244 - The association of breast milk growth hormone intake with early childhood growth and neurodevelopment in rural Bangladesh.

Publication Number: 1231.244

Krysten North, Brigham and Women's Hospital, Boston, MA, United States; Dwita Nitoya Esterini, Brigham and Women's Hospital, Cambridge, MA, United States; Rasheda Khanam, Johns Hopkins University, Baltimore, MD, United States; Sophie Driker, Brigham and Women's Hospital, Somerville, MA, United States; Sayedur Rahman, Projahnmo Research Foundation, Skelleftea, Vasterbottens Lan, Sweden; Salahuddin Ahmed, Projahnmo Research Foundation, Dhaka, Dhaka, Bangladesh; Nabidul Chowdhury, Projahnmo Research Foundation, Dhaka, Dhaka, Bangladesh; Olivia E. Graham, Brigham and Women's Hospital, Cedar Hill, TX, United States; Matthew A. Manoj, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States; Brij Bhushan, New York University, Abu Dhabi, Abu Dhabi, Abu Dhabi, United Arab Emirates; Maria J. Hernandez Woodbine, Norwalk Hospital, Norwalk, CT, United States; Mandy Belfort, Harvard Medical School, Boston, MA, United States; Abdullah H. Baqui, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States; Sarbattama Sen, Women & Infants Hospital of Rhode Island, providence, RI, United States; Anne CC Lee, Warren Alpert Medical School of Brown University, Providence, RI, United States

Background: Breast milk contains numerous bioactive components, including growth hormones. Many hormones present in breast milk are known to play a role in tissue and nerve growth, processes that are critical during early childhood. Scant evidence exists on the relationship between breast milk growth hormones and early childhood growth and development.

Objective: To examine the associations of breast milk growth hormone intake with: (1) child growth at 6 and 12 months and (2) neurodevelopment at 24 months in rural Bangladesh.

Design/Methods: We collected breast milk samples from a subgroup of participants in the Projahnmo pregnancy-birth cohort in Sylhet, Bangladesh. Milk specimens were hand-expressed mid-feed samples at 2 and 5 months postpartum. We used ELISA to measure the intake of hormones known to play a role in growth (brain-derived neurotrophic factor [BDNF], beta-fibroblast growth factor [b-FGF], glial cell line-derived neurotrophic factor [GDNF], beta-nerve growth factor [bNGF], vascular endothelial growth factor [VEGF], and leptin). We calculated the daily intake of each hormone using measured concentrations and estimated daily milk volumes, determined by test weights and breastfeeding diaries. To account for mean exposure during the study period, we averaged 2- and 5-month hormone intake. For growth, we used mixed linear regression models to estimate the associations of hormones with weight, length, and head circumference z-scores at 6 and 12 months (World Health Organization standards). For neurodevelopment, we used linear regression models to measure the associations of hormones with Bayley Scales of Infant Development-III z-scores. We a priori controlled for maternal age, BMI, education, exclusive breastfeeding at 3 months, and gestational age at birth.

Results: We enrolled 99 mothers and measured milk hormones in 84 samples collected at 2 months and 75 samples collected at 5 months. Higher b-FGF was associated with higher weight z-scores at 6 months (adjusted mean difference [aMD] 0.33 z-scores per ug/mL; 95% CI 0.05, 0.61) and 12 months (aMD 0.31; 95% CI 0.04, 0.59), as well as higher length z-scores at 12 months (aMD 0.38; 95% CI 0.07, 0.69). Other growth hormones were not associated with growth outcomes at either 6 or 12 months. There were no significant associations between the intake of breast milk growth hormones and Bayley-III z-scores in this cohort.

Conclusion(s): Higher daily intake of b-FGF in breast milk was associated with increased length and weight at 6 and 12 months in this cohort, suggesting that this growth hormone may play a role in early growth.

Table 1. Population characteristics and growth hormone intake. Values are presented as either median (IQR) or n (%).
Values are presented as either median (IQR) or n (%). Abbreviations: BMI body mass index; MUAC mid-upper arm circumference; GA gestational age; SGA small for gestational age. *n=91,†n=87, ‡n=62,§n=99

Table 2. Adjusted associations of growth hormone intake with continuous child growth outcomes (beta coefficient + 95% CI).
Betas indicate the increase in z-score that is associated with 1-unit increase in growth hormone intake. Adjusted for birth z-score, maternal age, maternal BMI, gestational age, and breastfeeding exclusivity at 3 months. In the model, BDNF and bNGF are in ng/day. b-FGF, GDNF, VEGF, and Leptin are in µg/day. Significant associations in bold. BDNF = brain derived neurotrophic growth factor; b-FGF = beta fibroblast growth factor; GDNF = glial cell line-derived neurotrophic factor; bNGF = beta nerve growth factor; VEGF = vascular endothelial growth factor

Table 3. Adjusted associations of growth hormone intake with continuous Bayley-III z-scores at 24 months (beta coefficient + 95% CI).
Adjusted for gestational age, wealth index, mother age, and mother education. In the model, BDNF and bNGF are in ng/day. b-FGF, GDNF, VEGF, and Leptin are in µg/day. Significant associations in bold. BDNF = brain derived neurotrophic growth factor; b-FGF = beta fibroblast growth factor; GDNF = glial cell line-derived neurotrophic factor; bNGF = beta nerve growth factor; VEGF = vascular endothelial growth factor