Whole-body dual-energy X-ray absorptiometry demonstrates better reliability than segmental body composition analysis in college-aged students

Abstract

Dual-energy X-ray absorptiometry (DXA) is rapidly becoming more accessible and popular as a technique to monitor body composition. The reliability of DXA has been examined extensively using a number of different methodological approaches. This study sets up to investigate the accuracy of measuring the parameters of body composition (BC) by means of the whole-body and the segmental DXA method analysis with the typical error of measurement (TEM) that allows for expressing the error in the units of measure. The research was implemented in a group of 63 participants, all of whom were university students. Thirty-eight males (22.6±2.9 years, average body mass 77.5±8.4 kg) and 25 females (21.4±2.0 years, average body mass 58.6±7.2 kg) were recruited. The measured parameters included body mass (BM), fat-free mass (FFM), body fat (BF), bone mineral content (BMC), bone mineral density (BMD). For the whole-body analysis, the determined TEM was: BM at the level of 0.12 kg in females and 0.29 kg in males; BF 0.25kg and 0.44% females, 0.52 kg and 0.66% males; FFM 0.24 kg females and 0.42 kg males; BMC 0.02 kg females and males; BMD 0.01g/cm 2 females and males. The TEM values in the segmental analysis were: BF within the range of 0.04–0.28 kg and 0.68–1.20% in females, 0.10–0.36 kg and 0.72–1.94% in males; FFM 0.08–0.41 kg females and 0.17–0.86 males, BMC 0.00–0.02 kg females and 0.01–0.02 kg males in relation to the body segment (upper limb, trunk, lower limb). The BMD value was at the level of 0.01–0.02g/cm 2 . The study results showed high reliability in measuring body composition parameters using the DXA method. The whole-body analysis showed a higher accuracy of measurement than the segmental. Only the changes that are greater than the TEM, or the upper bound (95%) of the confidence interval of the measurement can be considered demonstrable when interpreting repeated measurements.

Indicators of Sarcopenia: Sex Differences in Competitive Runners Prior to Peak Muscle Mass

“…Collectively, runners demonstrated a 2.4 % increase over one year in total body BFLM compared to a 0.8 % increase in non-runners and whole-body BFLM was higher in both male and female runners compared to their non-running counterparts, but these differences were not due to differences in the upper-extremity. The likelihood that this represents real change is supported in the finding that these changes in BFLM ( > 1 kg) fall well above published whole body scan-rescan precision assessments observed in similarly sized, collegiate males (typical error of measurement (TEM) = 0.42 kg, 95 % CI = 0.36-0.50 kg) and females (TEM = 0.24 kg, 95 % CI = 0.20-0.30 kg) using the same type of DXA scanner [25]. These findings suggest that benefits in sarcopenia prevention due to competitive running are masked when examining handgrip strength, the most common upper-body index of muscular performance alone.…”

“…Similarly, Hart et al (2015) reported intra-tester CVs of 1.6-1.9 % and inter-tester CVs of 1.8-2.2 % for a variety of upper extremity lean mass values in professional athletes while using the same DXA model. Lastly, Kutac et al [25], again using the same DXA model to investigate retest precision of segmental analyses of lean mass, revealed nearly perfect correlational reliability and error approximations in male (TEM = 0.17 kg, 95 % CI = 0.14-0.20 kg) and female (TEM = 0.08 kg, 95 % CI = 0.07-0.10 kg college students. These studies collectively demonstrate a robust precision of whole body and segmental lean mass assessments when technicians tightly adhere to positioning procedures.…”

“…Both measures, taken without shoes and in minimal clothing were then used to calculate BMI as the body mass (kg) divided by height (m) squared. Following positioning procedures for whole-body scans resulting in scan-rescan coefficients of variation for body composition variables of less than 1 % [25], whole body scans were performed on all participants using dual-energy x-ray absorptiometry (DXA; Hologic Discovery A, Waltham, MA) with all analyses performed on Hologic Apex version 4.5 software. DXA scan results provided bone-free lean mass (BFLM), fat mass, and percent body fat for both the whole body and segmental analysis for each of the arms.…”

Concurrent validity of five prediction equations to evaluate fat percentage in a sports group expected to yield high performance from Medellín, Colombia

“…Body composition and the changes it undergoes play an important role in athletes’ performance, particularly in those who are in the process of physical development as their physical abilities directly affect their performance and the risk of injuries when practicing sports modalities based on resistance, strength, power, or speed ( 1 - 4 ). It is vital, then, to count with evaluation methods of proven validity and reliability ( 3 - 5 ).…”

“…The personnel in charge of athletes who are still developing their abilities or those that are already professionals use doubly indirect methods to measure the body composition: the data derived from measuring skin folds and the information from bioimpedance devices later used to feed prediction formulas specifically adjusted to the population for whom they were developed that may not necessarily be applicable elsewhere, as is the case of athletes from Medellín expected to become high performers ( 1 , 2 , 4 ).…”