Abstract
Early postnatal growth following extremely preterm birth may have long-term effects on growth, eating behaviours and health. Background/Objectives: To determine whether growth to age two years is conditional on growth in the NICU, a conditional growth analysis was performed in a cohort of 330 extremely low-birthweight (ELBW; birthweight < 1000 g) participants in the ProVIDe trial who were followed-up at 2 years corrected age (CA); Methods: We used z-score change for weight, length and head circumference from 36 weeks post-menstrual age to 2 years CA as the end-point-adjusted for birth z-score and z-score change from birth to 36 weeks. Growth and body composition were assessed using bioimpedance analysis. Relationships between eating behaviours and body mass index (BMI) at 2 years CA and growth were assessed using a Child Eating Behaviour Questionnaire (CEBQ) completed by parents at 2 years CA; Results: Growth, or change in z-score, from 36 weeks PMA was conditional upon growth in the NICU, with slower neonatal growth associated with faster early childhood growth (weight: R(2) = 0.27, ß-coefficient -0.81 (95% CI: -0.96, -0.66), p < 0.0001; length: R(2) = 0.28, ß-coefficient -0.64 (95% CI: -0.76, -0.51), p < 0.0001; head circumference: R(2) = 0.18, ß-coefficient -0.61 (95% CI: -0.76, -0.46), p < 0.0001). Fat-free mass index, adjusted for confounding factors, was positively correlated with z-score change from NICU discharge to 2 years CA for weight, but not length (weight: R(2) = 0.50, ß-coefficient = 0.87 (95% CI: 0.56, 1.18), p < 0.0001; length: R(2) = 0.32, ß-coefficient = 0.01 (95% CI: -0.40, 0.42), p = 0.95). At 2 years CA, CEBQ scores for enjoyment were significantly higher and satiety and slowness significantly lower in children with a BMI ≥ 90th percentile than in children with a BMI ≤ 10th percentile or between the 10th-90th percentile.; Conclusions: Growth from NICU discharge to 2 years CA is conditional upon growth in the NICU, with slower NICU growth linked to faster early childhood growth, and weight z-score changes positively correlated with fat-free mass index. At age 2, children with a BMI ≥ 90th percentile have significantly different eating behaviour assessments by caregivers compared to children with a BMI ≤ 10th percentile or between the 10th-90th percentile; further RCTs are needed to confirm links between nutrition factors and growth outcomes in ELBW infants.