Table 5.

OR with 95% CI of developing ACPA positive and negative RA for smokers compared with never-smokers, by number of years since stopping smoking and cumulative dose of smoking

ACPA positive RA
Pack years of smoking Years since stopping smoking	0			< 10		10–20		> 20
Never smokers	730/2655	1.0 (reference)
Current smokers			146/411	1.2 (1.0–1.4)	227/325	2.5 (2.1–3.1)	382/518	2.8 (2.4–3.3)
< 10 years			114/254	1.5 (1.2–1.9)	109/149	2.7 (2.1–3.6)	185/181	4.0 (3.2–5.1)
10–20 years			92/250	1.4 (1.1–1.8)	81/188	1.7 (1.3–2.6)	63/114	2.3 (1.7–3.2)
> 20 years			133/466	1.2 (0.9–1.4)	46/158	1.2 (0.9–1.8)	23/57	1.7 (1.0–2.8)

ACPA negative RA
Pack years of smoking Years since stopping smoking	0			< 10		10–20		> 20
Never smokers	480/2655	1.0 (reference)
Current smokers			81/411	1.2 (0.9–1.6)	89/325	1.5 (1.2–1.9)	143/518	1.5 (1.1–1.8)
< 10 years			50/254	1.2 (0.9–1.7)	46/149	1.7 (1.1–2.3)	57/181	1.6 (1.2–2.3)
10–20 years			56/250	1.3 (1.0–1.8)	37/188	1.1 (0.7–1.6)	34/114	1.5 (1.0–2.3)
> 20 years			104/466	1.2 (0.9–1.5)	22/158	0.8 (0.5–1.2)	10/57	0.9 (0.5–1.7)

Adjusted for age, gender, residential area, study, ancestry, educational level, passive smoking, alcohol consumption, and body mass index at inclusion in the study