Interpretation of Dual-Energy X-Ray Absorptiometry-Derived Body Composition Change in Athletes: A Review and Recommendations for Best Practice

Abstract

Dual-energy X-ray absorptiometry (DXA) is a medical imaging device which has become the method of choice for the measurement of body composition in athletes. The objectives of this review were to evaluate published longitudinal DXA body composition studies in athletic populations for interpretation of "meaningful" change, and to propose a best practice measurement protocol. An online search of PubMed and CINAHL via EBSCO Host and Web of Science enabled the identification of studies published until November 2016. Those that met the inclusion criteria were reviewed independently by 2 authors according to their methodological quality and interpretation of body composition change. Twenty-five studies published between 1996 and November 2016 were reviewed (male athletes: 13, female athletes: 3, mixed: 9) and sample sizes ranged from n = 1 to 212. The same number of eligible studies was published between 2013 and 2016, as over the 16 yr prior (between 1996 and 2012). Seven did not include precision error, and fewer than half provided athlete-specific precision error. There were shortfalls in the sample sizes on which precision estimates were based and inconsistencies in the level of pre-scan standardization, with some reporting full standardization protocols and others reporting only single (e.g., overnight fast) or no control measures. There is a need for standardized practice and reporting in athletic populations for the longitudinal measurement of body composition using DXA. Based on this review and those of others, plus the official position of the International Society for Clinical Densitometry, our recommendations and protocol are proposed as a guide to support best practice.

Same-Day Vs Consecutive-Day Precision Error of Dual-Energy X-Ray Absorptiometry for Interpreting Body Composition Change in Resistance-Trained Athletes

“…Nevertheless, it should be noted that the consecutive-day precision errors in the current study were within the acceptable limits for DXA precision as identified by the ISCD which are 3% for FM and 2% for LM [7]. Further, the precision error values were similar to those found in a number of studies as recently reviewed [8].…”

“…The ability to confidently quantify these small but potentially important changes in body composition can enable better refinement of interventions, and thus, potentially enhance athletic performance. The International Society for Clinical Densitometry (ISCD) recommends the application of the least significant change (LSC) in the interpretation of longitudinal body composition measurements, which is calculated using sameday repeat scans [7,8]. LSC quantifies precision based on two consecutive scans, thus identifying the technical error inbuilt into a specific piece of equipment for a given population [7].…”

Relationship between Knee Muscle Strength and Fat/Muscle Mass in Elderly Women with Knee Osteoarthritis Based on Dual-Energy X-Ray Absorptiometry

“…The scale comprises 24 questions: 5 questions on pain evaluation, 2 questions on joint stiffness, and 17 questions on physical function [19]. The WOMAC scale has been widely used to evaluate hip and knee joint dysfunction and is a standard questionnaire for evaluating pain, joint stiffness, and dysfunction amongst patients with osteoarthritis [20]. A high score on the WOMAC index indicates severe OA.…”

“…This method is widely used on account of its low cost, simple operation, and reliable results. A recent systematic review showed that DXA could be regarded as a new gold standard for measuring the body composition because it is highly correlated with nuclear magnetic resonance and computed X-ray tomography [20]. Up until now, DXA has been used to measure the bone mineral density and the body composition of athletes, thus providing a suitable reference for the training and diet plan [20].…”

Total body skeletal muscle mass estimated by magnetic resonance imaging and creatine (methyl‐d3) dilution in athletes

“…The current imaging gold standard, magnetic resonance imaging (MRI), allows for objective, and accurate measures of muscle mass, but is expensive and its availability is limited, while alternative techniques, such as bioelectrical impedance analysis and air displacement plethysmography, lack precision . Dual x‐ray absorptiometry (DXA) has become increasingly prolific within elite and professional sport environments, and the reliability of the method in athletic populations has improved, but DXA does not measure muscle mass per se, but rather lean tissue mass.…”