Use of Dual-Energy X-ray Absorptiometry for Body Composition in Chronic Disease Management

Abstract

Aging and chronic disease are often accompanied by changes in body composition that lead to decreased muscle mass and increased fat mass, even in weight-stable individuals. Both obesity and sarcopenia are important causes of frailty, disability, morbidity, and mortality. Diminished skeletal muscle and expanded visceral fat can act synergistically, which might maximize their effects on physical impairments and metabolic disorders. Dual-energy X-ray absorptiometry (DEXA) was regarded as one of the most versatile imaging techniques for evaluation of sarcopenia and obesity as well as osteoporosis. Whole-body DEXA allows total and regional assessment of the three compartments for fat mass, non-bone lean mass, and bone mineral content. Moreover, DEXA is accurate, reproducible, fast, relatively inexpensive, and involves very low radiation dose to the patient. Developments in DEXA equipment and software allow an accurate and differential estimate of visceral adipose tissue. This review summarizes the clinical practical application of whole-body DEXA values, with use of muscle and fat mass indices in the diagnostic workup of low muscle mass, sarcopenia, and sarcopenic obesity according to the most recent studies and guidelines.