老年人体脂率预测公式的构建及验证

Development and validation of a prediction equation for estimating body fat percentage in older adults

目的基于常用人体测量学数据和人口学数据构建老年人体脂率预测公式,并验证其预测效果。方法采用分层便利抽样法采集1025名老年人的人体测量学数据(身高、体质量及腰围等)、人口学数据(性别、年龄等)和体脂率数据。随机分为建模组(820名)和验证组(205名)。以生物电阻抗分析仪(BIA)测得的体脂率为金标准,采用多元线性逐步回归分析法构建预测公式,ROC曲线下面积评价其预测效能,Bland-Altman散点图和林氏一致性系数验证预测公式与BIA的一致性。结果BMI、性别、身高、腰围、年龄进入体脂率预测公式。预测公式ROC曲线下面积为0.910,灵敏度为92.9%,特异度为89.1%。预测公式与BIA测得体脂率的差值均数为-0.021%,95%一致性区间(LOA)为(-6.605%,6.562%),95%LOA的95%CI为(-7.397%,7.354%);与BIA测得体脂率的林氏一致性系数为0.883。结论构建的老年人体脂率预测公式可靠,可用于老年人肥胖预防与管理。

Objective To develop a prediction equation for estimation of body fat percentage in elderly populations based on anthropometric data and demographic data,and to verify its prediction power.Methods A total of 1,025 elderly adults were selected by stratified convenience sampling and their anthropometric data(e.g.height,weight and waist circumference,etc.),demographic data(e.g.gender and age,etc.)and body fat percentage were measured.They were randomized into a model set of 820 and a validation set of 205.Using body fat percentage by bioelectrical impedance analysis(BIA)as the gold standard,stepwise multiple li-near regression was used to develop the prediction equation.ROC curve was used to evaluate the prediction power.The Bland-Altman diagram and concordance correlation coefficient(CCC)were used to verify the consistence of prediction equation and BIA.Results A new prediction equation was developed,based on BMI,gender,height,waist circumference and age.The area under ROC curve was 0.910,the sensitivity was 92.9%,and the specificity was 89.1%.The mean difference between the prediction equation and BIA was-0.021%,and the 95%limits of agreement(LOA)were-6.605%and 6.562%(with a 95%confidence interval of-7.397%to 7.354%).The CCC value between the prediction equation and BIA was 0.883.Conclusion The formula is valid for estimation of body fat percentage in older people and can be used in prevention and management of obesity.