Body composition, as assessed by bioelectrical impedance spectroscopy and dual-energy X-ray absorptiometry, in a healthy paediatric population

Comparison of Dual-Energy X-ray Absorptiometry and Bioelectrical Impedance Analysis in the Assessment of Body Composition in Women with Anorexia Nervosa upon Admission and Discharge from an Inpatient Specialist Unit

Assessment of body composition is fundamental in diagnosis and treatment of anorexia nervosa (AN). The gold standard dual-energy X-ray absorptiometry (DXA) is expensive and not universally available. Bioelectrical impedance analysis (BIA) is a non-invasive, inexpensive method relative to DXA. We compared DXA and BIA in the assessment of fat-free mass (FFM), fat mass (FM), and body fat percentage (BF%) in women with AN upon admission (ANT1) and discharge (ANT2) from an inpatient specialist unit with a referent healthy control (HC) group. The study population consisted of 31 ANT1, 25 ANT2, and 52 HC women with median age of 21 years. Body composition was measured by DXA and Tanita foot-to-foot BIA. Comparison between the two methods was done using Bland–Altman analysis, Pearson’s correlation coefficient, Lin’s concordance correlation coefficient, and linear regression. The mean difference (bias) in FM and BF% values obtained by DXA and BIA in ANT1 (FM: +1.01 kg, BF%: +2.26%) and ANT2 (FM: +1.49 kg, BF%: +1.66%) were comparable to HC (FM: −1.32 kg, BF%: −2.29%) although in opposite directions. Less bias was observed in FFM values in ANT1 (−0.46 kg) and ANT2 (−0.86 kg) than in HC (+2.03 kg); however, the limits of agreement between the two methods were wider in ANT1 and ANT2 than in HC for all measurements. No association was observed between age, percentage of total body water, and the time spent on the inpatient specialist unit with the difference in estimates of body composition between DXA and BIA. Comparison of DXA and BIA suggests that DXA should remain the gold standard for measuring body composition; the development of more specific BIA equations is required to improve validity and precision of BIA in patients with AN. Despite ease and cost in both BIA access and operation, the suitability of BIA in a low bodyweight eating disorders population remains questionable.

Effect of regional muscle damage and inflammation following eccentric exercise on electrical resistance and the body composition assessment using bioimpedance spectroscopy

We investigated the effect of muscle damage and inflammation on electrical resistance and the body composition assessment by using bioimpedance spectroscopy (BIS). Twenty-two subjects completed 30 repetitions of maximal eccentric contractions of the elbow flexors with one arm. Whole-body resistance of extracellular and intracellular components (Re and Ri, respectively) on the exercised and non-exercised sides were measured using BIS. Body composition was calculated from both sides of resistance at baseline and 96 h after exercise. Re decreased only on the exercised side at 96 h after exercise (P < 0.05). Fat-free and fat mass values estimated from resistance on the exercised side were altered by 3.1% and - 15.6%, respectively, at 96 h after exercise (P < 0.05); those estimated from the non-exercised side were unaltered. Eccentric exercise-induced muscle damage and inflammation reduce Re and induce non-negligible estimation error in the body composition assessment using BIS.

Relationship between the muscle relaxation effect and body muscle mass measured using bioelectrical impedance analysis: A nonrandomized controlled trial

Objective

The dose of neuromuscular blocking drugs is commonly based on body weight, but using muscle mass might be more effective. This study investigated the relationship between the effect of neuromuscular blocking drugs and muscle mass measured using bioelectrical impedance analysis.

Methods

Patients who were scheduled for elective surgery using a muscle relaxant were screened for inclusion in this study. Under intravenous anaesthesia, 12 mg or 9 mg of rocuronium was administered to males and females, respectively; and the maximal relaxation effect of T1 was measured using a TOF-Watch-SX® acceleromyograph.

Results

This study enrolled 40 patients; 20 males and 20 females. For both sexes, the maximal relaxation effect of T1 did not correlate with the body weight-based dose of neuromuscular blocking drugs (males, r² = 0.12; females, r² = 0.26). Instead, it correlated with the dose based on bioelectrical impedance analysis-measured muscle mass when injected with the same dose of rocuronium (males, r² = 0.78, female, r² = 0.82).

Conclusions

This study showed that the muscle relaxation effect of rocuronium was correlated with muscle mass and did not correlate with body weight when using the same dose. Therefore, a muscle mass-based dose of neuromuscular blocking drugs is recommended.

