Low-birth-weight, but not catch-up growth, correlates with insulin resistance and resistin level in SGA infants at 12 months.

Objective: To investigate the insulin resistance status in SGA infants at 12 months and its relationship with auxological and metabolic parameters.

Methods: One group of 45 SGA and one of 50 appropriate for gestational age infants were followed from birth to the end of the first year of life. At 12 months, skinfold thickness, waist circumference, and blood levels of glucose, insulin, adiponectin, leptin, resistin, visfatin, retinol-binding protein 4, IGFs, lipids profile were determined, and the HOMA-IR index was calculated.

Results: The SGAs had increased insulin (5.2 ± 2.7 versus 2.9 ± 2.4 μIU/ml, p = 0.012) and HOMA-IR (1.09 ± 0.9 versus 0.59 ± 0.55, p = 0.016). In multiple regression, insulin resistance indices were independently correlated with low-birth-weight (β = -2.92, p = 0.015 for insulin, β = -2.98, p = 0.011 for HOMA-IR) but not with catch-up growth in either height or weight or any other metabolic parameter. Resistin was higher in the SGAs (5.1 ± 2.1 versus 3.9 ± 2.1 ng/ml, p = 0.03) and independently correlated with low-birth-weight but not insulin resistance. Resistin was negatively correlated with total cholesterol (R = -0.33, p = 0.007) and positively with lipoprotein(a) (R = 0.49, p = 0.001).

Conclusion: Low-birth-weight, but not catch-up growth or adiposity tissue hormones, was correlated with insulin resistance at 12 months in non-obese SGA infants. The higher resistin in SGA infants and its correlation with total cholesterol and lipoprotein(a) need further clarification.