ABSTRACT
OBJECTIVE: The aim of this study was to test associations of prepregnancy BMI, gestational weight gain, oral glucose challenge test results, and postpartum weight loss as predictors of breast milk leptin, insulin, and adiponectin concentrations and whether these relationships vary over time. METHODS: Milk was collected at 1 and 3 months from 135 exclusively breastfeeding women from the longitudinal Mothers and Infants Linked for Healthy Growth (MILk) study. Hormones were assayed in skimmed samples using ELISA. Mixed-effects linear regression models were employed to assess main effects and effect-by-time interactions on hormone concentrations. RESULTS: In adjusted models, BMI was positively associated with milk leptin (P < 0.001) and insulin (P = 0.03) and negatively associated with milk adiponectin (P = 0.02); however, the association was stronger with insulin and weaker with adiponectin at 3 months than at 1 month (time interaction P = 0.017 for insulin and P = 0.045 for adiponectin). Gestational weight gain was positively associated and postpartum weight loss was negatively associated with milk leptin (both P < 0.001), independent of BMI. Oral glucose challenge test results were not associated with these milk hormone concentrations. CONCLUSIONS: Maternal weight status before, during, and after pregnancy contributes to interindividual variation in human milk composition. Continuing work will assess the role of these and other milk bioactive factors in altering infant metabolic outcomes.
Subject(s)
Adiponectin/metabolism , Body Weight/physiology , Insulin/metabolism , Leptin/metabolism , Milk, Human/metabolism , Mothers , Adiponectin/analysis , Adult , Breast Feeding , Female , Glucose Tolerance Test , Humans , Infant, Newborn , Insulin/analysis , Leptin/analysis , Longitudinal Studies , Male , Middle Aged , Milk, Human/chemistry , Postpartum Period/metabolism , Pregnancy , Young AdultABSTRACT
OBJECTIVE: The goal of this study was to examine the associations of maternal weight status before, during, and after pregnancy with breast milk C-reactive protein (CRP) and interleukin 6 (IL-6), two bioactive markers of inflammation, measured at 1 and 3 months post partum. METHODS: Participants were 134 exclusively breastfeeding mother-infant dyads taking part in the Mothers and Infants Linked for Health (MILK) study, who provided breast milk samples. Pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) were assessed by chart abstraction; postpartum weight loss was measured at the 1- and 3-month study visits. Linear regression was used to examine the associations of maternal weight status with repeated measures of breast milk CRP and IL-6 at 1 and 3 months, after adjustment for potential confounders. RESULTS: Pre-pregnancy BMI and excessive GWG, but not total GWG or postpartum weight loss, were independently associated with breast milk CRP after adjustment (ß = 0.49, P < 0.001 and ß = 0.51, P = 0.011, respectively). No associations were observed for IL-6. CONCLUSIONS: High pre-pregnancy BMI and excessive GWG are associated with elevated levels of breast milk CRP. The consequences of infants receiving varying concentrations of breast milk inflammatory markers are unknown; however, it is speculated that there are implications for the intergenerational transmission of disease risk.