Body mass but not vitamin D status is associated with bone mineral content and density in young school children in northern Sweden

Background

High latitude of residence where sun exposure is limited affects vitamin D status. Although vitamin D levels have been associated with poor bone health, cut-off values for optimising bone health are yet to be decided.

Objective

To assess vitamin D intake and status among young school children living at latitude 63–64 °N, in northern Sweden and to examine the association between vitamin D status and bone mineral content (BMC) and bone mineral density (BMD).

Design

In a cross-sectional study, diet was assessed by a 4-day food diary and a food frequency questionnaire in 8- to 9-year-old children (n=120). Energy, vitamin D, and calcium intakes were calculated. Physical activity was assessed using a pedometer for 7 days. Serum 25-hydroxyvitamin D (S-25[OH]D) levels were analysed by high-pressure liquid chromatography-atmospheric pressure chemical ionisation-mass spectrometry (n=113). BMC and BMD were assessed by dual energy X-ray absorptiometry scan. Height and weight were measured by standard procedures and BMI z-score was calculated using WHO AnthroPlus programme.

Results

The majority of children, 91%, did not reach the recommended vitamin D intake of 7.5 µg/day and 50% had insufficient S-25[OH]D levels defined as <50 nmol/l. The highest concentrations of S-25[OH]D were observed during the summer months (p=0.01). Body mass (p<0.01) but not S-25[OH]D was associated with measures of BMC and BMD. Furthermore, boys had higher total BMC (p=0.01), total body less head BMC (p=0.02), fat free mass (p<0.01), and a higher degree of physical activity (p=0.01) compared to girls.

Conclusions

Body mass was related to BMC and BMD measures in a population of prepubertal school children living at high latitudes in Sweden. Despite insufficient S-25[OH]D levels and low vitamin D intake, this did not appear to affect bone parameters. Prospective studies with repeated assessment of vitamin D status are needed to examine cut-off values for optimising bone health.

Validity of Four Commercial Bioelectrical Impedance Scales in Measuring Body Fat among Chinese Children and Adolescents

The aim of the study is to examine the validity in predicting body fat percentage (%BF) of different bioelectrical impedance (BIA) devices among Chinese children and adolescents. A total of 255 Chinese children and adolescents aged 9-19 years old participated in the study. %BF was assessed by BIA scales, namely, Biodynamics-310 (Model A), Tanita TBF-543 (Model B), Tanita BC-545 (Model C), and InBody 520 (Model D). Dual-energy X-ray absorptiometry (DXA) was used as the criterion measurement. Lin's concordance correlation coefficients of estimated %BF between Model A, Model B, Model C, and DXA showed poor agreements for both genders. Moderate agreements for %BF were found between DXA and Model D measurements. In boys, differences in %BF were found between DXA and Model B and Model C. No significant %BF differences were found between Model A, Model D, and DXA. However, the two BIA analyzers showed a significant positive correlation between the bias and average %BF between BIA and DXA. In girls, differences in %BF were observed between Model B, Model C, Model D, and DXA. Model A and DXA showed no significant differences of %BF; however, the bias and the average %BF between the BIA and DXA had a significant positive correlation. Using embedded equations in BIA devices should be validated in assessing the %BF of Chinese children and adolescents.

Predicting body composition using foot-to-foot bioelectrical impedance analysis in healthy Asian individuals

Background

The objectives of this study were to develop a regression model for predicting fat-free mass (FFM) in a population of healthy Taiwanese individuals using standing foot-to-foot bioelectrical impedance analysis (BIA) and to test the model’s performance in predicting FFM with different body fat percentages (BF%).

Methods

We used dual-energy X-ray absorptiometry (DXA) to measure the FFM of 554 healthy Asian subjects (age, 16–75 y; body mass index, 15.8–43.1 kg/m²). We also evaluated the validity of the developed multivariate model using a double cross-validation technique and assessed the accuracy of the model in an all-subjects sample and subgroup samples with different body fat levels.

