Serum adiponectin levels, insulin resistance, and lipid profile in children born small for gestational age are affected by the severity of growth retardation at birth.

OBJECTIVE: Insulin resistance has been linked to intrauterine growth retardation (IUGR); adiponectin is a protein with insulin-sensitizing properties. This study was designed to test whether being born small for gestational age (SGA) has an effect on blood levels of adiponectin and leptin, insulin resistance parameters, and lipid profile in pre-puberty, taking into consideration the severity of IUGR.

METHODS: Serum levels of adiponectin, leptin, total cholesterol (t-CHOL), high density lipoprotein (HDL)-cholesterol, low density lipoprotein (LDL)-cholesterol, triglycerides, apolipoproteins A-1 (Apo A-1), Apo B and Apo E, lipoprotein(a) (Lp(a)), fasting glucose, and insulin (Ins), the homeostasis model assessment insulin resistance index (HOMA-IR) and anthropometric indices were evaluated in 70 children aged 6-8 years, born appropriate for gestational age (AGA; n = 35) and SGA (n = 35), matched for age, gender, height, and BMI. SGA children were divided into two subgroups according to the severity of IUGR: SGA<3rd percentile (n = 20), and SGA 3rd-10th percentile (n = 15). They were also subdivided in two subgroups, those with (n = 25) and those without (n = 10) catch-up growth, considering their actual height corrected for mid-parental height.

RESULTS: SGA children had higher Ins and HOMA-IR than AGA children (Ins, 42 +/- 23 vs 32 +/- 11 pmol/l; HOMA-IR, 1.30 +/- 0.8 vs 0.92 +/- 0.3; P<0.05). No significant difference in serum leptin was found between the SGA and the AGA groups but adiponectin showed a trend to be higher in SGA children (13.6 +/- 5.7 vs 10.8 +/- 5.9 microg/ml respectively). SGA children without catch-up growth had higher adiponectin (15.6 +/- 8.5 microg/ml, P<0.05) than AGA children. Among the SGA children, the subgroup <3rd percentile had higher Lp(a) than the subgroup 3rd-10th percentile (P<0.05). An independent positive correlation between adiponectin and Lp(a) was observed in SGA children (R = 0.59, P<0.01).

CONCLUSION: SGA children, although more insulin resistant, had similar or higher adiponectin levels than matched AGA children in pre-puberty. The severity of IUGR appears to affect their metabolic profile during childhood.