Background: Increasing numbers of extremely low birth weight infants (ELBW, birth weight < 1,000 g) survive. We studied the impact of birth weight, gender, and catch-up growth on metabolic parameters in ELBW infants.
Children: Sixty-three ELBW children were investigated at a mean age of 5.8 years. Forty-eight showed catch-up growth.
Results: ELBW children who were small for gestational age were significantly shorter than those whose size was appropriate for their gestational age (height SDS: -1.1 [SD 0.8] vs -0.4 [0.9]; p < 0.001). This corresponded with significantly lower standard deviation scores for IGF-I (-1.1 [1.3] vs 0.1 [0.8]; p < 0.05) and IGFBP-3 (-0.7 [1.7] vs 0.4 [1.1]; p < 0.05). No differences were found regarding fasting insulin, glucose, HOMA and IGFBP-1. The catch-up group showed lower IGFBP-1 concentrations than the non-catch-up group. IGFBP-1 decreased in individuals who became more insulin resistant. No differences were found regarding mean IGF-1 and IGFBP-3 SDS. A gender-related pattern was found for weight development: girls demonstrated a normalization of BMI from the age of 2 years whereas boys remained at a mean BMI of -1.96 SDS. Corresponding to this, girls showed lower IGFBP-1 levels than boys.
Conclusion: Metabolic parameters in ELBW children are modulated by subsequent catch-up growth and sex-dependent weight development, resulting in measurable differences even in early childhood.