Rheumatoid arthritis (RA) is a systemic autoimmune disease affecting about 1% of world population. Three polymorphisms of Interleukin-1 receptor-associated kinase (IRAK1) gene, rs3027898, rs1059702 and rs1059703, are studied to associate with RA risk. However, the findings are inconclusive. Therefore, we performed a meta-analysis to derive a more precise estimation of the impact of the 3 polymorphisms on RA risk.
The strength of association between 3 polymorphisms and RA risk was assessed by calculating odds ratios (ORs) with the corresponding 95% confidence intervals (CIs).
Overall, for rs3027898 polymorphism, no association was observed in pooled analysis, but the stratified analysis suggested that rs3027898 CA genotype was associated with a reduced risk of RA in an Asian population (heterozygous model: OR = 0.79, 95% CI = 0.66-0.96, P = .018). Rs1059702 polymorphism was related with an increased RA risk (homozygous model: OR = 1.59, 95% CI = 1.19-2.13, P = .002, heterozygous model: OR = 1.49, 95% CI = 1.17-1.88, P = .001, and allele comparison model: OR = 1.35, 95% CI = 1.20-1.53, P < .001). Moreover, rs1059703 was also associated with an increased RA risk (dominant model: OR = 1.26, 95% CI = 1.07-1.49, P = .006), especially in Caucasian populations.
These results indicated that all 3 Interleukin-1 receptor-associated kinase (IRAK1) gene polymorphisms, rs3027898, rs1059702 and rs1059703 were related to RA risk.