IL18 and rheumatoid arthritis: In Chinese population meta-analysis showed an association between RA and IL-18 rs1946518 A allele (OR=0.688,95%CI =0.532-0.889), as well as in studies with PCR-SSP method (OR=0.636, 95%CI =00.519-0.781) and small sample size (OR=0.559, 95%CI =0.438-0.715).