Abstract：Objective 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.
Guerrero-Preston R, Goldman LR, Brebi-Mieville P, et al. Global DNA hypomethylation is associated with in utero exposure to cotinine and perfluorinated alkyl compounds[J]. Epigenetics, 2010, 5(6): 539-546. PMID: 20523118. PMCID: PMC3322495. DOI: 10.4161/epi.5.6.12378.
Frontini MG, Srinivasan SR, Berenson GS. Longitudinal changes in risk variables underlying metabolic syndrome X from childhood to young adulthood in female subjects with a history of early menarche: the Bogalusa heart study[J]. Int J Obes Relat Metab Disord, 2003, 27(11): 1398-1404. PMID: 14574352. DOI: 10.1038/sj.ijo.0802422.
Ahlgren M, Melbye M, Wohlfahrt J, et al. Growth patterns and the risk of breast cancer in women[J]. N Engl J Med, 2004, 351(16): 1619-1626. PMID: 15483280. DOI: 10.1056/NEJMoa040576.
Jordan SJ, Webb PM, Green AC. Height, age at menarche, and risk of epithelial ovarian cancer[J]. Cancer Epidemiol Biomarkers Prev, 2005, 14(8): 2045-2048. PMID: 16103459. DOI: 10.1158/1055-9965.EPI-05-0085.
