672 - Associations of human milk appetite-regulating hormones and amino acids with infant growth in the first 6 months

Publication Number: 672.3656

Adrienne K. Bruder, University of Michigan Medical School, ANN ARBOR, MI, United States; Lindsay Ellsworth, University of Michigan Medical School, Chelsea, MI, United States; Julie Sturza, University of Michigan Medical School, Ann Arbor, MI, United States; Alison L. Miller, University of Michigan, School of Public Health, ANN ARBOR, MI, United States; Brigid Gregg, University of Michigan Medical School, Ann Arbor, MI, United States; Julie Lumeng, University of Michigan Medical School, Ann Arbor, MI, United States

Background: Developmental programming mechanisms behind childhood obesity risk include early dietary exposures through human milk. Appetite-regulating hormones, such as leptin and adiponectin, and amino acids are key bioactive factors in human milk. Understanding the associations of human milk components with infant growth is necessary to target future early intervention strategies to improve childhood health.

Objective: To evaluate maternal and infant characteristics associated with human milk components that may regulate appetite and test the hypothesis that these components at 2 months are associated with infant growth from 2 to 6 months.

Design/Methods: This study includes a subset of mother-infant dyads from a longitudinal observational cohort of term infants with a milk sample available at 2 months. Whole milk was analyzed for leptin and adiponectin by enzyme-linked immunosorbent assay, amino acids (glutamine/glutamic acid, histidine, and serine) by liquid chromatography-tandem mass spectrometry and macronutrients by mid-infrared human milk analyzer. Mothers reported maternal and infant characteristics and breastfeeding intensity was calculated. Infants were measured at 2, 4, and 6 months, and weight, length, and weight-for-length were z-scored (WFAz, LFAz, WFLz), and change in WFAz from 2 to 6 months calculated. Bivariate analysis was used to screen for dependent variables to be included in multivariate models. Multivariate models were used to test associations of maternal and infant characteristics with human milk components, and associations of these components with growth, while controlling for maternal and infant characteristics.

Results: The sample was 70 infants (mean gestational age 39.4 weeks, 56% female) and their mothers. Pre-pregnancy BMI was positively associated with milk leptin, energy, and fat. Gestational diabetes was associated with lower milk adiponectin. Breastfeeding intensity was negatively associated with leptin, adiponectin, and serine. Leptin was positively associated with WFLz at 4 months and leptin and adiponectin were positively associated with WFAz at 6 months. Leptin, protein, glutamine/glutamic acid, histidine, and serine were positively associated with change in WFAz from 2 to 6 months.

Conclusion(s): Markers of maternal metabolic health were associated with differences in leptin, adiponectin, and macronutrients. As infants received increasing exclusivity of human milk, there were changes in hormone and amino acid content. Multiple milk components evaluated at 2 months were positively associated with growth outcomes, suggesting a role of milk composition in growth in early infancy.

Table 1.
Beta coefficients and standard errors from multivariate models predicting milk components. Each model predicting each human milk component contained all maternal characteristics listed simultaneously. ^p < 0.10 *p < 0.05

Table 2.
Beta coefficients and standard errors from multivariate models predicting infant growth. Each model contained a single human milk component and controlled for a) 2 week or 2 month weight and/or b) pre-pregnancy BMI, as indicated by bivariate analyses. *p < 0.05 **p < 0.01

Table 1.
Beta coefficients and standard errors from multivariate models predicting milk components. Each model predicting each human milk component contained all maternal characteristics listed simultaneously. ^p < 0.10 *p < 0.05

Table 2.
Beta coefficients and standard errors from multivariate models predicting infant growth. Each model contained a single human milk component and controlled for a) 2 week or 2 month weight and/or b) pre-pregnancy BMI, as indicated by bivariate analyses. *p < 0.05 **p < 0.01