W.D. van Marken Lichtenbelt

The validity of predicted body fat percentage from body mass index and from impedance in samples of five European populations

Objectives: To test and compare the validity of a body mass index (BMI)-based prediction equation and an impedance-based prediction equation for body fat percentage among various European population groups.Design: Cross-sectional observational study.Settings: The study was performed in five different European centres: Maastricht and Wageningen (The Netherlands), Milan and Rome (Italy) and Tampere (Finland), where body composition studies are routinely performed.Subjects: A total of 234 females and 182 males, aged 18–70u2005y, BMI 17.0–41.9u2005kg/m2.Methods: The reference method for body fat percentage (BF%REF) was either dual-energy X-ray absorptiometry (DXA) or densitometry (underwater weighing). Body fat percentage (BF%) was also predicted from BMI, age and sex (BF%BMI) or with a hand-held impedance analyser that uses in addition to arm impedance weight, height, age and sex as predictors (BF%IMP).Results: The overall mean (±s.e.) bias (measured minus predicted) for BF%BMI was 0.2±0.3 (NS) and−0.7±0.3 (NS) in females and males, respectively. The bias of BF%IMP was 0.2±0.2 (NS) and 1.0±0.4 (P<0.01) for females and males, respectively. There were significant differences in biases among the centres. The biases were correlated with level of BF% and with age. After correction for differences in age and BF% between the centres the bias of BF%BMI was not significantly different from zero in each centre and was not different among the centres anymore. The bias of BF%IMP decreased after correction and was significant from zero and significant from the other centres only in males from Tampere. Generally, individual biases can be high, leading to a considerably misclassification of obesity. The individual misclassification was generally higher with the BMI-based prediction.Conclusions: The prediction formulas give generally good estimates of BF% on a group level in the five population samples, except for the males from Tampere. More comparative studies should be conducted to get better insight in the generalisation of prediction methods and formulas. Individual results and classifications have to be interpreted with caution.European Journal of Clinical Nutrition (2001) 55, 973–979

Comparison of body composition methods: a literature analysis

Objective: To examine the comparability of different methods to assess percentage body fat (BF%) against underwater weighing (UWW). Design: A meta-analysis on 54 papers, published in 1985–96, on healthy, adult Caucasians. Methods: The mean BF% from different studies were treated as single data points. In addition to UWW, the studies included one or more of the following methods: 3- or 4-component model, dual-energy X-ray absorptiometry (DXA), dual-energy photon absorptiometry, isotope dilution, bioimpedance (BIA), skinfolds or near-infrared interactance (NIR). Within each of the methods, the analyses were done separately for different mathematical functions, techniques or instruments. Main outcome measures: Bias (mean difference) and error (s.d. of difference) between BF% measured by UWW and the other methods. Results: The 4-component model gave 0.6 (95% confidence interval for the mean, CI: 0.1 to 1.2) BF% higher results than UWW. Also the 3-component model with body density and total body water (+1.4 BF%, 95% CI: +0.3 to +2.6), deuterium dilution (+1.5 BF%, 95% CI: +0.7 to +2.3), DXA by Norland (+7.2 BF%, 95% CI: 2.6 to 11.8) and BIA by Lukaski et al. (+2.0 BF%, 95% CI: 0.2 to 3.8) overestimated BF%, whereas BIA by Valhalla Scientific (−2.6 BF%, 95% CI: −4.5 to −0.6) and skinfold equations by Jackson et al. (−1.20, 95% CI: −2.3 to −0.1) showed a relative underestimation. The mean bias for the skinfold equation by Durnin & Womersley, against UWW, was 0.0 BF% (95% CI: −1.3 to 1.3). The correlation between the size of measurement and the mean difference was significant for only NIR (r=−0.77, P=0.003). Conclusions: The difference between any method and UWW is dependent on the study. However, some methods have a systematical tendency for relative over- or underestimation of BF%.

