Table 1.

Age and sex characteristics of study subjects.

Group	Gender	Age	Number of subjects
RA	Female	21–29	1
(N = 66)	(N = 51)	30–39	8
		40–49	9
		50–59	14
		60–69	16
		70–79	2
		>=80	1
	Male	50–59	6
	(N = 15)	60~69	9
Control	Female	20–29	5
(N = 60)	(N = 31)	30–39	2
		40–49	11
		50–59	10
		60–69	3
	Male	20–29	9
	(N = 29)	30–39	4
		40–49	6
		50–59	6
		>=60	4