Baseline demographic characteristics of cases of rheumatoid arthritis (RA) and controls in MyEIRA, by ethnicity.

RF: rheumatoid factor, ACPA: anti-citrullinated proteins antibody, SE: shared epitope.*patients and controls carrying one or two alleles of shared epitope were classified as SE-positive.The percentages calculated in each characteristic category were based on the number of available data.

RF（类风湿因子）、ACPA（抗环瓜氨酸蛋白抗体）、SE（共享表位）。携带一个或两个共享表位等位基因的患者和对照被归类为SE阳性。每个特征类别的百分比均基于可用数据的数量计算得出。