中国9个城市3～7岁儿童腰围百分位数参照值的研究

目的 研究和制定中国3～7岁儿童的腰围百分位数参照值。方法 腰围数据来自2015年6-11月在北京、哈尔滨、西安、上海、南京、武汉、广州、福州、昆明9个城市开展的儿童体格发育调查，共调查26 480名3～7岁健康儿童。采用基于偏度、位置和变异的曲线平滑方法建立性别、年龄别腰围百分位数曲线。将获得的3～7岁儿童腰围P₇₅和P₉₀与已发表的中国7～18岁儿童青少年腰围界值点（P₇₅和P₉₀）进行对接验证。将本研究腰围P₅₀与国外相关研究数据进行比较分析。结果 获得3～7岁男、女童每半岁间隔的腰围P₅、P₁₀、P₁₅、P₂₀、P₂₅、P₅₀、P₇₅、P₈₀、P₈₅、P₉₀和P₉₅参照值。腰围值随年龄增长呈明显上升趋势，男童P₅₀从3岁的47.5 cm增长到7岁的54.2 cm、女童从3岁的47.0 cm增长到7岁的52.2 cm。各年龄组男童腰围的各百分位数值均略高于女童，差值波动范围0.4～3.6 cm。3～7岁男、女童腰围在不同百分位数上实测值与拟合值的差值波动范围-0.3～0.5 cm。9个城市男、女童3～7岁腰围P₇₅和P₉₀数值与中国7～18岁儿童青少年腰围界值点（P₇₅和P₉₀）在年龄上能实现较好的对接。中国3～7岁儿童腰围数值与国外相关研究的比较显示，随年龄增长腰围增加的趋势一致，但我国男童处于中等水平、女童处于中等偏低水平。结论 本研究建立了我国3～7岁儿童的腰围百分位数参照值，并实现与7～18岁儿童青少年腰围参照值的良好衔接，可供相关临床、预防保健及科研工作等参照使用。

Percentile reference value of waist circumference for Chinese children aged 3-7 years

Objective To study and establish the percentile reference values of waist circumference (WC) for Chinese children aged 3-7 years. Methods A total of 26 480 children aged 3-7 years were collected as part of the National Survey on Physical Growth and Development of Children in nine cities (Beijing, Harbin, Xi''an, Shanghai, Nanjing, Wuhan, Guangzhou, Fuzhou and Kunming) in China from June to November 2015. Sex- and age-specific smoothed percentile reference values of WC were established using the Lambda Mu Sigma method. The P₇₅ and P₉₀ curves of WC for children aged 3-7 years in this study were linked with the published P₇₅ and P₉₀ cut-off points for Chinese children and adolescents aged 7-18 years. The P₅₀ percentile of WC in this study was compared with the corresponding percentiles of several foreign studies. Results The P₅, P₁₀, P₁₅, P₂₀, P₂₅, P₅₀, P₇₅, P₈₀, P₈₅, P₉₀ and P₉₅ reference values of WC were obtained for boys and girls aged 3-7 years biannually, at the interval of every six months. Results showed that WC at the P₅₀ had significantly increased from 47.5 cm at the age of 3 to 54.2 cm at the age of 7 for boys and from 47.0 cm at the age of 3 to 52.2 cm for girls at the age of 7. The corresponding WC percentile values appeared a bit higher in boys than those in girls at the same age, with the differences from 0.4 to 3.6 cm. The differences between measured and fitted WC at each empirical percentile ranged from -0.3 to 0.5 cm for both boys and girls aged 3-7 years. The P₇₅ and P₉₀ values of WC for boys and girls aged 3-7 years in this study presented a consistent, continuous tendency on age with the published WC cut-off points (P₇₅ and P₉₀) for Chinese children and adolescent aged 7-18. The increasing trend of WC by age in Chinese children aged 3-7 years was consistent with those of foreign studies, at the middle level for boys and lower middle level for girls. Conclusions Through this study, we established the WC percentile values for Chinese children aged 3-7 years and achieved the continuity in age with the published WC cut-off points for Chinese children and adolescents aged 7-18. These established WC percentile values can be used as reference for clinical practice, health care and scientific research.