【摘要】 目的 探讨上海市男女童体质指数超重及肥胖最佳界值点及相应百分位。方法 (1)收集78379例(男39585例，女38794例)上海市2～19岁少年儿童身高、体重和年龄。(2)以上海市儿童身高别体重作为金标准，(体重≥中位数的110%为超重，≥中位数的120%为肥胖)，分析2～11.5岁45364例(男23233例，女22131例)儿童在不同的超重肥胖体质指数界值点的灵敏度和特异度，并绘制成受试者工作曲线(ROC)，从中确立最佳界值点及相应百分位曲线。结果 对上海男童BMI共分析了7个超重(17.9～27kg/m2)及9个肥胖界值点(17.9～30kg/m2)，其中超重切点24、24.5及25kg/m2的特异度分别为93.2%、96.0%及97.9%，灵敏度为94.9%、90.1%及83.7%。肥胖切点27、27.5及28kg/m2的特异度分别为78.3%、85.9%及91.0%，灵敏度为84.7%、77.7%及70.2%。对上海女童BMI共分析了6个超重点(17.3～25kg/m2)及8个肥胖界值点(17.3～29kg/m2)，其中超重切点22、22.5及23kg/m2的特异度分别为91.5%、95.6%及98.5%，灵敏度为96.6%、91.2%及81.6%。肥胖切点24、25及26kg/m2的特异度分别为65.9%、87.3%及96.3%，灵敏度为94.0%、77.9%及60.2%。结论 据ROC曲线上海市男童超重肥胖18岁时最佳BMI界值点分别为24.5及27.5kg/m2，女童为22.5及25kg/m2。其相应百分位男童分别为第79及92百分位，女童分别为79.2及93.2百分位。男女童最佳界值点不同，但相应百分位很接近。

    【关键词】 超重；肥胖；青少年儿童；受试者工作曲线；BMI界值点；百分位

    Study on the optimal BMI cut-off points for overweight and obesity of Shanghai children

    JIANG Yi-fang,LIN Zhong-fang,JU Mei-fang,et al.

    Children's Hospital Afficiated to Shanghai Jiaotong University,Shanghai 200040,China

    【Abstract】 Objective To study the optimal BMI cut-off points for overweight and obesity of Shanghai children and its corresponding percentiles.Methods 1) The data of height, weight and age of 78379 children (39585boys and 38794 girls) aged 2～19 years were collected from Shanghai in 1999～2002, including 45364 children (23233 boys and 22131girls) aged 2～11.5 years old. 2) Shanghai reference of weight for height is used as the gold standard. Overweight is defined as weight ≥110% of ideal weight, and obesity as weight ≥120% of ideal weight. 3) The receiver operating characteristic curve (ROC) was used to characterize the sensitivity and specificity of different BMI cutoff points in classifying overweight and obesity.Results 1) 7 cutoff points of BMI for overweight (17.9～27kg/m2) and 9 cutoff points of BMI for obesity (17.9～30kg/m2) for Shanghai boys are analyzed. The specificity of classifying overweight at 24, 24.5 and 25kg/m2 is 93.2%, 96.0% and 97.9% respectively, and sensitivity is 94.9%, 90.1% and 83.7% respectively. The specificity of classifying obesity at 27, 27.5 and 28kg/m2 is 78.3%, 85.9% and 91.0% respectively, and sensitivity is 84.7%, 77.7% and 70.2% respectively. 2) 6 cutoff points of BMI for overweight (17.3～25kg/m2) and 8 cutoff points of BMI for obesity (17.3～29kg/m2) for Shanghai girls are analyzed. The specificity of classifying overweight at 22, 22.5 and 23kg/m2 is 91.5%, 95.6% and 98.5% respectively, and sensitivity is 96.6%, 91.2% and 81.6% respectively. The specificity of classifying obesity at 24, 25 and 26kg/m2 is 65.9%, 87.3% and 96.3% respectively, and sensitivity is 94.0%, 77.9% and 60.2% respectively. Conclusion The optimal BMI cut-off points for overweight and obesity at 18 years old is 24.5 and 27.5kg/m2 for boys, and 22.5 and 25kg/m2 for girls respectively. The corresponding percentile for overweight is P79 for boys and P79.2 for girls, and for obesity is P92 for boys and P93.2 for girls respectively. The corresponding percentiles for overweight or obesity between genders is very closed. ......