Energy metabolism in humans at a lowered ambient temperature

Objective: Assessment of the effect of a lowered ambient temperature, ie 16°C (61°F), compared to 22°C (72°F), on energy intake (EI), energy expenditure (EE) and respiratory quotient (RQ) in men.Design: Randomized within-subject design in which subjects stayed in a respiration chamber three times for 60u2005h each, once at 22°C, and twice at 16°C, wearing standardized clothing, executing a standardized daily activities protocol, and were fed in energy balance (EBI): no significant difference between EE and EI over 24u2005h). During the last 24u2005h at 22°C, and once during the last 24u2005h at 16°C, they were fed ad libitum.Subjects: Nine dietary unrestrained male subjects (ages 24±5u2005y, body mass index (BMI) 22.7±2.1u2005kg/m2, body weight 76.2±9.4u2005kg, height 1.83±0.06u2005m, 18±5% body fat).Results: At 16°C (EB), EE (total 24u2005h EE) was increased to 12.9±2.0u2005MJ/day as compared to 12.2±2.2u2005MJ/day at 22°C (P<0.01). The increase was due to increases in sleeping metabolic rate (SMR; the lowest EE during three consecutive hours with hardly any movements as indicated by radar): 7.6±0.7 vs 7.2±0.7u2005MJ/day (P<0.05) and diet-induced thermogenesis (DIT; EE-SMR, when activity induced energy expenditure as indicated by radar=0): 1.7±0.4 vs 1.0±0.4u2005MJ/day (P<0.01). Physical activity level (PAL; EE/SMR) was 1.63–1.68. At 16°C compared to at 22°C, rectal, proximal and distal skin temperatures had decreased (P<0.01). RQ was not different between the two ambient temperature situations. During ad libitum feeding, subjects overate by 32±12% (at 22°C) and by 34±14% (at 16°C). Under these circumstances, the decrease of rectal temperature at 16°C was attenuated, and inversely related to percentage overeating (r 2=0.7; P<0.01).Conclusion: We conclude that at 16°C, compared to 22°C, energy metabolism was increased, due to increases in SMR and DIT. Overeating under ad libitum circumstances at 16°C attenuated the decrease in rectal core body temperature.

Assessment of energy expenditure in overweight women.

PURPOSEnTo compare field measures of average daily energy expenditure (ADEE) against criterion data by the doubly labeled water method (DLW) in overweight women.nnnMETHODSnThe subject were 20 overweight (BMI 29.9 +a- 3.0 kg.m-2) premenopausal women. Energy expenditure was measured by DLW and by the factorial method (activity diary, two techniques differing by method to obtain resting energy expenditure, REE), heart-rate monitoring (HR, two techniques differing by the FLEX-point to discriminate sedentary and activity HR), accelerometer, and pedometer.nnnRESULTSnThe ADEE(DLW) was 10.26 +a- 1.1 MJ.d-1. The mean bias (ADEE by the alternative minus ADEE(DLW) was smallest for the accelerometer (+ 0.08 +a- 1.63 MJ) and HR-FLEX10 (+ 0.11 +a- 1.67 MJ). The HR-FLEX(0) technique (lower FLEX-point) overestimated ADEE by + 1.18 (+a- 1.97 MJ). However, the random error (SD of bias) was smaller for both factorial techniques (REE measured: -0.48 +2- 0.81 MJ; REE calculated from the WHO equation: -0.22 +2- 0.88 MJ).nnnCONCLUSIONnThe results show that simple factorial methods may assess ADEE with small random errors in population with a rather narrow range of physical activity. The accelerometer and HR with the higher FLEX-point have comparable results with smaller bias but larger random error compared with the factorial techniques.

