Metabolic Hormone Profiles in Breast Milk From Mothers of Moderate-Late Preterm Infants Are Associated With Growth From Birth to 4 Months in a Sex-Specific Manner

Abstract

Background: Differing environmental conditions experienced by mother-infant dyads may influence composition of the milk received by the infant. As a consequence, diverse milk compositional profiles may contribute to different postnatal outcomes, especially in infants facing adverse perinatal environments. We investigated whether variability in milk concentrations of key metabolic hormones is associated with different growth outcomes in infants born preterm, a perinatal complication known to impact on infant growth.Methods: Human milk samples were collected from 169 mothers of 191 infants enrolled in the DIAMOND trial, a randomized trial of nutrition for moderate-late preterm infants, at 5 and 10 days postpartum and again at 4 months' corrected age and analyzed for leptin, adiponectin and insulin-like growth factor (IGF)-1. Infant weight and body composition were measured at birth, discharge and 4 months' corrected age. Multiple linear regression models were used to examine correlations between milk hormone concentrations, weight z-scores and body composition at discharge and 4 months' corrected age, and weight gain from birth to 4 months' corrected age. Sex-specific interactions were examined.Results: Higher milk IGF-1 concentrations on day 5 after birth were associated with greater infant fat-free mass at 4 months' corrected age. Milk IGF-1 concentrations at 4 months were positively associated with fat mass and fat-free mass at 4 months in boys but not girls. Milk leptin concentrations on day 5 after birth were positively associated with fat mass at discharge from hospital, but negatively associated with fat mass at 4 months' corrected age. No significant association was found for milk adiponectin concentrations.Conclusion: Milk IGF-1 and leptin concentrations in mothers of moderate-late preterm babies are associated with different growth and body composition through to 4 months' corrected age and these associations are often different in boys and girls. The sex-specific effects of nutrient and hormone exposure during early life in preterm infants warrants further investigation to optimize the nutritional care these infants receive, particularly in hospital, where the same nutrition is provided to boys and girls.

Associations between maternal adiposity and appetite-regulating hormones in human milk are mediated through maternal circulating concentrations and might affect infant outcomes

“…We did not find any associations between neither HM leptin nor adiponectin and any of the growth outcomes, and the literature states conflicting results within this research area (25). Galante and colleagues found leptin concentrations in HM 5 days postpartum positively associated with infant fat mass at discharge for moderate-late preterm infants, however HM leptin was negatively associated with fat mass at 4 months' corrected age (57). A considerable unknown factor is the plausible mechanism assumed when posing hypotheses regarding HM composition and associations with infant outcomes.…”

Hormonal Determinants of Growth and Weight Gain in the Human Fetus and Preterm Infant

“…For example, leptin levels in preterm infants correlate with breast milk leptin levels [ 346 ]. One study reported that milk leptin concentrations on postnatal day 5 were positively associated with fat mass at NICU discharge, but negatively associated with fat mass at 4 months’ corrected age [ 347 ]. Another study found that total milk leptin intake in the first 28 postnatal days was positively associated with weight gain velocity and weight z-score at birth to 36 weeks’ postmenstrual age (PMA) [ 348 ].…”

“…In this study, adiponectin intake from milk was associated with greater length z-scores but lower head circumference z-scores at 36 weeks’ PMA. Another study found no correlation between milk adiponectin and growth outcomes [ 347 ]. Milk IGF-1 concentrations are associated with fat-free mass at 4 months’ corrected age, while milk ghrelin concentrations are associated with neonatal weight gain and linear growth [ 347 , 349 ].…”

“…Another study found no correlation between milk adiponectin and growth outcomes [ 347 ]. Milk IGF-1 concentrations are associated with fat-free mass at 4 months’ corrected age, while milk ghrelin concentrations are associated with neonatal weight gain and linear growth [ 347 , 349 ].…”