In the subgroup analysis by ethnicity, there had been decreased relationships between RA risk and IL-21 rs6822844 polymorphism in both Asians (T-allele versus G-allele: OR = 0.48, 95% CI = 0.37–0.63, Pheterogeneity=0.115, P<0.001; TG versus GG: OR = 0.38, 95% CI = 0.28–0.53, Pheterogeneity=0.231, P<0.001 and TT+TG versus GG: OR = 0.42, 95% CI = 0.31–0.56, Pheterogeneity=0.148, P<0.001, Figure 4) and Caucasians (TG versus GG: OR = 0.86, 95% CI = 0.75–0.99, Pheterogeneity=0.392, P=0.035 and TT+TG versus GG: OR = 0.88, 95% CI = 0.78–0.99, Pheterogeneity=0.556, P=0.041, Figure 4 and Table 3). The gene discussed is IL21; the disease is rheumatoid arthritis.