广西壮族人群体脂率与常规肥胖指标的关系及其切点值研究

Relationship between body fat percentage and conventional obesity indicators and its cut-off values in Guangxi Zhuang population

目的 探讨广西壮族自治区35~<75岁壮族人群体脂率(body fat percentage, BFP)与BMI和腰围(waist circumference, WC)的关系及其肥胖切点值。方法 基于2018―2019年广西壮族自治区少数民族自然人群慢性病前瞻性队列的基线调查资料,选取12 311名壮族人群作为研究对象。通过曲线拟合确定BFP与BMI、WC的曲线关系,利用多元线性回归模型分析BFP的主要影响因素,分别构建BMI、WC预测BPF回归方程以计算BPF的超重和肥胖切点值,以BMI、WC判定标准为金标准计算BFP相应切点值的灵敏度、特异度和受试者工作特征(receiver operating characteristic, ROC)曲线下面积(area under curve, AUC)评估其诊断价值。结果 BMI对BFP的预测价值优于WC;基于我国肥胖标准BMI为28 kg/m^(2)计算的BFP肥胖切点值在男性和女性中分别为23.4%和35.6%,AUC分别为0.732和0.847;对应的灵敏度和特异度,男性为0.581和0.882,女性为0.818和0.876。结论 在广西壮族自治区人群中,基于我国肥胖标准计算BFP切点值应以BMI为参考,计算出来的切点值在男性中低于国际标准,而以BMI≥30 kg/m^(2)时计算所得切点值均高于国际标准,其合理性还需综合考虑阳性预测值和未来肥胖相关疾病风险的研究进一步予以验证。

Objective To investigate the association of body fat percentage(BFP)with body mass index(BMI)and waist circumference(WC)in Zhuang people aged 35-<75 years in Guangxi,and to explore the cut-off values of obesity.Methods A total of 12311 participants were selected from the baseline survey of the Prospective Cohort study of Chronic Diseases in Natural Minority Populations in Guangxi Zhuang Autonomous Region in 2018-2019.First,the relationship between BFP and BMI and WC was determined by curve fitting.Then,multiple linear regression model was used to analyze the main influencing factors of BFP,and regression equations for BMI and WC to predict BPF were constructed to calculate the overweight and obesity cut-off values of BPF.Finally,using BMI and WC criteria as the gold standard,the sensitivity,specificity and the area under curve(AUC)the receiver operating characteristic(ROC)of BFP corresponding cut-off values were calculated to evaluate its diagnostic value.Results BMI was superior to WC in predicting BFP.Based on the Chinese standard BMI of 28 kg/m^(2),the BFP obesity cut-off values was 23.4%in men and 35.6%in women,and the AUC was 0.732 and 0.847,respectively.The corresponding sensitivity and specificity were 0.581 and 0.882 in males,and 0.818 and 0.876 in females.Conclusions In Guangxi Zhuang population,the BFP cut-off values calculated based on the Chinese obesity standard should be referred to BMI.The calculated obesity cut-off value for males is lower than the international standard.However,the cut-off values calculated with BMI≥30 kg/m^(2) are higher than the international standard.The rationality of the BFP cut-off values needs to be further verified by considering the positive predictive value and the risk of obesity-related diseases in the future.