They found that IL-18 levels were possibly associated with RA risk (OR = 1.07, 95% CI: 1.00 − 1.15) and that IL-18 levels appeared to be the genetic predisposition to seronegative RA risk (OR = 1.18, 95% CI: 1.02 − 1.36) [30]. This evidence concerns the gene IL18 and rheumatoid arthritis.