Early Development of Adiposity and Insulin Resistance after Catch-Up Weight Gain in Small-for-Gestational-Age Children

TLDR

Low birth weight followed by rapid postnatal weight gain is linked to long‑term risks of central obesity and insulin resistance. The study aims to determine when rapid weight gain after low birth weight leads to central adiposity and insulin resistance, and to identify mechanisms that could guide early preventive interventions. The authors followed 51 children (29 SGA, 22 AGA) from birth to age 4, measuring body composition with DXA and insulin sensitivity at ages 2, 3, and 4 years. By age 4, SGA children had accumulated more abdominal fat, higher insulin resistance, and increased neutrophil counts than AGA peers, with early postnatal weight gain (0–2 yr) driving these changes.

Abstract

Low birth weight followed by rapid postnatal weight gain is associated with long-term risks for central obesity and insulin resistance. However, the timing of these changes is unclear.This was a longitudinal cohort study in low birth weight (SGA; birth weight < -2 sd; n = 29) and normal birth weight (AGA; n = 22) children from Barcelona.Body composition, by dual-energy x-ray absorptiometry scan, and insulin sensitivity, assessed longitudinally at ages 2, 3, and 4 yr, were measured.Mean height, weight, and body mass index at ages 2, 3, and 4 yr were not different between SGA and AGA children. At age 2 yr, SGA children had similar body composition but were more insulin sensitive than AGA children and had lower serum IGF-I levels and lower neutrophil counts. Between ages 2 and 4 yr, despite similar gains in weight and body mass index, SGA children gained more abdominal fat and body adiposity and less lean mass than AGA children; by age 4 yr, SGA children had greater adiposity, insulin resistance, and higher neutrophil counts than AGA children (P = 0.01-0.0004). In SGA children, total and abdominal fat mass at 4 yr was more closely related to rate of weight gain between 0 and 2 yr (P = 0.002-0.0003) than between 2 and 4 yr (P = 0.04-0.1).Consequent to catch-up weight gain between birth and 2 yr, SGA children showed a dramatic transition toward central adiposity and insulin resistance between ages 2 and 4 yr. Understanding the mechanisms underlying this predisposition to adverse future health could lead to specific preventive interventions during early childhood.