The risk of metabolic consequences from rpaid weight gain and catch-up growth in the first two years of life: a systematic review

Abstract

Infants who experience faltering growth, are born preterm, or small for gestational age, often experience rapid weight gain in infancy. Poor growth during infancy is associated with children who are lighter and shorter later in life and have a lower Intelligence Quotient (IQ) and poorer neurocognitive outcomes. Catch-up growth in infants born small for gestational age is known to prevent gastrointestinal dysfunction, developmental delay, and improves survival rates in infants born preterm. In recent years, more attention has been given to the longer term risks of rapid weight gain in infancy, with studies showing increased rates of overweight and obesity and other metabolic outcomes later in life in infants who experienced rapid weight gain. The aim of this systematic review was to build on existing evidence and provide a more detailed analysis of the relationship between not only rapid weight gain and overweight status in adulthood, but also between changes in weight gain in infancy and adult Body Mass Index (BMI), with weight gain experienced at various time points in the first two years of life, across term, preterm and small for gestational age infants. This review aims to assist clinicians to better determine how to approach the management of infants with poor growth requiring weight gain. Electronic bibliographic databases and trial registers were searched for all study types investigating infancy weight gain experienced from 0-2 years of age and metabolic outcomes experienced after 18 years of age, with no date or language restrictions. Two independent reviewers conducted the literature search, title, abstract and full text screen, assessed methodological quality using the QUIPS (Quality in Prognosis Studies) tool, and extracted the data using bespoke excel spreadsheets. Synthesis involved pooling for statistical meta-analysis with a random effects model where possible, and a narrative analysis with figures and tables where meta-analysis was not possible. There were 23 studies with 24,531 subjects identified. Of the 23 studies, 16 reported a significant association between infancy weight gain and BMI or overweight in adulthood. The risk of overweight in adulthood from rapid weight gain experienced at any interval from 0-2 years was significant (pooled OR = 2.59, 95% CI 1.16, 5.75, p = 0.02; low certainty). The risk of overweight in adulthood from rapid weight gain experienced at the interval from 0-6 months was not significant (pooled OR 1.90, 95% CI 0.86, 4.19, p = 0.11; moderate certainty). Of 18 studies exploring the relationship between infancy weight gain and adult BMI, 12 reported a significant positive association. Overall, the weight of evidence supports a positive association between rapid weight gain or change in weight-for-age z-score or standard deviation score in infancy and BMI in adulthood. This review demonstrates a risk of overweight in adulthood from rapid weight gain experienced in the first two years of life, which is stronger when experienced later in infancy. It is prudent to suggest that healthcare workers focus on modifiable determinants of rapid weight gain, such as promoting breastfeeding, are mindful of unnecessary weight gain in infancy, particularly after the neonatal stage, and educate families on the risks of rapid weight gain in infancy.