Plasma IL-1 Receptor Antagonist Concentration Has an Inverse Association With Birth Weight in Prepubertal Children

CONTEXT: Birth size has an impact on later cardiometabolic risk that is strongly related to low-grade inflammation. OBJECTIVE: To evaluate plasma interleukin-1 receptor antagonist (IL-1ra) concentrations in relation to birth size and cardiometabolic and inflammatory markers in prepubertal children. DESIGN: A cohort study. Anthropometric data were recorded. Fasting blood samples were collected for plasma analyses of IL-1ra, alanine transaminase, total cholesterol, high- and low-density lipoprotein cholesterols, triglyceride, glucose, and serum analyses of 25-hydroxyvitamin D [25(OH)D] and high-sensitivity C-reactive protein (hs-CRP) concentrations. PARTICIPANTS: Forty-nine large for gestational age (LGA), 56 appropriate for gestational age, and 23 small for gestational age (SGA) children at 5 to 8 years of age were examined. MAIN OUTCOME MEASURES: Differences in IL-1ra concentrations among the birth-size groups and associations between IL-1ra and other metabolic markers were assessed. RESULTS: Body mass index (BMI) standard deviation score (SDS)-adjusted plasma IL-1ra concentrations were highest in the SGA- and lowest in the LGA-born children (P = 0.015). Age- and sex-adjusted IL-1ra concentrations had strongest associations with BMI SDS (P < 0.001) and hs-CRP (P < 0.001, also when further adjusted for BMI SDS). CONCLUSIONS: Prepubertal children born SGA had the highest and those born LGA the lowest IL-1ra concentrations in this study cohort. Most associations found between IL-1ra and the studied metabolic parameters were weight related, but the association with hs-CRP remained strong after adjustment for BMI. It seems that at prepuberty, SGA children have a stronger inflammatory state than LGA children and may thus be at a greater risk for later metabolic disturbances.