Results

Predictors in the all-subjects multivariate model included height²/impedance, weight, year, and sex (FFM = 13.055 + 0.204 weight + 0.394 height²/Impedance – 0.136 age + 8.125 sex (sex: Female = 0, Male = 1), r² = 0.92, standard error of the estimate = 3.17 kg). The correlation coefficients between predictive FFM by BIA (FFM_BIA) and DXA-measured FFM (FFM_DXA) in female subjects with a total-subjects BF%_DXA of <20 %, 20 %–30 %, 30 %–40 % and >40 % were r = 0.87, 0.90, 0.91, 0.89, and 0.94, respectively, with bias ± 2SD of 0.0 ± 3.0 kg, −2.6 ± 1.7 kg, −1.5 ± 2.8 kg, 0.5 ± 2.7 kg, and 2.0 ± 2.9 kg, respectively. The correlation coefficients between FFM_BIA and FFM_DXA in male subjects with a total-subjects BF%_DXA of <10 %, 10 %–20 %, 20 %–30 %, and >30 % were r = 0.89, 0.89, 0.90, 0.93, and 0.91, respectively, with bias ± 2SD of 0.0 ± 3.2 kg, −2.3 ± 2.5 kg, −0.5 ± 3.2 kg, 0.4 ± 3.1 kg, and 2.1 ± 3.2 kg, respectively.

Conclusions

The standing foot-to-foot BIA method developed in this study can accurately predict FFM in healthy Asian individuals with different levels of body fat.

Probiotics during weaning: a follow-up study on effects on body composition and metabolic markers at school age

PURPOSE

An aberrant gut microbiome has been suggested to contribute to the worldwide epidemic of obesity. In animal models, the probiotic Lactobacillus paracasei ssp. paracasei F19 (LF19) induced upregulation of genes involved in energy homoeostasis, reduced body fat and altered the serum (S) lipoprotein profile. In our previous report, feeding LF19 to infants during weaning impacted the global plasma metabolome. LF19 lowered palmitoleic acid, a monounsaturated fatty acid associated with hypertriglyceridemia and increased visceral adiposity. Therefore, we assessed if feeding LF19 from 4 to 13 months of age would have long-term effects on body composition, growth and metabolic markers.

METHODS

Of 179 children included in our baseline study, 120 entered the follow-up at 8-9 years of age, n = 58 in the probiotic and n = 62 in the placebo group. Body composition was measured using dual energy X-ray absorptiometry. Anthropometrics of the child and accompanying parent(s) were assessed. S-lipids, insulin, glucose and transaminases were determined after overnight fasting.

RESULTS

LF19 did not affect body mass index z-score, sagittal abdominal diameter, fat-free mass, fat mass index, truncal fat %, android or gynoid fat % and had no long-term impact on any of the assessed metabolic markers (p > 0.05).

CONCLUSION

Feeding LF19 during infancy did not modulate body composition, growth or any of the assessed metabolic markers at school age. The steady increase in probiotic products targeting infants and children calls for long-term follow-up of initiated probiotic intervention studies.

Ethnic variation in body composition assessment in a sample of adolescent girls

OBJECTIVE

To compare body composition assessment by bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) in a multiethnic sample of adolescent girls.

METHOD

Data were from a physical activity intervention study among 254 14-20-year-old sedentary American girls, including 69 whites, 74 blacks, 42 Hispanics, and 69 Asians. Height and weight were objectively measured. Body composition was assessed using a foot-to-foot BIA and a fan-beam DXA. We calculated ethnic-specific estimates of percentage body fat (BF%), fat mass (FM), fat mass index (FMI), fat-free mass (FFM), and fat-free mass index (FFMI) from BIA and DXA. We used Bland-Altman plots to examine ethnic-specific agreement between BIA and DXA, and used linear regression to test whether the BIA-DXA difference varied across the mean.

RESULTS

Compared to DXA, BIA estimates of fat measures (BF%, FM, and FMI) were lower and lean tissue measures (FFM and FFMI) higher. For example, the BIA-estimated BF% was lower than the DXA estimate by between 4.9% (95% CI: -5.9, -3.9) in blacks and 8.7% (-7.0, -5.0) in Asians, with large limits of agreement (-15.4 to -5.4 in blacks and -16.8 to -0.4 in Asians). Regression analysis showed that BIA-DXA differences were not constant across means for any body composition measure among Asians or for any measure except BF% among whites.

CONCLUSION

Compared to DXA, BIA yielded lower estimates of adiposity in a multiethnic adolescent sample. BIA-DXA differences varied by ethnicity, and across mean body composition values for some ethnicities.

