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.
Bibliographical noteFunding Information:
Funding agencies: The present study used data from Mothers and Infants Linked for Healthy Growth (MILk) study. The MILk study is supported by an NIH National Institute of Child Health and Human Development grant (R01HD080444). Disclosure: The authors declared no conflict of interest. Author contributions: DAF and EWD conceived the project and were responsible for data collection. GSD completed the literature review, ran the statistical analyses, and wrote the manuscript. KMW and EWD assisted with manuscript writing and statistical analysis. LF and KDS assisted with data collection. AMT conducted all breast milk assays. JLH was responsible for data management. DRJ and LJL assisted with statistical analyses. EOK conducted data collection and management and assisted with manuscript writing. PMM helped to design the study, interpreted the statistical analyses, and assisted with manuscript writing. TCS collected data and assisted with manuscript writing. LH oversaw data collection and assisted with manuscript writing. All authors critically reviewed the manuscript and had final approval of the submitted and published versions. Clinical trial registration: ClinicalTrials.gov identifier NCT03301753. Additional Supporting Information may be found in the online version of this article. Received: 19 April 2018; Accepted: 16 December 2018; Published online 22 March 2019. doi:10.1002/oby.22409