北京市儿童青少年青春期发育与肥胖相关关系的研究

Relationship between precosious puberty and obese status in Beijing children and adolescents

目的分析北京市6～18岁儿童青少年青春期发育与超重肥胖的关系。方法利用2004年北京市儿童青少年代谢综合征调查总样本中19085名6～18岁儿童青少年的青春期发育、体重指数（BMI）和体脂含量百分比（FMP）等数据。采用女性乳房和男性睾丸容积Tanner分期指标衡量青春期发育，结合个体年龄将群体分为早、晚发育组；以BMI和生物电阻抗法所测FMP作为反映体脂含量的指标；7～18岁人群超重和肥胖的诊断采用中国肥胖问题工作组（WGOC）推荐的中国学龄儿童青少年超重、肥胖筛查BMI值分类标准进行，6岁组采用美国疾病预防与控制中心2000年发布的儿童超重和肥胖BMI标准第P。和第氏分位值进行诊断；采用多元线形回归、Logistic回归分析早发育与体脂含量和超重、肥胖的相关联系。结果早发育组的超重（合并肥胖）率和肥胖率均高于晚发育组，女性两组间差异大于男性；控制可能的混杂因素后，女性BMI和FMP与早发育呈正相关（BMI：13=2．25，P〈0．001；FMP：13=4．55，P〈0．001）；而男性BMI和FMP与早发育的联系相反，早发育组的BMI高于晚发育组，而FMP却低于晚发育组；以晚发育为参照组，控制年龄、城郊居住地等因素的影响后。早发育预测超重、肥胖的OR值（95％CI）：女性为3．39（2．94～3．92）和3．12（2．53～3．85），男性为1．12（0．96～1．31）和1．31（1．06～1．62）。结论北京市儿童青少年青春期发育与肥胖密切相关，在评价超重、肥胖率及进行不同地区间肥胖流行状况的比较时，要注意青春期发育的效应修正作用。

Objective To examine the influence of precosious puberty on fatness in children and adolescents of Beijing, and compare their relationship in boys with girls. Methods 19 085 children and adolescents （9 418 boys, 9 667 girls） aged 6 - 18 years who participated in the program of Beijing Children and Adolescent Metabolic Syndrome study （BCAMS） and had complete anthropometry （weight, height, fat mass percentage by bioelectrical impedance analysis） and sexual maturation （SM） data. Overweight and obesity among children aged 7 - 18 years were defined according to sex-age-specific body mass index （BMI） cutoffs recommended by Chinese Working Group on Obesity （WGOC）, the 85^th and 95^th percentiles of BMI from US 2000 CDC Growth Charts （CDC2000） were used for children aged 6 years. Using the status quo method, the median age for each certain Tanner stage （ Ⅱ, Ⅲ, Ⅳ, Ⅴ ） was calculated. Based on each individual＇s age and SM status （ Tanner stages： breast stages for girls and testicular volume for boys, pubic hair for both genders）, the subjects were classified as early maturers （those who reached a certain Tanner stage earlier than the median age for that stage, and average and later maturers （ those who reached a certain Tanner stage equal to and later than the median age for that stage）. Using multiple linear regression model, associations between fatness （ BMI and FMP） and SM were systematically examined. Logistic regression analysis was performed to test how early maturation affected the risks for overweight and obesity. Results Early SM was positively associated with obesity in both girls and boys. The prevalence of combined overweight in early maturers versus the average and later maturers was 31.0% versus 24. 7% in boys and 30. 7% versus 11.8% in girls; the figures for obesity were 14.6% versus 9.7% and 13.5% versus 4.4%, respectively. Fatness （BMI and FMP） was associated with early maturation in girls, early maturing girls were fatter than counterparts. But the associations between BMI and FMP with early maturation in boys were in opposite directions, early maturing boys had higher BMI and lower FMP than counterparts. With covariates adjusted and using later maturing as the reference group, odds ratios and 95% confidence intervals for combined overweight were 1.12 （ 0. 96 - 1.31 ） for boys and 3. 39 （2.94 - 3.92 ） for girls, and for obesities were 1.31 （ 1.06 - 1.62） and 3. 12 （2. 53 -3. 85 ）, respectively. Conclusions Sexual maturation is associated with obesity in children and adolescents. Maturation status should be taken into consideration when assessing child and adolescent obesity.