Table 1.

Characteristics of RA patients and healthy controls

	RA (n = 968)	HC (n = 1037)
Gender (%)
Male	202 (20.9)	220 (21.2)
Female	766 (79.1)	817 (78.8)
Age (years), (mean ± SD)	52.1 ± 13.4	49.7 ± 15.2
Age group (years), (%)
≤20	22 (1.3)	27 (2.6)
21–30	50 (5.2)	76 (7.3)
31–40	83 (8.7)	88 (8.5)
41–50	183 (19.1)	237 (22.9)
51–60	324 (33.8)	370 (35.7)
61–70	212 (22.1)	160 (15.4)
≥71	94 (9.8)	79 (7.6)
Ethnicity (%)
Han	913 (94.3)	967 (93.2)
Hui	18 (1.9)	20 (1.9)
Others	37 (3.8)	50 (4.8)

RA rheumatoid arthritis, HC healthy controls