Table 3 Relative odds (ORs), with 95% confidence intervals (CIs), of rheumatoid factor positive rheumatoid arthritis between tertiles* of anti-CCP antibodies and of ratios of antibodies to citrulline/arginine-containing (C/A) (I) and (II) C-telopeptides

Antibody	Tertile*	No. of cases	No. of controls	Univariate odds OR (95% CI)	Multifactorial model† OR (95% CI)
Anti-CCP (unit)	Lower	15	83	1.00	1.00
	Medium	18	88	1.84 (0.78 to 4.34)	1.91 (0.76 to 4.80)
	Higher	56	90	7.25 (3.06 to 17.20)	6.12 (2.44 to 15.35)
C/A (I) (ratio)	Lower	15	71	1.00	1.00
	Medium	26	80	2.41 (0.95 to 6.10)	2.03 (0.79 to 5.23)
	Higher	41	88	3.78 (1.47 to 9.68)	2.54 (0.98 to 6.60)
C/A (II) (ratio)	Lower	25	86	1.00	1.00
	Medium	22	88	0.98 (0.48 to 2.00)	1.13 (0.49 to 2.60)
	Higher	42	86	2.44 (1.11 to 5.37)	2.31 (0.93 to 5.75)

*The tertiles are based on the distributions among controls; †adjusted for two other antibodies.