Impact of Early Weight Catch-Up on 6-Year Neurodevelopment and Overweight/Obesity in Children Born Small-for-Gestational-Age

Background/Objectives: Children born small-for-gestational-age (SGA) have varying growth patterns and developmental risks. In this study, we aimed to examine the relationship between weight-for-age z-scores (WAZ) at 2 years and neurodevelopmental and obesity outcomes at 6 years in children with SGA. Methods: We conducted a population-based cohort study using the National Health Insurance Service database of South Korea (N = 39,809). WAZ at 2 years was used to categorize children into four groups: G1 (WAZ < −1.28 [10th percentile], n = 9416), G2 (−1.28 ≤ WAZ < 0 [50th percentile], n = 20,322), G3 (0 ≤ WAZ < 1.04 [85th percentile], n = 8280), and G4 (1.04 ≤ WAZ, n = 1791). Neurodevelopment was assessed using the Korean Developmental Screening Test (K-DST). Overweight and obesity were defined using a body mass index-for-age z-score greater than the 85th and 95th percentiles, respectively, at 6 years of age. Adjusted odds ratios (aORs) and prevalence rates were estimated using Poisson and logistic regression models. Group-based comparisons were interpreted as exploratory analyses. Results: The prevalence of suboptimal neurodevelopment was highest in G1 (5.03%), followed by G4 (3.75%) at 6 years. A significantly increased risk of suboptimal K-DST scores was observed in G1 (aOR: 1.544; 95% confidence interval [CI]: 1.253–1.902), whereas a nonsignificant increase was found in G4 (aOR: 1.447; 95% CI: 0.938–2.234). At age 6, the prevalence of obesity was highest in G4 (19.60%), followed by G3 (7.11%), G2 (1.81%), and G1 (0.64%). The G4 group had the highest risk of overweight (aOR: 9.94) and obesity (aOR: 14.29) at 6 years. Conclusions: Weight status at age 2 in children with SGA was significantly associated with neurodevelopmental and obesity risks at age 6. These findings highlight the need for early weight monitoring and interventions to optimize long-term health in children with SGA.