Table 1.

Incidence rate of type 2 diabetes (T2D; per 1000 person-yrs) in rheumatoid arthritis (RA) group and non-RA group, by age.

Age in 1998		Number at Risk	Person-yrs at Risk^*	Case Number	Incidence Rate (95% CI)	Rate Ratio (95% CI)
Men
20–39	RA	260	1628.34	11	6.76 (2.78, 10.74)	1.84 (1.03, 3.30)
20–39	non-RA	163942	1909620.24	7018	3.68 (3.59, 3.76)
40–59	RA	472	2783.21	79	28.38 (22.21, 34.56)	1.92 (1.55, 2.38)
40–59	non-RA	96883	1064652.16	15707	14.75 (14.52, 14.98)
≥ 60	RA	398	2301.44	59	25.64 (19.18, 32.09)	1.11 (0.86, 1.43)
≥ 60	non-RA	38180	384756.81	8874	23.06 (22.59, 23.54)
Overall	RA	1130	6713.00	149	22.2^§ (18.67, 25.72)	1.68 (1.53, 1.84)
Overall	non-RA	299005	3359029.21	31599	9.41^§ (9.30, 9.51)
Women
20–39	RA	687	4068.60	21	5.16 (2.96, 7.36)	2.52 (1.66, 3.80)
20–39	non-RA	166482	1952158.93	4011	2.05 (1.99, 2.12)
40–59	RA	1372	8557.87	161	18.81 (15.93, 21.69)	1.45 (1.24, 1.69)
40–59	non-RA	95590	1065802.85	13796	12.94 (12.73, 13.16)
≥ 60	RA	650	4158.44	114	27.41 (22.45, 32.38)	1.03 (0.87, 1.22)
≥ 60	non-RA	35420	354049.17	9404	26.56 (26.03, 27.09)
Overall	RA	2709	16784.91	296	17.64^§ (15.64, 19.6)	1.46 (1.39, 1.54)
Overall	non-RA	297492	3372010.95	27211	8.07^§ (7.97, 8.17)

↵* Per 1000 person-years. The accumulation of person-time for RA patient started from the diagnosis of RA, while that for the non-RA group started from January 1998, until either the diagnosis of T2D or the observation being censored by the end of 2009.
↵§ Age-standardized incidence rate.