Differences in body composition and resting energy expenditure in childhood in preterm children born with very low birth weight.

Background: Rapid early ponderal growth is associated with adverse metabolic risks in young adults born at term.

Aim: To determine whether there are differences in body composition, resting energy expenditure (REE) and metabolic variables between preterm children born with very low birth weight (VLBW) either appropriate (AGA) or small (SGA) for gestational age and whether these differences are related to an early period of weight gain.

Methods: 67 VLBW preterm (40 AGA, 27 SGA). Body composition by DEXA, REE by indirect calorimetry and blood sampling at age 6.7 ± 0.5 years.

Results: VLBW SGA children were lighter, shorter, had a lower waist and hip circumference, HDL cholesterol and lipid oxidation rates than their AGA counterparts (adjusted for age, sex and BMI). Birth weight correlated negatively with total body and trunk fat mass. In a multivariate linear regression analysis, we found a positive association between weight gain in the first 3 months of life and total and trunk fat at age 6 years and a reciprocal association with REE at age 6 years. In contrast, the weight gain rate at 6-9 months of life was associated with higher REE and lipid oxidation rates at 6 years. A higher weight gain rate at 9-12 months was associated with a higher lean mass at 6 years.

Conclusion: An early fast-pace weight gain in VLBW infants may have detrimental consequences for metabolic health later on.