中国0～18岁儿童、青少年体块指数的生长曲线

Body mass index growth curves for Chinese children and adolescents aged 0 to 18 years

目的研究制定0～18岁中国儿童的体块指数（BMI）生长参照值及生长曲线。方法根据“2005年中国九市7岁以下儿童体格发育调查”及“2005年中国学生体质与健康调研”所获得的资料，采用九省市93702名0～19岁（差1天未满19岁）城区健康儿童青少年的身高（3岁以下测量身长）、体重测量数据，计算BMI值并应用LMS方法对数据进行拟合修匀，通过L、M、S三个参数计算产生所需要的百分位和标准差单位（z分值）数值并绘制相应的曲线图。采用与中国成人BMI界值点接轨的方法探讨中国儿童超重肥胖的筛查界值点。结果制定出0～18岁儿童的BMI百分位数及标准差单位生长参照值及曲线图，并计算出了筛查2～18岁儿童超重肥胖的参考界值点。本参照曲线与世界卫生组织（WHO）BMI曲线及美国疾病预防控制中心2000年（CDC2000）曲线进行比较，三者之间存在明显的差异，尤其是在青春期、第97百分位（P97）上。总体上中国男童BMI在P97处于三者之间，而女童最低。与日本比较，在P97也有明显差异。结论使用BMI生长曲线图有利于儿童青少年的生长与营养监测，早期识别儿童的超重和肥胖，建议在临床工作及预防保健服务领域推广使用。

Objective To construct the body mass index （BMI） reference data and curves for Chinese children and adolescents from birth to 18 years of age. Methods Data from two national representative cross-sectional surveys which were The National Growth Survey of Children under 7 years in the Nine Cities of China in 2005 and The Physical Fitness and Health Surveillance of Chinese School Students in 2005. Height （ length was measured for children under 3 years） and weight data of 93 702 urban healthy children from nine cities/provinces used to calculate the BMI. The LMS method was used to smooth the BMI, with estimates of L, M, and S parameters, values of percentile and Z-score curves which were required were calculated, and then standardized growth charts were generated. Adult cut-offs for overweight and obesity at 18 years was used to study the cut-offs for children 2 to 18 years of age. Results The smoothed percentiles and Z-scores reference data and curves of BMI-for-age for boys and girls aged 0-18 years were made out respectively. BMI cut-off values for overweight and obesity for children from 2 to 18 years of age were also defined. At 18 years, the BMI values are equivalent to the overweight cut-off （ ≥24 kg/m^2 ） and obesity cut-off （ ≥28 kg/m^2 ） for Chinese adults. Comparison with the reference of the WHO and 2000 CDC for the United States, there were some difference among them, at the 97th percentile curve there was a big difference between Chinese and U. S. adolescents. On the whole, the China BMI curve for boys was higher than the new WHO curve and lower than 2000 CDC at 97 percentile curve, but the China BMI curve for girls was lowest among the three curves. There was also significant difference between China and Japan BMI values at 97 percentile curve. Conclusion BMI growth curves are very useful in child growth monitoring and nutritional surveillance, discovering overweight and obesity. The BMI growth charts are recommended for use in pediatric clinic and public health service.