(PTFS05-07-23) The Association of Human Milk Macronutrient Content With Early Childhood Growth and Neurodevelopment in Rural Bangladesh

Objectives: To examine the association of HM macronutrient content with: (1) child growth at 6 months and (2) neurodevelopment at 24 months in rural Bangladesh.

Methods: In the Projahnmo pregnancy-birth cohort in Sylhet, Bangladesh, we collected mid-feed HM specimens at 1 and 4 months postpartum. We analyzed macronutrient content using mid-infrared transmission spectroscopy (MIRIS AB) and calculated Atwater energy content. To account for mean exposure during the period of primary exclusive breastfeeding, we averaged 1- and 4-month macronutrient concentrations. Infant anthropometrics were measured at birth and 6 months and Z-scores calculated (Intergrowth-21 standards at birth; WHO growth standards at 6 months). We assessed global neurodevelopment using Bayley Scales of Infant Development-III (BSID-III) at 24 months. We used linear regression to model the association between macronutrient content (exposure) and infant growth and BSID-III scores (outcomes). We a priori controlled for maternal age, parity, and education, and infant gestational age. For models of longitudinal growth, we controlled for size at birth.

Results: We enrolled 99 mothers who provided 99 one-month and 88 four-month HM samples that were analyzed for macronutrients. Median energy content of HM samples was 22.9 kcal/oz at 1 month (IQR 20.6, 25.1) and 17.5 kcal/oz at 4 months (IQR 15.6, 21.2).  All infants had anthropometric measures. We completed BSID-III assessments among 80 infants at 24 months. We found that every 0.1 g/100ml of protein (1 and 4 month averaged value) was associated with an additional 1.20 head circumference Z-scores at 6 months of age (95% CI: 0.00, 2.40; p=0.05). On subgroup analysis, this effect was greatest among SGA infants (𝝱 2.07; 95% CI: 0.43, 3.72; p=0.015; n=37). Macronutrient content at individual time points (1- and 4-months) was not associated with 6 month Z-scores. There were no significant associations between HM macronutrient content and BSID-III scores in this cohort.

Conclusions: Energy content of HM significantly decreased from 1 to 4 months postpartum in this Bangladeshi lactation cohort. Higher averaged 1- and 4- month protein content was associated with greater head circumference Z scores at 6 months, particularly among SGA infants. HM macronutrient content was not associated with BSID-III scores at 24 months in this cohort.

Funding Sources: NICHD, UNC OGHE