Objective: The aim of this study was to explore whether polymorphisms in miR-146a, miR-499 and IRAK1 are associated with susceptibility to inflammatory arthritis.
Methods: Manual searches performed in the MEDLINE and EMBASE databases were used to identify published articles in which the roles of microRNA (miRNA) and IRAK1 polymorphisms in inflammatory arthritis were determined. A meta-analysis was conducted to investigate associations of the miR-146a rs2910164, miR-499 rs3746444, IRAK1 rs3027898 and IRAK1 rs1059703 polymorphisms with susceptibility to inflammatory arthritis.
Results: Nine studies containing 1224 patients and 1841 controls were included in the meta-analysis. The meta-analysis revealed no association between inflammatory arthritis and the rs2910164 C allele of miR-146a (odds ratio, OR = 0.974; 95 % confidence interval, CI = 0.810-1.091; p = 0.650). Stratification by ethnicity or disease type revealed no association between the miR-146a C allele and inflammatory arthritis in European, Middle Eastern or Asian patients with rheumatoid arthritis (RA) or juvenile idiopathic arthritis (JIA). However, the meta-analysis revealed an overall association between RA and the miR-499 rs374644 C (OR = 1.123, 95 % CI = 1.019-2.586, p = 0.041); stratification by ethnicity revealed a particular association in Middle Eastern populations (OR = 1.943, 95 % CI = 1.508-2.504, p = 2.7 × 10(-8)). The meta-analysis of IRAK1 polymorphisms revealed an association between inflammatory arthritis and the rs3027898 CC genotype (OR = 2.602, 95 % CI = 1.387-4.879, p = 0.003). An analysis using the homozygote contrast showed the same pattern for the rs3027898 CC genotype (OR = 2.472, 95 % CI = 1.300-4.700, p = 0.006). No association between inflammatory arthritis and the rs1059703 polymorphism was found.
Conclusion: This meta-analysis suggests that the miR-499 rs374644 and IRAKI rs3027898 polymorphisms are associated with susceptibility to inflammatory arthritis.