The contributions of plasma IGF-I, IGFBP-3 and leptin to growth in extremely premature infants during the first two years.

We determined the contributions of IGF-I, IGFBP-3 and leptin to growth in -extremely premature infants over the first two years. Weight (Wt), crown-to heel length (CHL), plasma IGF-I, IGFBP-3 and leptin were measured in infants (gestation 24-33 wk) at birth (n 54), expected date of delivery (EDD) and 6, 12 and 24 mo post-EDD (n 29). Area under the curve (AUC) for hormone levels was calculated over 4 periods: birth-EDD, EDD-200 d, EDD- 350 d and EDD-700 d. IGFBP-3, but not IGF-I or leptin, on day 1 correlated with birth Wt SD scores (SDS) (r 0.46, p 0.002) and CHL SDS (r 0.41, p 0.01). Wt SDS at EDD correlated with AUC IGF-I, IGFBP-3 and leptin (birth-EDD), but leptin was the best predictor in multiple regression(r 0.65, p 0.0001). Wt at EDD 700 d correlated with AUC leptin (EDD-700 d) (r 0.62, p 0.002). CHL SDS at EDD correlated with AUC IGFBP-3 and leptin (birth-EDD), but IGFBP-3 was the best predictor (r 0.55, p 0.0001). CHL at EDD 700 d correlated with AUC IGF-I and IGFBP-3 (EDD-700 d), but IGFBP-3 was the best predictor (r 0.47, p 0.01). Wt and CHL at birth were associated with IGFBP-3 levels in these infants. Wt at EDD and EDD 700 d was predicted by concurrent leptin output while linear growth at EDD and EDD 700 d was predicted by IGFBP-3 output. (Pediatr Res 61: 99-104, 2007)