Physical activity, body composition and bone density in ballet dancers

The main purpose of the present study was to examine factors that affect bone mineral density (BMD) in female ballet dancers. Training history, Ca intake, body composition, total body BMD (TBMD) and site-specific BMD, and bone mineral content were described in twenty-four female ballet dancers (mean age 22.6 (SD 4.5) years). Training history was determined by questionnaires, Ca intake by 7 d dietary record, BMD and bone mineral content by dual-energy X-ray absorptiometry (DXA), total body water by 2H dilution, extracellular water by bromide dilution, body fat by underwater weighing (UWW; two-component model), DXA, and the four-component (4C) model. Dancers had a significantly lower body mass index (BMI 18.9 (SD 1.0) kg/m2) than controls (21.3 (SD 1.9) kg/m2), with significantly lower percentage body fat (17.4 (SD 3.9) v. 24.4 (SD 5.1)) but comparable fat-free mass. Mean TBMD (1.147 (SD 0.069) g/cm2) was significantly higher (6%) compared with that of a reference population. These high values could be attributed to the high BMD of legs and pelvis, the weight-bearing sites of the dancers body. No relationship was found between age, start of ballet classes, period (years) of dancing, Ca intake, and BMD (total and site-specific). However, TBMD was positively related to BMI, and negatively related to the age of menarche. BMD of the legs was significantly related to BMI, and negatively related to the age of menarche. BMD of the legs was significantly related to daily period (h) of training. Depending on the method used the percentage body fat ranged from 16.4 (by DXA) to 18.3 by the 4C model. These differences were significantly related to the TBMD. Percentage body fat by the different methods was not significantly different, except for DXA and 4C model. The present study showed that, despite the factors that have a negative effect on BMD, such as low body mass and late menarche, BMD in female ballet dancers was relatively high. These high values were probably caused by high levels of weight-bearing physical activity.

Bodybuilders' Body Composition: Effect of Nandrolone Decanoate

INTRODUCTIONnThe use of androgenic-anabolic steroids (AAS) among bodybuilders to increase muscle mass is widespread. Nandrolone decanoate (ND) is one of the most popular misused AAS, although the effects on body composition are equivocal. Therefore, the purpose of this study was to determine the effect of ND on body composition in male bodybuilders, with special reference to muscle mass alterations.nnnMETHODSnUsing a randomized double-blind placebo-controlled design, 16 experienced male bodybuilders (age: 19-44 yr) either received ND (200 mg.wk(-1), intramuscularly) or placebo for 8 wk. Body composition was assessed using the four-component model, combining results from underwater weighing, dual-energy x-ray absorptiometry (DXA), and deuterium dilution. Total bone mineral content and density were measured using DXA. Water compartments (extracellular water [ECW] and intracellular water [ICW]) were determined using deuterium dilution and bromide dilution.nnnRESULTSnND administration resulted in significant increments of body mass (+2.2 kg), fat-free mass (FFM: +2.6 kg), and total body water (+1.4 kg). No significant changes in fat mass, percentage fat, ECW, ICW, ECW/ICW ratio, hydration of the FFM, and on bone mineral measurements were observed.nnnCONCLUSIONSnThe results show that the administration of 200 mg.wk(-1) of ND (intramuscularly) for 8 wk significantly increased body mass and FFM, whereas fat mass, bone mineral content, bone mineral density, and the hydration of the FFM remained unaffected. These data indicate that the changes can be attributed to an increase of muscle mass.

Gender specific alterations of body composition in patients with inflammatory bowel disease compared with controls.

