Comparing measures of fat-free mass in overweight older adults using three different bioelectrical impedance devices and three prediction equations

Validity of Body-Composition Methods across Racial and Ethnic Populations

Multi-compartment body-composition models that divide the body into its multiple constituents are the criterion method for measuring body fat percentage, fat mass, and fat-free mass. However, 2- and 3-compartment body-composition devices such as air displacement plethysmography (ADP), DXA, and bioelectrical impedance devices [bioelectrical impedance analysis (BIA)] are more commonly used. Accurate measures depend on several assumptions, including constant hydration, body proportion, fat-free body density, and population characteristics. Investigations evaluating body composition in racial and ethnic minorities have observed differences in the aforementioned components between cohorts. Consequently, for racial/ethnic minority populations, estimates of body composition may not be valid. The purpose of this review was to comprehensively examine the validity of common body-composition devices in multi-ethnic samples (samples including >1 race/ethnicity) and in African-American, Hispanic, Asian, and Native American populations. Based on the literature, DXA produces valid results in multi-ethnic samples and ADP is valid for Hispanic and African American males when utilizing race-specific equations. However, for DXA and ADP, there is a need for validity investigations that include larger, more racially diverse samples, specifically including Hispanic/Latinx, Asian, Native American adults, and African-American females. Technology has advanced significantly since initial validity studies were conducted; therefore, conclusions are based on outdated models and software. For BIA, body-composition measures may be valid in a multi-ethnic sample, but the literature demonstrates disparate results between races/ethnicities. For BIA and ADP, the majority of studies have utilized DXA or hydrostatic weighing as the criterion to determine validity; additional studies utilizing a multi-compartment model criterion are essential to evaluate accuracy. Validity studies evaluating more recent technology in larger, more racially/ethnically diverse samples may improve our ability to select the appropriate method to accurately assess body composition in each racial/ethnic population.

A multidisciplinary team-based approach with lifestyle modification and symptom management to address the impact of androgen deprivation therapy in prostate cancer: A randomized phase II study

BACKGROUND

Androgen deprivation therapy (ADT) is associated with numerous toxicities that are potentially modifiable. We sought to evaluate the impact of participation in a multidisciplinary clinic, STAND (Supportive Therapy in Androgen Deprivation) Clinic, designed to provide individualized lifestyle modification and management of ADT-related side effects.

METHODS

This phase II study recruited men with prostate cancer who had started ADT <6 months prior to enrollment, and in whom ADT was planned for at least 12 months following enrollment. Patients were randomized in a 1:1 ratio to either the STAND Clinic or usual care. Patients randomized to the STAND Clinic were provided monthly multidisciplinary assessment and counseling on exercise, nutrition, and symptom management for 12 months on a rotating schedule. Primary outcome was change from baseline to 12 months in percent body fat. Feasibility outcomes were also assessed by measuring percentage of completed visits. Secondary outcomes included change from baseline to 12 months in 3 domains: (1) metabolic impact and bone health, (2) quality of life (QOL), and (3) physical activity.

RESULTS

A total of 25 men were randomized to STAND clinic, and 23 were randomized to usual care. The study did not meet its accrual target of 32 men in each arm and was closed early due to lack of financial support. Overall, 91% (295 of 325) of STAND clinic visits were completed. Eighteen out of the 25 patients in STAND clinic arm (72%) completed all 12 months of STAND clinic visits, and 80% (20 of 25) completed the first 6 months. For all primary and secondary outcomes, there were no statistically significant differences between treatment arms.

CONCLUSION

Individualized and comprehensive management of ADT toxicities in a multidisciplinary clinic was well attended by patients. However, we did not find any differences in the outcomes assessed between the intervention arm and control.

Reproducibility and validity of A-mode ultrasound for body composition measurement and classification in overweight and obese men and women

Identifying portable methods to measure body composition may be more advantageous than using body mass index (BMI) to categorize associated health consequences. Purpose: To compare the validity and reliability of a portable A-mode ultrasound (US) to a criterion three compartment model (3C) for the measurement of body composition. Methods: Forty-seven overweight and obese subjects participated in this study. Body composition was measured once via air displacement plethysmography for body density (Bd) and bioelectrical impedance spectroscopy for total body water (TBW) for the 3C calculations. Ultrasound measurements (BodyMetrix, Intelametrix) were made using an A mode, 2.5- MHz transmitter. All measurements were made on the right side of the body at 7 skinfold sites. The US software calculated percent body fat (%BF), fat mass (FM) and fat free mass (FFM) from the 7-site Jackson and Pollock equation. Results: %BF and FM, respectively, measured by the US (29.1±6.5%; 27.4±8.1 kg) was significantly lower compared to the 3C model (33.7±7.6%; 31.8±9.8 kg; p<0.0005). Fat free mass was significantly higher for the US (66.7±13.0 kg) compared to the 3C model (62.3±12.6; p = 0.001). The US demonstrated respectable reliability for %BF, FM, and FFM with intraclass correlation coefficients (ICC) ranging from 0.84–0.98 and standard error of the measurement (SEM) values and 2.2%BF, 1.9 kg, 1.9 kg, respectively. Discussion: The US was found to under predict %BF and FM with large deviations from the criterion (n = 10>4%BF error). While the US was not valid in this population, it was reliable producing results with minimal error, suggesting this technique may be effective for tracking changes in a weight loss or clinical setting.

Precision of total and regional body fat estimates from dual-energy X-ray absorptiometer measurements

OBJECTIVES

To evaluate the precision of both total %fat and all the regional %fat measures acquired from both the Lunar Prodigy and Lunar iDXA software.

DESIGN

Cross-sectional study.

SETTING

University-based research laboratory.

PARTICIPANTS

The sample consisted of 300 individual test records from men and women who had volunteered to participate in dual-energy x-ray absorptiometer (DXA) technician precision training studies. Subjects ranged in age from 20-84 years and in body mass index from 15.7-52.0 kg.m-2.

MEASUREMENTS

A total of 27 different technicians performed three total body scan measurements on 10-15 different subjects. The Lunar Prodigy and Lunar iDXA were used for 253 and 47 precision training evaluations, respectively. The regions of interest (ROI) were automatically determined by the enCORE software (autoROI) for total body, android, gynoid, trunk, legs, and arms regions and the region %fat data were used for analyses.

RESULTS

The CV for total body %fat was 1.9% and 0.9% for the Prodigy and iDXA, respectively. CV's for %fat measures at regional sites ranged from 1.2-4.4% for the Prodigy measures and 0.9-2.4% for the iDXA measures. The ICC for both devices ranged from 0.990 to 0.999.

CONCLUSION

Monitoring the status of body composition changes with age is gaining more clinical acceptance. Thus, it is important that practitioners use measures that are both precise and accurate. The findings from the current study add support that DXA measurements can be used with a high level of confidence for serial testing of patients.