Topical Area: Maternal, Perinatal and Pediatric Nutrition
Determine the associations of i) maternal body mass index (BMI) with breast milk (BM) leptin concentration and ii) BM leptin concentration with infant breastfeeding behaviors, body composition, and growth.
Methods : We conducted a secondary analysis of 40 mother-infant dyads from a double-blind, randomized controlled trial of vitamin D supplementation during lactation (NCT 00412074). Study staff collected mother's BM and anthropometric data (weight, height, adiposity via DEXA scan) of mother and infant at 1 month (V1), 4 months (V4), and 7 months (V7) postpartum, and maternal report of breastfeeding behaviors at V1 and V4. BM leptin was measured using mesoscale discovery. Pearson’s correlation was used to determine the association between maternal BMI and BM leptin at V1 and V4. The association of BM leptin with infant breastfeeding (BF) behaviors (number of BF events per day, duration of each BF, interval between BF, and total time BF per day) and infant anthropometric measures (BMI-Z score, total fat mass, total lean mass, and change (Δ) in these measures between V1 and V4, V1 and V7, and V4 and V7) was examined using linear regression with adjustment for covariates.
Maternal BMI (mean 29.0 kg/m2, SD 5.1 kg/m2) positively correlated with BM leptin concentration at V1 (mean 1.1 ng/mL, SD; r=0.5, p=0.005) and V4 (mean 1.4 ng/mL, SD 1.5 ng/mL; r=0.6, p=0.001). Breast milk leptin was not associated with any measures of infant BF behaviors (Table 1). Greater BM leptin at V1 was associated with greater increase in lean mass from V1 to V4 (β=137.5 g higher change in lean mass per ng/mL increase of leptin, p=0.021) and greater BM leptin at V4 was associated with greater lean mass at V7 (β=269.6g per ng/mL increase of leptin p=0.04) (Table 2).
Higher maternal BMI was associated with higher BM leptin concentrations. Higher BM leptin was associated with higher lean mass accrual in the first year of life. We did not find evidence that BM leptin was associated with BF behaviors in this exclusively BF cohort. Further research should seek to understand the mechanisms by which BM leptin affects growth in early infancy.
Funding Sources :
Nutrition Obesity Research Consortium at Harvard; (NIH) 5R01HD043921, NIH RR01070; and UL1 TR000062.