RESUMO
<p><b>OBJECTIVE</b>To study serum insulin-like growth factor 1 (IGF-1) levels and their association with growth and development in infants aged 1-24 mouths.</p><p><b>METHODS</b>A total of 525 healthy infants (125 preterm, 400 term) were enrolled. Serum IGF-1 levels were measured using ELISA 1.5, 4, 6, 8, 12, 18 and 24 months after birth. The body weight and body length were simultaneously measured.</p><p><b>RESULTS</b>Serum IGF-1 levels were the lowest in preterm infants 1.5 months after birth (86+/-60 ng/mL). Thereafter, serum IGF-1 levels increased, and were significantly higher than those in term infants between 4 and 12 months after birth. Serum IGF-1 levels in term infants were the highest (116+/-52 ng/mL) 1.5 months after birth during their life of 12 months old. Thereafter, serum IGF-1 levels decreased and reached to a nadir (69+/-58 ng/mL) 8 months after birth. IGF-I levels were positively correlated with the weight and the height (SDS) in both preterm and term infants.</p><p><b>CONCLUSIONS</b>Serum IGF-1 levels are closely associated with growth and development in infants.</p>