, 15 women). We calculated TBK by using a whole-body counter to measure 1.46 MeV gamma-ray emissions from naturally occurring 40K. We measured total body water (TBW) by deuterium oxide dilution, and extracellular water (ECW) from bromide dilution. These measurements allowed us to estimate intracellular water (ICW), fat-free mass dilution (FFMDilution), and body cell mass dilution (BCMDilution). ♦ Results The FFMTBK in male PD patients (55.7 ± 7.0 kg) did not differ from that in male controls (57.0 ± 10.9 kg). The FFMTBK in female PD patients (38.4 ± 6.8 kg) was less than that in female controls (44.7 ± 4.5, p < 0.01). The FFMDilution did not differ from the FFMTBK. Correlation of FFMTBK and FFMDilution was r = 0.90, p < 0.0001 for all subjects; r = 0.90, p < 0.0001 for PD patients; and r = 0.90, p < 0.0001 for controls. Bland–Altman comparison of FFMDilution with FFMTBK in individuals showed bias 0.6 kg, range –8.5 kg to 9.7 kg for the whole group; bias 1.4 kg, range –7.9 kg to 10.7 kg for PD patients; and bias –0.2 kg, range –9.0 kg to 8.6 kg for controls. The BCMTBK in male PD patients (30.1 ± 4.5 kg) did not differ from that in male controls (31.9 ± 6.2 kg). The BCMTBK in female PD patients (19.0 ± 4.4 kg) was less than that in female controls (23.1 ± 2.9 kg, p < 0.01). The BCMDilution results did not differ from those for the BCMTBK. Correlation of BCMTBK and BCMDilution was r = 0.90, p < 0.0001 for all subjects; r = 0.87, p < 0.0001 for PD patients; and r = 0.93, p < 0.0001 for controls. Bland–Altman comparison of BCMDilution with BCMTBK in individuals showed bias 0.1 kg, range –5.9 kg to 6.1 kg for the whole group; bias 0.0 kg, range –6.9 kg to 6.9 kg for PD patients; and bias 0.1 kg, range –5.0 kg to 5.2 kg for controls. The [K+]ICW did not differ between PD patients and controls (148.0 ± 25.1 mmol/L vs 148.1 ± 14.3 mmol/L, p = nonsignificant). ♦ Conclusions Total body potassium is a valid, noninvasive technique for measuring FFM and BCM in PD patients. In our PD patient group, depletion of FFM and BCM as compared with controls was identified in the women but not in the men.

Differences in skeletal and muscle mass with aging in black and white women

2000 ◽  
Vol 278 (6) ◽  
pp. E1153-E1157 ◽  
Author(s):  
John F. Aloia ◽  
Ashok Vaswani ◽  
Martin Feuerman ◽  
Mageda Mikhail ◽  
Ruimei Ma
Keyword(s):  
Neutron Activation Analysis ◽  
Black Women ◽  
Muscle Mass ◽  
White Women ◽  
Whole Body ◽  
Skeletal Mass ◽  
Body Counting ◽  
Total Body ◽  
Gamma Neutron Activation ◽  
Whole Body Counting

Previous cross-sectional studies using delayed gamma neutron activation analysis and whole body counting suggested that the relationship of total body calcium (TBCa) to total body potassium (TBK) (muscle mass, body cell mass) remained constant with age. This led to the hypothesis that the muscle mass and skeletal mass compartments are integrated in their response to aging. It had also been hypothesized that loss of skeletal and muscle mass was similar between races. In the current study, delayed gamma neutron activation analysis and whole body counting were performed on 90 black and 143 white women 20–69 yr of age. Black women had higher TBCa and TBK values than white women, even when the data were adjusted for age, height, and weight. TBCa was correlated with height and TBK with weight. The estimated decline of skeletal mass (TBCa) from 20 to 70 yr was 18% in black women and 19% in white women. However, the lifetime decline of TBK was only 8% for black women, compared with 22% for white women. Black women may lose TBK more slowly than TBCa with aging, compared with white women. In particular, correlation of TBCa and age was similar for blacks and whites ( r = −0.44 and r = −0.54, respectively). However, for TBK these correlations were r = −0.14 and r = −0.42. These data confirm a higher musculoskeletal mass in black women and suggest that the loss of muscle mass with age may be lower in black than in white women. These ethnic differences do not support the hypothesis of an integrated musculoskeletal system, so that these two components should be considered separately. A prospective study is needed to confirm these findings.

Correlation between skeletal calcium mass and muscle mass in man

1975 ◽  
Vol 38 (3) ◽  
pp. 455-460 ◽  
Author(s):  
J. K. Ellis ◽  
S. H. Cohn
Keyword(s):  
Metabolic Disorders ◽  
Normal Values ◽  
Whole Body ◽  
Skeletal Mass ◽  
Metabolic States ◽  
Body Counting ◽  
Total Body ◽  
Whole Body Counting ◽  
Skeletal Calcium ◽  
Age Range

The measurements of total body potassium (TBK) and calcium (TBCa) were made on 317 subjects by the techniques of whole-body counting and total-body neutron activation analysis (TBNAA), respectively. The TBK/TBCa ratios are constant for normals over the age range studied. The males have more cellular mass (TBK) per unit skeletal mass (TBCa) than the females, as indicated by their respective TBK/TBCa ratios, 0.122 +/- 0.008 (1 SD), and 0.100 +/- 0.007 (1 SD). In general, patients with various metabolic disorders tend to follow the physiological trend found in the normals. In a number of metabolic disorders, the loss of TBK was usually approximately 60% of that of the TBCa when expressed in terms of the predicted normal values. This suggests that the mechanism causing the loss of calcium in physiological and altered metabolic states simultaneously involves both the skeleton and its associated musculature.

Studies of Calcium Absorption in Man Using a CD-2 Whole-Body Counter

1977 ◽  
Vol 16 (04) ◽  
pp. 163-167
Author(s):  
K. Bakos ◽  
Věra Wernischová
Keyword(s):  
Calcium Absorption ◽  
Whole Body ◽  
Control Group ◽  
Absorption Process ◽  
Whole Body Counter ◽  
Absorption Studies ◽  
Body Counting ◽  
Calcium Load ◽  
Calcium Malabsorption ◽  
Whole Body Counting

SummaryWhole-body counting makes an important contribution of radioisotope techniques to ȁEin vivo“ absorption studies, in comparison with other methods. In a large number of subjects, the method was tested for its usefulness in the diagnosis of calcium malabsorption. The effects of drugs, of the calcium load in the gut and of the whole-body content of calcium on the absorption process were studied in a control group.

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