Interleukin-18 gene polymorphism and markers of subclinical atherosclerosis. the Cardiovascular Risk in Young Finns Study

Abstract

Background and aim. Interleukin-18 (IL-18) is a pro-atherosclerotic cytokine. We wanted to evaluate whether IL-18 gene polymorphism associates independently of risk factors, with early subclinical markers of atherosclerosis (intima-media thickness (IMT), coronary artery compliance (CAC), and flow-mediated dilatation (FMD)) in a population of young healthy Caucasian adults. Methods. This study was based on the on-going Cardiovascular Risk in Young Finns Study consisting of 2260 young adults, mean age being 31.7 (range 2439 years) (1247 women and 1013 men). Results. Five studied tagSNPs formed six major haplotypes, which accounted for 99.9% of all variation of the IL-18 gene. According to adjusted analysis of variance, the IL-18 gene polymorphism did not associate with subclinical atherosclerosis in the whole study population. However, one major haplotype associated differently among men and women with IMT (P 0.011). Male carriers of a major CCTgT haplotype (n 441) seemed to have a lower IMT when compared to the non-carriers (-0.016 mm, 95% confidence interval (CI) 0.028 to 0.004, P 0.014). Among women no significant associations were observed. Conclusions. Among all study subjects, the polymorphism of the IL-18 gene is not associated with subclinical markers of atherosclerosis. However, among men one major IL-18 haplotype seemed to associate with substantially lower IMT values.