Endocrine Abstracts

JOINT736

Background: Previous studies have investigated the possible relationship between breastfeeding and pubertal timing in girls, but evidence in boys is limited and the underlying mechanisms remain to be elucidated. We aimed to examine the effect of breastfeeding during the first 4–6 months of life on central precocious puberty (CPP) in boys and girls, and whether this relationship was mediated by prepubertal adiposity using nationwide cohort in South Korea.

Methods: Children who underwent regular health check-up from National Health Screening Program for Infant and Children at 4–6 months (Exam I) and 66–71 months (Exam Vll) were included. Primary feeding practices were collected from primary caregiver-reported questionnaire during Exam I. Multivariable Cox proportional hazard regression was used to estimated adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for CPP after adjusting for preterm birth, multiple birth, low birth weight, overweight or obesity status in prepubertal age, maternal age at childbirth, gestational diabetes or hypertension, cesarean section, socioeconomic status and residence. Additionally, we performed mediation analysis to investigate the mediating effect of prepubertal adiposity on association between breastfeeding and CPP.

Results: Among a total of 322, 731 children (135, 232 boys and 187, 499 girls), 148, 402 (46.0%) were exclusively breastfed, 112, 738 (34.9%) were formula-fed, and 61, 591 (19.5%) were mixed-fed. In both boys and girls, formula-fed children had the largest risk of CPP (aHR 1.152 [95% CI 1.100–1.207] in boys, aHR 1.583 [95% CI 1.225-2.045] in girls), followed by mixed-fed children (aHR 1.130 [95% CI 1.068–1.195] in boys, aHR 1.440 [95% CI 1.063–1.950] in girls), compared to exclusive breastfed children. Mediation analysis revealed that lack of breastfeeding during early infancy was associated with an increased likelihood of developing prepubertal adiposity, which subsequently elevated the risk of CPP in both sexes.

Conclusion: Breastfeeding during the first 4–6 months of life was associated with a lower risk of CPP in both boys and girls. Prepubertal adiposity significantly medicated the relationship between feeding practices and CPP, highlighting the critical role of early-life nutrition in pubertal timing.