IPW adjustment with propensity scores was adopted to control for potential confounding factors such as age, sex, positivity of RF and anti-CCP antibody, dose of prednisolone, dose of methotrexate, use of bDMARDs or tsDMARDs, and DAS28-CRP in the RA cohorts, and age and sex in the HC cohorts between from Tsukuba and Karuizawa. The gene discussed is CRP; the disease is rheumatoid arthritis.