Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, USA.
Obesity (Silver Spring). 2010 Nov;18(11):2227-33. doi: 10.1038/oby.2010.5. Epub 2010 Jan 28.
Accurate methods for assessing body composition in subjects with obesity and anorexia nervosa (AN) are important for determination of metabolic and cardiovascular risk factors and to monitor therapeutic interventions. The purpose of our study was to assess the accuracy of dual-energy X-ray absorptiometry (DXA) for measuring abdominal and thigh fat, and thigh muscle mass in premenopausal women with obesity, AN, and normal weight compared to computed tomography (CT). In addition, we wanted to assess the impact of hydration on DXA-derived measures of body composition by using bioelectrical impedance analysis (BIA). We studied a total of 91 premenopausal women (34 obese, 39 with AN, and 18 lean controls). Our results demonstrate strong correlations between DXA- and CT-derived body composition measurements in AN, obese, and lean controls (r = 0.77-0.95, P < 0.0001). After controlling for total body water (TBW), the correlation coefficients were comparable. DXA trunk fat correlated with CT visceral fat (r = 0.51-0.70, P < 0.0001). DXA underestimated trunk and thigh fat and overestimated thigh muscle mass and this error increased with increasing weight. Our study showed that DXA is a useful method for assessing body composition in premenopausal women within the phenotypic spectrum ranging from obesity to AN. However, it is important to recognize that DXA may not accurately assess body composition in markedly obese women. The level of hydration does not significantly affect most DXA body composition measurements, with the exceptions of thigh fat.
评估肥胖和神经性厌食症（AN）患者身体成分的准确方法对于确定代谢和心血管危险因素以及监测治疗干预非常重要。我们的研究目的是评估双能 X 射线吸收法（DXA）测量绝经前肥胖、AN 和正常体重女性腹部和大腿脂肪以及大腿肌肉量的准确性，并与计算机断层扫描（CT）进行比较。此外，我们还希望通过生物电阻抗分析（BIA）评估水合作用对 DXA 衍生身体成分测量的影响。我们共研究了 91 名绝经前妇女（34 名肥胖，39 名 AN，18 名正常体重对照）。我们的研究结果表明，AN、肥胖和正常体重对照组中 DXA 和 CT 衍生的身体成分测量之间存在很强的相关性（r = 0.77-0.95，P < 0.0001）。在控制总体水量（TBW）后，相关系数相当。DXA 躯干脂肪与 CT 内脏脂肪相关（r = 0.51-0.70，P < 0.0001）。DXA 低估了躯干和大腿脂肪，高估了大腿肌肉量，且这种误差随着体重的增加而增加。我们的研究表明，DXA 是一种在从肥胖到 AN 的表型范围内评估绝经前妇女身体成分的有用方法。然而，重要的是要认识到，DXA 可能无法准确评估明显肥胖女性的身体成分。水合水平不会显著影响大多数 DXA 身体成分测量值，除了大腿脂肪。
