Exclusive Breastfeeding Linked to Lower Risk of Central Precocious Puberty in Children: JAMA
South Korea: Researchers have found in a new South Korean nationwide cohort study that exclusive breastfeeding for the first 4–6 months was associated with a reduced risk of central precocious puberty (CPP) in both boys and girls, partly mediated by prepubertal adiposity.
The study, published in JAMA Network Open by Yunsoo Choe and colleagues from the Department of Pediatrics, Hanyang University Guri Hospital, investigated how early feeding practices may influence the onset of puberty. CPP, which refers to the unusually early activation of puberty, has been rising worldwide, raising concerns due to its long-term health implications.
The research analyzed data from 322,731 children (58.1% girls) enrolled in the South Korean National Health Insurance Service Database between 2007 and 2020. Children were assessed at routine health checkups at 4–6 months and again at 66–71 months of age. Feeding practices—whether exclusive breastfeeding, formula feeding, or mixed feeding—were reported by caregivers during infancy.
The study led to the following findings:
- 46% were exclusively breastfed, 34.9% formula-fed, and 19.1% mixed-fed.
- Formula-fed and mixed-fed infants had a higher risk of CPP than exclusively breastfed infants.
- Formula-fed boys had a 16% higher risk (AHR, 1.16), and formula-fed girls had a 60% higher risk (AHR, 1.60).
- Mixed-fed boys had a 14% higher risk (AHR, 1.14), and mixed-fed girls had a 45% higher risk (AHR, 1.45).
- Mediation analysis showed that prepubertal overweight or obesity accounted for 7.2% of the increased CPP risk in boys and 17.8% in girls associated with formula feeding.
- These findings indicate that the protective effect of breastfeeding works both directly and indirectly by supporting healthier body weight in early childhood.
“These findings highlight the critical role of early-life nutrition in shaping pubertal development,” the authors noted, suggesting that exclusive breastfeeding may help delay the early onset of puberty by reducing childhood adiposity.
Despite its large sample size and robust design, the study had several limitations. Information on maternal age at menarche, a known factor influencing puberty onset in girls, was unavailable. Only cases treated with gonadotropin-releasing hormone (GnRH) agonists were included, raising the possibility of under- or over-diagnosis due to insurance-related factors. The study also did not assess the effects of breastfeeding duration beyond 6 months or differences between direct breastfeeding and expressed milk feeding. Furthermore, overweight status was measured at a fixed age rather than across time, limiting the ability to capture changes in growth patterns.
The researchers concluded that exclusive breastfeeding during the first few months of life is linked to a lower risk of CPP in both sexes, with prepubertal weight status serving as a partial mediator. They emphasized the need for further prospective longitudinal studies to confirm these associations and explore the long-term implications for growth and development.
Reference:
Choe Y, Ryu S, Choi J, et al. Breastfeeding, Prepubertal Adiposity, and Development of Precocious Puberty. JAMA Netw Open. 2025;8(8):e2527455. doi:10.1001/jamanetworkopen.2025.27455
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