Which method to use for a fast assessment of body fat percentage?

Direct Comparison of (Anthropometric) Methods for the Assessment of Body Composition

OBJECTIVE

Several methods for the assessment of body composition exist, yet they yield different results. The present study aimed to assess the extent of these differences on a sample of young, healthy subjects. We hypothesised that differences in body composition results obtained with different methods will vary to the extent that a subject can be misclassified into different nutritional categories.

RESEARCH METHODS AND PROCEDURES

Underwater weighing (UWW), bioelectrical impedance analysis (BIA), anthropometry (ANT), and dual-energy X-ray absorptiometry (DXA) were used to assess body composition. An extensive list of ANT regression equations (or sets of equations) was analysed in terms of accuracy and precision relative to DXA.

RESULTS

When DXA-determined body fat (BF) values were taken as a reference, UWW overestimated BF in both genders. In contrast, BIA (measured with a given bioimpedance analyser) underestimated BF in females, although BIA-determined BF did not differ from DXA in males. A huge difference in BF estimates (8-29% for females and 6-29% for males, for DXA-determined BF of 25.5% and 13.9% for females in males, respectively) was observed across a number of ANT regression equations; yet, ANT proved not to be inferior to DXA, provided that regression equations with the highest combinations of accuracy and precision were chosen.

CONCLUSIONS

The study proved grounds for comparison of body composition results of young, healthy subjects, obtained with different methods and across a wide range of ANT regression equations. It also revealed a list of the most appropriate ANT regression equations for the selected sample and reported their accuracy and precision.

Body composition in Spinocerebellar ataxia type 3 and 10 patients: Comparative study with control group

Background: Spinocerebellar ataxias (SCAs) are a group of neurodegenerative genetic diseases characterized by movement disorders that can affect nutritional status and body composition. This study sought to assess body composition in SCA3 and SCA10 patients. Methods: Anthropometric assessments and bioelectric impedance analysis were performed in 46 SCA3 and SCA10 patients and 76 controls of both genders. Results: Of the patients, 69.6% had SCA3 and 58.7% were women. SCA3 patients had significantly lower percentages of body fat (%BF) than controls (15.0 ± 6.1 vs. 20.6 ± 7.1; p=0.014) and (22.4 ± 6.9 vs. 30.1 ± 6.0; p<0.001), respectively. Among the women, there was a statistically significant difference in %BF between SCA3 and SCA10 patients (22.4 ± 6.9 vs. 32.4 ± 4.9; p<0.001). Male and female SCA3 patients had significantly lower fat-free mass (FFM) than controls [50.6 kg (46.9-54.7) vs. 58.6 kg (52.6-63.9); p=0.001] and [38.2 kg (35.1-42.6) vs. 42.8 kg (39.7-46.1); p=0.004], respectively. Male SCA10 patients also had lower FFM than controls [51.2 kg (47.1-55.4) vs. (52.6-63.9); p=0.008]. Female SCA10 patients had significantly higher FFM than controls and SCA3 patients [45.0 kg (43.3-45.6) vs. 42.8 kg (39.7-46.1); p=0.004] and [45.0 kg (43.3-45.6) vs. 38.2 kg (35.1-42.6); p=0.004], respectively. There was moderate correlation (-0.42) between disease duration and muscle mass (MM), and weak (-0.38) between SARA (Scale for the Assessment and Rating of Ataxia) and MM in SCA3. In SCA10, there was no significant correlation between these variables. Conclusion: Female SCA3 patients had more body composition changes than female SCA10 patients, mainly in relation to FFM. SCA3 and SCA10 patients need nutritional follow-up to minimize body compartment changes.

Whole-body adipose tissue and lean muscle volumes and their distribution across gender and age: MR-derived normative values in a normal-weight Swiss population

PURPOSE

To determine age- and gender-dependent whole-body adipose tissue and muscle volumes in healthy Swiss volunteers in Dixon MRI in comparison with anthropometric and bioelectrical impedance (BIA) measurements.

METHODS

Fat-water-separated whole-body 3 Tesla MRI of 80 healthy volunteers (ages 20 to 62 years) with a body mass index (BMI) of 17.5 to 26.2 kg/m² (10 men, 10 women per decade). Age and gender-dependent volumes of total adipose tissue (TAT), visceral adipose tissue (VAT), total abdominal subcutaneous adipose tissue (ASAT) and total abdominal adipose tissue (TAAT), and the total lean muscle tissue (TLMT) normalized for body height were determined by semi-automatic segmentation, and correlated with anthropometric and BIA measurements as well as lifestyle parameters.

RESULTS

The TAT, ASAT, VAT, and TLMT indexes (TATi, ASATi, VATi, and TLMTi, respectively) (L/m²  ± standard deviation) for women/men were 6.4 ± 1.8/5.3 ± 1.7, 1.6 ± 0.7/1.2 ± 0.5, 0.4 ± 0.2/0.8 ± 0.5, and 5.6 ± 0.6/7.1 ± 0.7, respectively. The TATi correlated strongly with ASATi (r > 0.93), VATi, BMI and BIA (r > 0.70), and TAATi (r > 0.96), and weak with TLMTi for both genders (r > -0.34). The VAT was the only parameter showing an age dependency (r > 0.32). The BMI and BIA showed strong correlation with all MR-derived adipose tissue volumes. The TAT mass was estimated significantly lower from BIA than from MRI (both genders P < .001; mean bias -5 kg).

CONCLUSIONS

The reported gender-specific MRI-based adipose tissue and muscle volumes might serve as normative values. The estimation of adipose tissue volumes was significantly lower from anthropometric and BIA measurements than from MRI. Magn Reson Med 79:449-458, 2018. © 2017 International Society for Magnetic Resonance in Medicine.