No relative increase in intra-abdominal adipose tissue in healthy unstressed preterm infants at term

Background: Preterm infants may be at risk for altered adiposity, a known risk factor for unfavorable metabolic and cardiovascular outcomes. Objectives: The aim was to compare body composition (total body fat mass (FM), subcutaneous and intra-abdominal adipose tissue (AT)) between infants born preterm and at term.Methods: We conducted an observational, cross-sectional study that involved 50 infants born preterm free from major co-morbidities and 34 term healthy breastfed infants. Anthropometric measurements, body composition (total body FM, subcutaneous and intraabdominal AT) were assessed at 40-42 weeks postconceptional age for preterm infants and within 15 days of birth for term infants. Total body FM was assessed by an air displacement plethysmography system and subcutaneous abdominal and intra-abdominal AT were assessed by magnetic resonance imaging using a commercially available software program.Results: Compared to term infants, mean (SD) total body FM (g) (636.7 (247) vs. 418.4 (253), p < 0.0001) and mean (SD) subcutaneous abdominal AT (g) (123 (36) vs. 98.9 (22), p < 0.001) were significantly higher in preterm infants but mean (SD) fat-free mass (g) (2,530 (420) vs. 2,965 (389), p < 0.0001) and mean (SD) intra-abdominal AT (10.9 (5.2) vs. 18.2 (13.2), p = 0.001) were significantly lower.Conclusions: In the absence of severe illness during the hospital stay, prematurity, although associated with increased total body FM, does not appear to be associated with a relative increase in intra-abdominal AT compared to term infants.