Background: At present, literature regarding postnatal growth in small for gestational age (SGA) subjects and its correlation with growth factor levels is still controversial. A relation between IGF1 and IGFBP3 levels at birth and weight and length catch up growth has been demonstrated. In the first months of life a rapid weight catch-up growth has also been associated to an increase of leptin, basal insulin and insulin resistance.
Objective and hypotheses: To evaluate the correlation between weight and length growth, growth factor levels and insulin resistance index (HOMA-IR) in the first year of life of 30 subjects born SGA.
Method: A total of 30 subjects born at term were studied: 15 with a birthweight < 2 S.D. and a normal length; 15 with both length and weight < 2 S.D. for gestational age. Anthropometrical parameters and blood sampling for the evaluation of glucose, insulin, IGF1, IGFBP3 and leptin were obtained at birth (T0), 1st (T1), 3rd (T2), 6th (T3) and 12th (T4) month of life. Insulin resistance was calculated by Homa-IR.
Results: Length and weight catch-up growth was observed in all infants within the 6th month of life. A significant increase (P<0.05) in the growth factors evaluated and Homa-IR values was found at 12 months when compared with values at birth. IGF1, insulin and HOMA-IR values correlated positively with the increase in weight at 1st month (P< 0.05), while leptin values were significantly correlated only at 6th month of life (P<0.05). IGF1 and IGFBP3 values correlated positively with length catch up growth only at 1st month of life (P<0.05).
Conclusion: Our data confirm the important role of IGF1, insulin and leptin in rapid weight catch-up growth in the first months of life; the significant increase of early insulin resistance may explain later metabolic abnormalities that characterize SGA subjects. Less clear remains the role of IGF1 and IGFBP3 on length catch-up growth.
01 Oct 2015 - 03 Oct 2015