Diagnostic accuracy of body mass index to identify obesity in older adults: NHANES 1999-2004.
Diagnostic accuracy of body mass index to identify obesity in older adults: NHANES 1999-2004.
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DOI：
10.1038/ijo.2015.243
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发表时间：
2016-05
期刊：
影响因子：
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通讯作者：
Lopez-Jimenez F
中科院分区：
文献类型：
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作者：
Batsis JA;Mackenzie TA;Bartels SJ;Sahakyan KR;Somers VK;Lopez-Jimenez F
随着年龄的增长，身体成分的变化导致肥胖增加和肌肉质量减少，使肥胖症的诊断具有挑战性。传统的人体测量法，包括体重指数（BMI），虽然易于临床使用，但可能会误解肥胖。我们使用双能X线吸收法（DEXA）评估老年人肥胖程度，以确定BMI诊断的准确性。采用1999-2004年全国健康与营养检查调查，通过DEXA测量确定≥ 60岁的成年人。按性别（男性≥25%;女性≥35%）和体重指数（BMI）≥25和≥ 30 kg/m2将其分类（是/否）为体脂升高。评估BMI的诊断性能。在BMI/体脂不一致的情况下比较代谢特征。根据NHANES指南进行加权和分析。我们确定了4,984名受试者（男性：2,453名;女性：2,531名）。男性的平均BMI和%体脂分别为28.0kg/m2和30.8%，女性为28.5kg/m2和42.1%。BMI ≥ 30 kg/m2的敏感性较低，特异性中等偏高（男性：32.9%和80.8%，一致性指数0.66;女性：38.5%和78.5%，一致性指数0.69），正确分类肥胖受试者的比例为41.0%和45.1%。BMI ≥ 25 kg/m2具有中等高的敏感性和特异性（男性：80.7%和99.6%，一致性0.81;女性：76.9%和98.8%，一致性0.84），正确分类80.8%和78.5%的肥胖受试者。在BMI<30 kg/m2的受试者中，分别有67.1%的男性和61.5%的女性认为体脂升高。对于BMI≥ 30 kg/m2的受试者，在60- 69.9岁至≥ 80岁的男性和女性中，敏感性分别从40.3%降至14.5%和44.5%降至23.4%，而特异性保持升高（>98%）。在这两个年龄组的男性和女性中，使用30 kg/m2的临界值对肥胖的正确分类从48.1%下降到23.9%，从49.0%下降到19.6%。传统的测量方法很难识别老年人的肥胖。在老年人中，BMI可能是肥胖的次优指标。
Body composition changes with aging lead to increased adiposity and decreased muscle mass, making the diagnosis of obesity challenging. Conventional anthropometry, including body mass index (BMI), while easy to use clinically may misrepresent adiposity. We determined the diagnostic accuracy of BMI using dual energy x-ray absorptiometry (DEXA) in assessing the degree of obesity in older adults. The National Health and Nutrition Examination Surveys 1999–2004 were used to identify adults aged ≥60years with DEXA measures. They were categorized (yes/no) as having elevated body fat by gender (men≥25%; females ≥35%) and by body mass index (BMI) ≥25 and ≥30kg/m2. The diagnostic performance of BMI was assessed. Metabolic characteristics were compared in discordant cases of BMI/body fat. Weighting and analyses were performed per NHANES guidelines. We identified 4,984 subjects (men:2,453; female:2,531). Mean BMI and % body fat was 28.0kg/m2 and 30.8% in men, and 28.5kg/m2 and 42.1% in females. A BMI ≥30kg/m2 had a low sensitivity and moderately high specificity (men:32.9% and 80.8%, concordance index 0.66; females:38.5% and 78.5%, concordance 0.69) correctly classifying 41.0 and 45.1% of obese subjects. A BMI ≥25kg/m2 had a moderately high sensitivity and specificity (men:80.7% and 99.6%, concordance 0.81;females:76.9% and 98.8%, concordance 0.84) correctly classifying 80.8 and 78.5% of obese subjects. In subjects with BMI<30kg/m2 body fat was considered elevated in 67.1% and 61.5% of males and females, respectively. For a BMI≥30kg/m2, sensitivity drops from 40.3 to 14.5% and 44.5 to 23.4%, while specificity remains elevated (>98%),in males and females, respectively in those 60–69.9years to subjects aged ≥80years. Correct classification of obesity using a cutoff of 30kg/m2 drops from 48.1 to 23.9% and 49.0 to 19.6%, in males and females in these two age groups. Traditional measures poorly identify obesity in the elderly. In older adults, BMI may be a suboptimal marker for adiposity.