| |
Whole group
|
Never smokers
|
Ever smokers
|
|---|
| |
Number of cases/controls
|
OR (95% CI)
a
|
OR (95% CI)
a
|
OR (95% CI)
a
|
|---|
|
Whole group
|
1,666/920
|
1.03 (0.87-1.21)
|
1.39 (1.04-1.85)
|
0.83 (0.67-1.04)
|
|
Stratification by serological status
| | |
|
Seronegative
| | | | |
|
RF-
|
476/920
|
1.20 (0.96-1.51)
|
1.82 (1.24-2.69)
|
0.96 (0.73-1.28)
|
|
ACPA-
|
585/920
|
1.03 (0.83-1.27)
|
1.42 (0.98-2.05)
|
0.77 (0.58-1.04)
|
|
RF-/ACPA-
|
361/920
|
1.14 (0.89-1.47)
|
1.67 (1.10-2.55)
|
0.80 (0.56-1.13)
|
|
RF-/ACPA+b
|
105/920
|
1.54 (0.99-2.38)
|
3.07 (1.37-6.89)
|
1.06 (0.57-1.99)
|
|
Seropositive
| | | | |
|
RF+
|
925/920
|
1.00 (0.83-1.20)
|
1.26 (0.89-1.78)
|
0.86 (0.68-1.10)
|
|
ACPA+
|
916/920
|
1.08 (0.89-1.30)
|
1.55 (1.08-2.23)
|
0.88 (0.69-1.13)
|
|
RF+/ACPA-c
|
172/920
|
0.83 (0.59-1.17)
|
0.96 (0.53-1.74)
|
0.74 (0.47-1.17)
|
|
RF+/ACPA+
|
744/920
|
1.06 (0.87-1.29)
|
1.42 (0.97-2.10)
|
0.90 (0.70-1.16)
|
- aRisk was calculated as odds ratios (ORs) with 95% confidence intervals (CIs) adjusted for age, sex, and geographic location by using logistic regression. bIn the ACPA+ group, 20% of never smokers and 10% of smokers were RF-: OR 2.07 (1.36 to 3.14), P = 0.0005. cIn the RF+ group, 24% of never smokers and 17% of smokers were ACPA-: OR 1.58 (1.11 to 2.25), P = 0.01. ACPA, anti-citrullinated protein antibody; EIRA, Epidemiological Investigation of Rheumatoid Arthritis; MBL, mannan-binding lectin; RF, rheumatoid factor.
