Jahanlou Alireza Shahab, Kouzekanani Kamiar
Department of Health Education, Hormozgan University of Medical Sciences, Bandar Abbas, Iran; Visiting Scholar, College of Education, Texas A&M University-Corpus Christi, USA.
Department of Quantitative Methodology, College of Education, Texas A&M University-Corpus Christi, USA.
Iran J Med Sci. 2016 Jul;41(4):288-95.
The study was conducted to examine the comparability of the BMI and Gallagher's classification in diagnosing obesity based on the cutoff points of the gold standards and to estimate suitable cutoff points for detecting obesity among Iranians.
The cross-sectional study was comparative in nature. The sample consisted of 20,163 adults. The bioelectrical impedance analysis (BIA) was used to measure the variables of interest. Sensitivity, specificity, positive predictive power (PPV), and negative predictive power (NPV) were used to evaluate the comparability of the two classification methods in detecting obesity.
The BMI wrongly classified 29% of the obese persons as overweight. In both classifications, as age increased, the accuracy of detecting obesity decreased. The Gallagher's classification is better than MBI in detecting obesity in men with the exception of those older than 59 years. In females, the BMI was better in determining sensitivity. In both classifications, either female or male, an increase in age was associated with a decrease in sensitivity and NPV with the exception of the BMI for the 18 year olds. Gallagher can correctly classify males and females who are less than 40 and 19 years old, respectively.
Gallagher's classification is recommended for non-obese in both sexes and in obese males younger than 40 years old. The BMI is recommended for obese females. The suitable cutoff points for the BMI to detect obesity are 27.70 kg/m(2) for females and males, 27.70 kg/m(2) for females, and 27.30 kg/m(2) for males.
本研究旨在根据金标准的切点来检验体重指数（BMI）和加拉格尔分类法在诊断肥胖方面的可比性，并估算伊朗人群中检测肥胖的合适切点。
本横断面研究具有比较性质。样本包括20163名成年人。采用生物电阻抗分析（BIA）来测量相关变量。使用灵敏度、特异性、阳性预测值（PPV）和阴性预测值（NPV）来评估两种分类方法在检测肥胖方面的可比性。
BMI将29%的肥胖者错误分类为超重。在两种分类中，随着年龄增长，检测肥胖的准确性降低。除了59岁以上的男性，加拉格尔分类法在检测男性肥胖方面优于BMI。在女性中，BMI在确定灵敏度方面表现更好。在两种分类中，无论男性还是女性，除了18岁人群的BMI外，年龄增加与灵敏度和NPV降低相关。加拉格尔分类法能够分别正确分类年龄小于40岁的男性和小于19岁的女性。
对于非肥胖者以及40岁以下的肥胖男性，推荐使用加拉格尔分类法。对于肥胖女性，推荐使用BMI。BMI检测肥胖的合适切点为女性27.70kg/m²、男性27.30kg/m²。
