Abstract: Background　As Shanghai experiences a rapid economic development，it is also facing an obesity epidemic among students.Therefore，understanding the distribution of body mass index（BMI） and the prevalence of obesity among students in Shanghai is of great importance for revising China's standard definition for child obesity and delivering precise interventions for obesity children.Objective　To analyze BMI distribution characteristics and obesity epidemic in students from Shanghai's Minhang District，providing scientific evidence for the development of health policies concerning obesity control in primary and middle school students in China.Methods　Participants were 95 360 primary and middle school students（49 926 boys and 45 434 girls） selected from those undergoing physical examination in Minhang District in 2016.All of them had a complete record of demographic，height and weight data，and aged 84 months（7 years） and over but younger than 216 months（18 years）.The fitted growth curve of BMI percentiles was graphed by the generalized additive modelling of location，scale，and shape technique，and was compared with the fitted BMI percentile curves from nine cities' data obtained in 2005（the nine cities being Beijing，Harbin，Xi'an，Shanghai，Nanjing，Wuhan，Guangzhou，Fuzhou and Kunming which were censored for the 2005 Chinese Students' Physique and Health Survey conducted by the Ministry of Education）.The rates of standardized overweight，obesity and overweight-obesity were calculated by the norm levels of the 7-18-year-old population in the 2010 Chinese Census，and were compared with those of both 7-18-year-old girls and boys in cities with a majority of Han population obtained in 2014（the sample data taken from the 2014 Chinese Students' Physique and Health Survey conducted by the Ministry of Education）.Results　The BMI percentile curves of both boys and girls showed a rising trend with age.In the same percentiles，boys' BMI curves were all higher than those of girls without cross.Compared with the fitted BMI percentile curves from nine cities' data obtained in 2005，the same trend was observed that the BMI rose with the increase of age for both boys and girls.However，at the same age，the BMI of these students in Minhang District were all higher than those from the nine cities' data.The standardized overweight rates，obesity rates，and overweight-obesity rates of male students in Minhang District were 15.9%，20.6%，and 36.5% respectively，while those of female students were 7.8%，12.8 %，and 20.6%，respectively；both were higher than the average level in cities with a majority of Han population in 2014.At the primary school level（age group of 7–11 years），the standardized overweight-obesity rates in boys were higher in public schools and category Ⅰ private schools than in category Ⅱ private schools（χ2=124.36，39.88，respectively，both P<0.001）.The standardized overweight-obesity rates in girls were higher in public schools than in category Ⅰ and category Ⅱ private schools（χ2=12.87，43.78，respectively，both P<0.05）.At the middle school level（age group of 12-18 years），standardized overweight and obesity rates for boys were significantly higher in categoryⅠ private schools than they were in public schools（χ2=15.08，P<0.05）.However，no difference was observed among girls across categoryⅠ private schools and public schools（χ2=1.91，P=0.17）.Conclusion　Based on the data from the primary and middle school students in Minhang District，Shanghai，the BMI percentile curve rose as age increased for both genders.The BMI curves for boys were higher than those for girls in the same percentile.In addition，the overweight and obesity rates were higher in boys.Corresponding community-school-family linked interventions should be carried out as soon as possible to lay an early and solid foundation for reducing the prevalence of chronic diseases in adults in China.

Key words: Overweight, Obesity, Students, Body mass index, Sex distribution, Health surveys

摘要： 背景　随着我国经济的快速发展，上海市面临着严峻的学生肥胖流行现状。因此，了解上海市学生体质指数（BMI）分布情况及肥胖流行现状，对我国进行儿童肥胖标准的修订和精准干预十分重要。目的　分析上海市闵行区学生BMI分布特征和肥胖流行现状，为我国制定相关卫生政策提供科学证据。方法　从上海市闵行区2016年度学生健康体格检查（以下简称体检）资料中，选取基本人口学信息、身高和体质量资料完整，月龄≥84个月（7岁）且<216个月（18岁）的中小学生作为研究对象，共95 360名（其中男生49 926名、女生45 434名）。采用广义可加模型拟合上海市闵行区中小学生BMI百分位数曲线；并以2010年全国第六次人口普查中7~18岁人口作为标准人口，计算其标准化超重率、肥胖率、超重肥胖合计率。将上海市闵行区中小学生BMI百分位数曲线及计算出的标准化超重率、肥胖率、超重肥胖合计率分别与“2005年九城数据”BMI百分位数曲线（源自教育部组织实施的“2005年中国学生体质与健康调查研究”中来自北京、哈尔滨、西安、上海、南京、武汉、广州、福州、昆明9个城市数据拟合的BMI百分位数曲线）、“2014年中国汉族城市男、女生数据”（源自教育部组织实施的“2014年中国学生体质与健康调研报告”中7~18岁汉族城市样本数据）进行比较。结果　上海市闵行区男、女生BMI百分位数曲线均呈现随年龄增长不断上升的趋势，相同百分位数男生曲线BMI均比女生曲线BMI高，且男女生之间没有交叉。与“2005年九城数据”拟合的BMI百分位数曲线相比，不同性别的上海市闵行区中小学生BMI随年龄上升趋势相同，但在相同年龄时上海市闵行区中小学生BMI均高于“2005年九城数据”。上海市闵行区男生标准化超重率、肥胖率、超重肥胖合计率分别为15.9%、20.6%、36.5%，女生为7.8%、12.8%、20.6%，均高于2014年全国汉族城市男、女生数据标准化水平。小学阶段（7~11岁）：公办学校和Ⅰ类民办学校男生标准化超重肥胖合计率高于Ⅱ类民办学校（χ2值分别为124.36、39.88，P值均<0.001），公办学校女生超重肥胖合计率高于Ⅰ类、Ⅱ类民办学校（χ2值分别为12.87、43.78，P值均<0.05）。中学阶段（12~18岁）：Ⅰ类民办学校男生标准化超重肥胖合计率高于公办学校（χ2=15.08，P<0.05），公办学校和Ⅰ类民办学校女生超重肥胖合计率比较，差异无统计学意义（χ2=1.91，P=0.17）。结论　上海市闵行区中小学群体中，男、女生BMI百分位数曲线均呈现随年龄增长不断上升的趋势，相同百分位数男生曲线BMI均较女生曲线BMI高；男生超重率和肥胖率较明显，建议卫生部门和教育部门联合采取社区-学校-家庭联动干预措施，为降低成年期慢性病患病率打好前期基础。

关键词: 超重, 肥胖, 学生, 体质指数, 性别分布, 健康调查