Objective: To assess body hydration and the distribution of the body water compartments in defined populations of patients with inflammatory bowel disease (IBD) compared with those of matched healthy controls.Subjects: Fifty-two patients with IBD at time of diagnosis (20 patients with Crohn’s disease (CD-new) and 32 patients with ulcerative colitis (UC-new)), 40 patients with long-standing CD (CD-long) and 2 matched healthy control groups (n=52 and n=40) were recruited for the study.Methods: Total body water (TBW) and extracellular water (ECW) were measured by deuterium oxide and bromide dilution, respectively. Intracellular water (ICW) was calculated as TBW-ECW. In addition, hydration of fat-free mass (FFM) and the ECW:ICW ratio were calculated. FFM, body fat (BF) and % body fat (%BF) were assessed by dual energy X-ray absorptiometry.Results: In female IBD patients, the ECW:ICW ratio was significantly (P<0.05) higher than in controls (CD-new: 0.89±0.11 vs 0.79±0.08, P<0.01; UC-new: 0.85±0.15 vs 0.77±0.10, P<0.05; CD-long: 0.86±0.14 vs 0.80±0.10, P<0.05). In these female patients, the ICW:FFM ratio was significantly (P<0.05) lower than in controls. Fluid shifts were especially pronounced in female patients with recently diagnosed CD. In male patients with recently diagnosed UC and in those with long-standing CD, body weight, body mass index, BF and %BF were significantly (P<0.05) lower than in controls. No differences in body hydration or body water distribution were observed between male patients and controls.Conclusions: An altered body water distribution and body hydration was observed in female IBD patients, especially in female patients with recently diagnosed CD.Sponsorship: This study was financially supported by a grant from Novartis Nutrition Ltd, Switzerland.

Energy expenditure and physical activity in relation to bone mineral density in women with anorexia nervosa

Objectives: To assess sleeping metabolic rate (SMR), average daily metabolic rate (ADMR), and total bone mineral density (TBMD) in women with anorexia nervosa, and to evaluate the effect of daily physical activity on TBMD.Design: We compared women with anorexia nervosa and controls using measurements on body composition, and energy expenditure. Relations between these measurements were investigated.Setting: Daily living environments in The Netherlands, and body composition and energy expenditure laboratory of the Department of Human Biology.Subjects: Twelve adult, non-hospitalized women with anorexia nervosa, and sixteen adult normal weight women.Interventions: Average daily metabolic rate was measured with the doubly labeled water method and sleeping metabolic rate in a respiration chamber. TBMD was measured by dual energy X-ray absorptiometry, and percentage body fat was calculated combining the results from underwater weighing and deuterium dilution.Results: TBMD was significantly lower in anorexia than in controls (0.989±0.081 vs 1.144±0.054 g/cm2). Also ADMR and SMR were reduced in anorexia. The physical activity index (PAI=ADMR/SMR) was not significantly different from PAI in controls. In anorexia, TBMD was related to the PAI (R2=0.35, P< 0.05). Finally, stepwise multiple regression revealed that PAI together with the study groups as dummy variables could explain 69% of the variation in TBMD.Conclusion: These findings show that in anorexia TBMD is reduced, but that nonetheless physical activity has a significant positive effect on bone density.

Amenorrhea in ballet dancers in the Netherlands.

The prevalence of amenorrhea was studied among 113 professional and student ballet dancers in the Netherlands (mean age 23.3 yr, SD 4.8). Sixty-one dancers not on oral contraceptives were included in the subsequent analyses. Six cases (prevalence 9.8 percent, 95 percent confidence interval: 2.4-17.2) with secondary amenorrhea (< or = 4 cycles per year; previous menstruation > or = 3 months prior to the study; menarche > or = 1 yr prior to the study) were found. Two dancers had primary amenorrhea (no menarche at the age of > or = 16). There was a negative correlation between the age of menarche and the number of menstrual cycles during the 12 months preceding the study (r = -0.46, P = 0.001). Body composition (four-compartment model), amount of dancing (recorded), resting energy expenditure (ventilated hood), dietary intake (recorded), and indices of eating disorders (Eating Disorders Inventory, EDI) were studied in 15 of the dancers, 5 amenorrheic and 10 eumenorrheic. No significant differences were found between the amenorrheic and eumenorrheic dancers. An explanation for the lower prevalence of amenorrhea in ballet dancers in the Netherlands, compared with U.S. dancers, was not obvious. Relatively low EDI scores (25.8, SD 14.5) in a subsample of 24 dancers could indicate less rigid emphasis on leanness and dieting.