Body composition assessment by dual-energy X-ray absorptiometry (DXA)

Abstract

Body composition (BC) assessment is indispensable to evaluate nutritional status and thus health, both at the population and individual level, and to assess the efficacy of primary and secondary preventive nutritional strategies. Changes in BC, including the regional distribution of body fat, largely occur during pubertal transition, with marked differences between genders. They may, however, also occur in the elderly, who experience significant changes in the ratio between body fat and muscle with aging. The development and implementation of more sophisticated techniques (e.g. BC assessment at the molecular and atomic levels) could provide a major contribution to determining BC at different levels. This review discusses the application of dual-energy X-ray absorptiometry (DXA) on BC determination, given that DXA has the potential to provide overall and regional assessment of BC in terms of fat, lean mass and bone. DXA is widely used in many clinical settings primarily diagnosis osteoporosis. This article describes the use of whole-body DXA in assessing BC in patients with chronic diseases (e.g. metabolic syndrome) as well as in different sport activities to evaluate the effects of exercise.

Nutritional status and its relationship with different dimensions of functional status in patients with chronic obstructive pulmonary disease

“…In this context DEXA -method used in this study -has the potential to provide overall and regional assessment of body composition in terms of fat, lean, and bone masses 20 . Many studies that set Patients were not classified based on the presence of emphysema (lean look and significant weight loss) or chronic bronchitis (obese or without marked weight loss) since it is often difficult to distinguish these overlapping phenotypes.…”

Methods for Body Composition Analysis in Adults

“…22 Na -or 24 Na -elements are used for total body sodium and 42 K -is used for total body potassium. After the injection, 24 hours of urine is collected and radioactive material concentration, stable sodium or stable potassium concentrations are measured in plasma.…”

“…DEXA can also be used in large community-based studies. Due to the emission of tissue specific energy by X-rays, it directly measures body fat in line with the triple compartment model (fat tissue, bone and lean tissue) [24]. Following new developments in hardware and software, many recent studies have evaluated the differences among several DEXA scanners and DEXA was compared with other whole body composition analysis methods.…”

“…As trunk thickness increases, the measurement error increases [21]. Although DEXA measurements produce quite detailed and fairly accurate results for fat tissue mass, FFM and bone mineral content, its disadvantage is that it cannot be repeated frequently due to radiation exposure [24].…”

Formulación de una ecuación para predecir la masa grasa corporal a partir de bioimpedanciometría en adultos en un amplio rango de edad e índice de masa corporal

“…Esta técnica utiliza dos haces de rayos X de diferente energía, los que al atravesar los tejidos del organismo, son atenuados de manera diferente por el tejido mineral, masa magra no ósea y masa grasa 10 . Como modelo de evaluación de la composición corporal proporciona múltiples ventajas, destacando su alta exactitud, con un error de estimación del 1% para masa ósea y entre 1 y 3% para masa grasa, llegando a ser considerado uno de los métodos de referencia para el análisis de masa libre de grasa y masa grasa 3,11,12 . Sin embargo, por su elevado costo y menor accesibilidad que BIA, es de interés mejorar la fi abilidad y validez de esta última para el análisis de composición corporal, y así aprovechar sus ventajas.…”