Objectives: To study the association between early-life factors (including birth weight, method of birth, gestational age, and history of gestational metabolic disorders) and pubertal timing in girls.
Methods: The stratified cluster sampling method was used to select the girls in grades 2-3 and 7-8 from three primary schools and three middle schools in Guangzhou, China from March to December, 2019, and breast development was examined for all girls. A questionnaire survey was performed to collect the information on early-life factors. The multivariate logistic regression model was used to evaluate the association of gestational metabolic disorders, birth weight, method of birth, and gestational age with pubertal timing in girls. The Bootstrap method was used to assess the mediation effect of body mass index (BMI) (Z score) between high birth weight (≥4 000 g) and pubertal timing.
Results: A total of 1 665 girls were enrolled, among whom 280 (16.82%) were judged to have early pubertal timing. The multivariate logistic regression analysis showed that high birth weight was associated with the increased risk of early pubertal timing (OR=2.12, 95%CI: 1.19-3.66, P=0.008). Nevertheless, no significant association was observed between other early-life factors and pubertal timing (P>0.05). The OR for the mediation effect of BMI (Z score) between high birth weight and early pubertal timing was 1.25 (95%CI: 1.09-1.47), accounting for 29.33% of the total effect of high birth weight on early pubertal timing.
Conclusions: High birth weight is associated with the increased risk of early pubertal timing in girls, and overweight/obesity may play a partial mediating role in the association between high birth weight and early pubertal timing in girls.
目的: 探讨出生体重、出生方式、胎龄和母亲妊娠期代谢性疾病病史等生命早期因素与女生青春发动时相的关系。方法: 2019年3—12月采用分层整群抽样方法选取广州市3所小学2、3年级和3所中学7、8年级的女生进行乳房发育检查，并通过问卷调查收集学生的生命早期因素。采用多因素logistic回归法分析母亲妊娠期代谢性疾病史、出生体重、出生方式和胎龄与女生青春发动时相的关联。采用Bootstrap法对体重指数（body mass index，BMI）（Z值）在高出生体重（≥4 000 g）与青春发动时相关系中的中介效应进行检验。结果: 共纳入1 665例女生，其中280例（16.82%）判断为青春发动时相提前。多因素logistic回归分析显示，高出生体重与女生青春发动时相提前风险增高存在显著关联（OR=2.12，95%CI：1.19~3.66，P=0.008）。其余生命早期因素与青春发动时相的关联无统计学意义（P>0.05）。BMI（Z值）在出生体重与青春发动时相关系中的中介效应OR为1.25（95%CI：1.09~1.47），在高出生体重对青春发动时相提前总效应中占比29.33%。结论: 高出生体重与女生青春发动时相提前风险增高之间存在关联，超重/肥胖在其中发挥部分中介作用。.
Keywords: Birth weight; Body mass index; Gestational metabolic disorder; Girl; Pubertal timing.