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Author Notes:

Corresponding author: Amanda Thompson, Department of Anthropology, 301 Alumni Building CB#3115, Chapel Hill, NC 27599, althomps@email.unc.edu, Phone: 919-843-2060, Fax: 919-962-1243

We gratefully acknowledge the participating families and the technical and laboratory assistance provided by Patricia Whitten, James Millette, Amy Cobden, Juliet Alla and Betsy Russell.

We also thank Patricia Whitten, Carol Worthman and Dan Sellen for comments on earlier versions of this paper.

Subject:

Research Funding:

This study was supported in part by the Woodruff Fund Award, Robert H. Woodruff Health Sciences Center, Emory University and the National Science Foundation Dissertation Improvement Grant (NSF BCS#0424307).

The Carolina Population Center provided general support (NIH R24 HD050924).

Keywords:

  • Science & Technology
  • Life Sciences & Biomedicine
  • Anthropology
  • Biology
  • Life Sciences & Biomedicine - Other Topics
  • BIRTH-WEIGHT
  • BODY-COMPOSITION
  • BREAST-MILK
  • IGF-I
  • REPRODUCTIVE HORMONES
  • INFANT FORMULA
  • GROWTH
  • AGE
  • SERUM
  • MENARCHE

Prenatal and postnatal energetic conditions and sex steroids levels across the first year of life

Tools:

Journal Title:

American Journal of Human Biology

Volume:

Volume 25, Number 5

Publisher:

, Pages 643-654

Type of Work:

Article | Post-print: After Peer Review

Abstract:

Objectives Human biologists have documented variability in reproductive maturation, fertility, and cancer risk related to developmental conditions. Yet no previous studies have directly examined the impact of pre- and post-natal energetic environments on sex steroids in infancy, a critical period for hypothalamic-pituitary-gonadal axis development. Thus, we examined the impact of maternal characteristics, birth size, and feeding practices on fecal sex steroid production in a longitudinal sample of 31 American infants followed from 2 weeks to 12 months of age. Methods Maternal characteristics and birth size were collected at study enrollment, infant diet was assessed through weekly 24-hr food diaries, and anthropometrics were measured weekly. Fecal estradiol and testosterone levels were assessed weekly using validated microassay RIA techniques. Mixed models were used to test for associations between maternal and birth characteristics, feeding practices, and sex steroids across the first year of life. Formal mediation analysis examined whether the relationship between infant feeding and hormone levels was mediated by infant size. Results Maternal and birth characteristics had persistent effects on fecal sex steroid levels, with taller maternal height and larger birth size associated with lower estradiol levels in girls and higher testosterone levels in boys. Infant diet was also associated with sex steroid levels independently of infant size. Formula feeding was associated with higher estradiol levels in boys and girls and with higher testosterone in girls. Conclusion These results suggest that markers of early energy availability influence sex hormone levels with potential long-term consequences for reproductive development and function.

Copyright information:

VC 2013 Wiley Periodicals, Inc.

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