Relationship between body mass index and adiposity in prepubertal children: ethnic and geographic comparisons between New York City and Jinan City (China)

Body mass index (BMI) is often used as a surrogate estimate of percent body fat in epidemiological studies. This study tested the hypothesis that BMI is representative of body fatness independent of age, sex, ethnicity, and geographic location in prepubertal children. The study sample included a total of 605 prepubertal children (275 girls and 330 boys) of which 247 were Chinese from Jinan, Shandong, Mainland China, and 358 children were from various ethnic backgrounds in New York City (NYC): 121 Caucasians, 94 African Americans, and 143 Asians (Chinese and Korean). In this cross-sectional study, dual energy X-ray absorptiometry was used to quantify total body fat (TBF) and percent body fat (PBF). Prepubertal status was assessed by the criteria of Tanner. Multiple regression models were developed with TBF and PBF as the dependent variables and BMI, age, sex, and ethnicity as independent variables. Multiple regression analysis showed that BMI alone explained 85% and 69% of between-subject variance for TBF and PBF, respectively. Sex was a significant contributor to the models (P<0.001) with girls having higher TBF and PBF than boys. Ethnicity and geographic location were significant contributors to the model (P<0.0001) with Asians (Jinan and NYC Asians) having higher PBF than all non-Asian groups (P<0.0001), and Jinan Asians having higher TBF and PBF than NYC-Asians. Among prepubertal children, for the same BMI, Asians have significantly higher PBF compared with African Americans and Caucasians. Caution is warranted when applying BMI across sex and ethnic prepubertal groups.

Precision and reliability of strength (Jamar vs. Biodex handgrip) and body composition (dual-energy X-ray absorptiometry vs. bioimpedance analysis) measurements in advanced cancer patients

Important deteriorations in body composition and strength occur and need to be accurately measured in advanced cancer patients (ACPs). The aim of this study was to establish the relationship between a single-frequency bioimpedance analyzer (BIA) and the dual-energy X-ray absorptiometer (DXA), as well as the Jamar handgrip dynometer and the Biodex handgrip attachment, and to determine the precision of each of these instruments in ACPs. Eighty-one ACPs with non-small-cell lung cancer and gastrointestinal cancer were recruited from the McGill University Health Centre (Montreal, Que.). Consecutive paired measurements, with repositioning between measurements, were obtained for total-body DXA, BIA, Biodex handgrip, and BIA plus Jamar handgrip. The total-body percent coefficient of variation (%CV) for the BIA and DXA were 1.34 and 1.56 for fat mass (FM), respectively, and 0.42 and 0.72 for fat free mass (FFM), respectively. The %CV for the Jamar and Biodex handgrips were 6.3 and 16.7, respectively. Bland–Altman plots were used to characterize the limits of agreement between DXA and BIA for FM (4.60 ± 7.80 (–3.19 to 12.39) kg) and FFM (–1.87 ± 7.16 (–9.03 to 5.29) kg). Both DXA and BIA demonstrate good short-term precision in ACPs. However, given its poor accuracy, it remains to be determined if BIA can be used to monitor ACPs for changes in total-body tissue composition as a function of time, whether for observation or response to treatment. Furthermore, because of wide limits of agreement, the DXA and BIA cannot be used interchangeably in research or clinical settings. The Jamar handgrip dynamometer shows more consistency than the Biodex handgrip attachment in ACPs, and should therefore be the preferred measure of changes in strength over time.

BMI and objectively measured body fat and body fat distribution in prepubertal children

BACKGROUND

Body Mass Index (BMI) is often used as a surrogate estimate of body fat in epidemiological studies. This study explores the association between BMI, body fat and body fat distribution assessed by Dual-Energy X-Ray Absorptiometry (DXA) in younger children.

METHODS

Cross-sectional study of 246 children (138 boys and 108 girls) aged 8-11 years. DXA was used to quantify abdominal fat mass (AFM), total body fat (TBF) and also total body fat as percentage of total body mass (BF%). Body fat distribution was calculated as AFM/TBF.

RESULTS

We found close correlations between BMI vs. TBF, BF% and AFM (r = 0.94, r = 0.92 and r = 0.93) for boys and (r = 0.95, r = 0.92 and r = 0.95) for girls, respectively (P<0.05 for all r-values). However, significantly lower correlation (P<0.001 for difference between the r-values) existed for body fat distribution (r = 0.64 for boys and 0.73 for girls).

CONCLUSION

Percentage body fat, TBF and AFM were all closely associated with BMI, suggesting that BMI serves as a good surrogate marker for obesity in population studies. However, a significantly lower correlation existed for BMI vs. body fat distribution, which may be a limitation when BMI is used to study cardiovascular risk factors in epidemiological studies.