Abstract

Objective: To determine the circulating concentrations of adiponectin in preterm infants and examine the possible associations with anthropometric parameters, weight gain, leptin and insulin levels.

Design: Prospective study.

Setting: University Hospital Neonatal Care Unit.

Study population: 62 preterm [mean(SD) gestational age 32.0(2.1) weeks] and 15 fullterm infants, as reference group.

Interventions: Blood sampling at discharge [40.9 (14.8) days of life] in preterm infants and at a comparable postnatal age in fullterm infants. All infants were fed with the same commercial formula, but in 9 preterm infants the formula contained long-chain polyunsaturated fatty acids (LCPUFAs; arachidonic and docosahexaenoic).

Main outcome measures: Serum adiponectin, leptin and insulin levels in the entire study population. Associations of adiponectin levels were tested only in the preterm group.

Results: Serum adiponectin concentrations were lower in preterm [40.8(15.3) μg/ml] than fullterm infants [53.1(16.0) μg/ml, p<0.01]). However, the influence of prematurity on adiponectin levels did not remain significant after adjustment for body weight. In preterm infants, adiponectin levels were independently correlating with being born small for gestational age (SGA) (β=-0.35, p=0.01), weight gain (β =0.28, p=0.03), and feeding with the LCPUFA-supplemented formula (β=0.34, p=0.009). Serum adiponectin levels did not correlate with insulin or leptin levels. However, insulin levels tended to be higher in preterm than fullterm infants after adjustment for body weight (p=0.07).

Conclusions: In preterm infants at discharge, adiponectin levels are lower than fullterm infants probably due to decreased adiposity and they are influenced by being born SGA, weight gain and, possibly, by dietary LCPUFAs. The significance of the findings for the development of insulin or leptin resistance in children born prematurely needs to be further studied.