Mapping the Evidence on Human Milk Fortification and Cardiovascular Risk Factors and Outcomes among Low Birth Weight Infants: A Scoping Review

Abstract

Introduction: Preterm and low birth weight infants receiving a diet of human milk require fortification with protein, carbohydrates, vitamins, and minerals due to missed growth and nutrient accretion that would otherwise occur in utero. Although rapid catch-up growth improves anthropometric and neurodevelopmental indices, research has suggested that accelerated postnatal growth may be associated with poor long-term cardiometabolic outcomes.

Methods: We conducted a scoping review to map the evidence on human milk fortification and cardiometabolic risk factors and outcomes among low birth weight infants. We searched Ovid Medline, Ovid Embase, CINAHL, and Web of Science from inception to June 2021 and examined grey literature for relevant referenced articles. Studies were included if they were a primary study focused on fortified human milk and cardiometabolic risk factors or outcomes among low birth weight infants. A modified version of the Cochrane Collaboration Randomized Controlled Trial data collection form guided data collection. We conducted a narrative synthesis of the results structured around the Population, Concept, Context framework.

Results: We included 19 articles (14 randomized controlled trials, three quasi-randomized trials and two cohort studies) on cardiometabolic risk factors among 1,955 low birth weight infants who received fortified human milk. None of the included studies addressed long-term cardiometabolic outcomes. Body weight was the most examined risk factor in all included studies, with 13 studies observing benefit from human milk fortification. Two studies linked rapid growth with cardiometabolic risk factors.

Discussion: The focus across the 19 included studies was the anthropometric advantages of fortified HM among LBW infants.  A meta-analysis was not performed for this review, but if completed may yield a different inference.

Conclusion: Limited evidence is available regarding the long-term cardiometabolic outcomes among low birth weight infants who received fortified human milk. Existing literature is focused on the short-term anthropometric benefits of fortification post-hospital discharge. Yet, some reports have linked rapid early postnatal growth with the development of cardiometabolic risk factors later in life. Future studies should explore the long-term cardiometabolic outcomes among low birth weight infants with the goal of optimizing anthropometric and brain growth while minimizing long-term cardiometabolic risk.