Presented at the Neonatal Society 2017 Summer Meeting.
Li Y1, Liu X2, Modi N3,4, Uthaya S3,4
1 National Perinatal Epidemiology Unit, Oxford, UK
2 Imperial College London, UK
3 Chelsea and Westminster NHSFT, London, UK
4 Section of Neonatal Medicine, Imperial College London, UK
Background: The relationship between breast milk (BM) and body composition in early infancy has been established to some extent in infants born at term, with formula fed infants having higher fat free mass and lower fat mass. Little is known about the impact of BM on body composition in preterm infants. The aim of this study was to investigate the impact of BM intake on body composition at term in very preterm infants.
Methods: This was a pre-planned secondary analysis of the Nutritional Evaluation and Optimisation in Neonates study, a 2-by-2 factorial, double-blind, multicentre randomised controlled trial of preterm parenteral nutrition (PN). Recruitment was between July 2010 and July 2013, with final follow-up in October 2013 in four NHS hospitals. Infants born at <31 weeks of gestation were eligible for inclusion; infants with life-threatening congenital abnormalities and those unable to receive trial PN within 24 hours of birth were excluded. One hundred and thirty-three infants survived and underwent whole-body magnetic resonance imaging at term (between 37 and 44 weeks postmenstrual age). Exposure to breast milk was defined as follows; from birth until 34 weeks postmenstrual age, exclusive enteral diet of breast milk (BM) (proportion of breast milk=100% milk; predominant enteral diet of BM (proportion of BM 51-99%); predominant enteral diet of formula (proportion of BM ≤ 50%). Multivariable regression was used to examine differences in feed exposure and outcomes, adjusted for covariates including baseline characteristics, age at imaging, total nutrient intake before 34 weeks of postmenstrual age, and level of care comparing the predominantly BM and predominantly formula milk groups against the exclusively BM group as the reference. Outcomes: Non-adipose tissue mass (Non-ATM), ATM, and ATM as a percentage of body weight (% ATM).
Results: Fifty-six infants received an exclusive BM diet, 39 predominantly breast milk and 38 predominantly formula. In comparison with the exclusively BM group, predominantly formula fed infants weighed 283.6g (95%CI: 121.6, 445.6) more, had 257.4g (95%CI: 139.1-375.7) more non-ATM and had a greater positive weight Z-score change between birth and term. There were no significant differences in weight, non-ATM and change in weight Z-score between the exclusively and predominantly BM groups. In comparison with the exclusively BM group no significant differences were observed in ATM and % ATM in the predominantly BM and predominantly formula fed groups respectively. Further adjustment for length did not alter the conclusions.
Conclusion: The finding of higher weight and non-ATM mass at term in the predominantly formula fed group compared with the exclusively BM fed group may reflect lower protein intake in the latter. Whether these differences persist into childhood and adult life, and relate to functional outcomes, are important research questions.
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Uthaya S, Liu X, Babalis D, et al. The American Journal of Clinical Nutrition. 2016;103(6):1443-1452