Rheumatoid arthritis (RA) is a complex polygenic inflammatory disease associated with accelerated atherosclerosis. IL-6 is a key mediator of inflammation in RA. A recent study showed an association between IL6-174 G/C gene polymorphism and cardiovascular (CV) disease in UK individuals with RA. To confirm this association we assessed the influence of three IL6 gene polymorphisms in the risk of CV disease in a large series of patients with RA.
We studied 1250 Spanish patients with RA. Besides genotyping the traditional single nucleotide polymorphism (SNP) promoter -174G/C (rs1800795), we assessed another two SNPs (rs2069827 and rs2069840) located in the IL6 gene that were selected by SNP-tagging.
Two-hundred and twenty (17.6%) of the 1250 patients experienced CV events. No significant differences in the genotype, allele and haplotype frequencies between RA patients with and without CV events were observed.
Our results do not confirm in a Spanish population the association of IL6 gene with CV disease in RA previously reported in the UK.