Table 2.
Odds of developing rheumatoid arthritis, stratified by serologic subset, according to different categories of smokers compared with never smokers, in total and by cumulative dose of smokinga
| Anti‐CCP2−, RF− | Anti‐CCP2+, RF− | Anti‐CCP2−, RF+ | Anti‐CCP2+, RF+ | |||||
|---|---|---|---|---|---|---|---|---|
| No. cases/no. controlsb | OR (95% CI) | No. cases/no. controlsb | OR (95% CI) | No. cases/no. controlsb | OR (95% CI) | No. cases/no. controlsb | OR (95% CI) | |
| Total | ||||||||
| Never smoker | 367/2,655 | 1.0 (reference) | 133/2,655 | 1.0 (reference) | 111/2,655 | 1.0 (reference) | 594/2,655 | 1.0 (reference) |
| Past smoker | 330/1,909 | 1.1 (0.9–1.4) | 109/1,909 | 1.2 (0.98–1.6) | 116/1,909 | 1.3 (1.02–1.8) | 774/1,909 | 1.8 (1.6–2.1) |
| Current smoker | 218/1,319 | 1.1 (0.9–1.3) | 89/1,319 | 1.3 (1.004–1.7) | 109/1,319 | 1.8 (1.3–2.3) | 695/1,319 | 2.4 (2.1–2.7) |
| <10 pack‐years | ||||||||
| Never smoker | 367/2,655 | 1.0 (reference) | 133/2,655 | 1.0 (reference) | 111/2,655 | 1.0 (reference) | 594/2,655 | 1.0 (reference) |
| Past smoker | 179/1,062 | 1.1 (0.9–1.4) | 58/1,062 | 1.1 (0.8–1.5) | 62/1,062 | 1.2 (0.9–1.7) | 320/1,062 | 1.2 (1.001–1.5) |
| Current smoker | 68/476 | 1.1 (0.8–1.5) | 28/476 | 1.0 (0.7–1.3) | 28/476 | 1.2 (0.8–1.8) | 148/476 | 1.3 (1.1–1.5) |
| 10–20 pack‐years | ||||||||
| Never smoker | 367/2,655 | 1.0 (reference) | 133/2,655 | 1.0 (reference) | 111/2,655 | 1.0 (reference) | 594/2,655 | 1.0 (reference) |
| Past smoker | 79/495 | 1.0 (0.7–1.2) | 30/495 | 1.3 (0.9–2.0) | 25/495 | 1.2 (0.8–1.9) | 205/495 | 1.9 (1.6–2.3) |
| Current smoker | 52/325 | 1.1 (0.8–1.5) | 26/325 | 1.6 (1.04–2.5) | 37/325 | 2.4 (1.6–3.6) | 201/325 | 2.7 (2.2–3.3) |
| >20 pack‐years | ||||||||
| Never smoker | 367/2,655 | 1.0 (reference) | 133/2,655 | 1.0 (reference) | 111/2,655 | 1.0 (reference) | 594/2,655 | 1.0 (reference) |
| Past smoker | 72/352 | 1.2 (0.9–1.6) | 21/352 | 1.5 (0.9–2.4) | 29/352 | 1.9 (1.3–2.7) | 249/352 | 3.1 (2.6–3.7) |
| Current smoker | 98/518 | 1.2 (0.9–1.5) | 35/518 | 1.6 (1.05–2.4) | 44/518 | 2.0 (1.2–3.1) | 346/518 | 3.6 (2.9–4.4) |
a
All analyses were adjusted for age, sex, residential area, and ancestry. Anti‐CCP2 = anti–cyclic citrullinated peptide 2; RF = rheumatoid factor; OR = odds ratio; 95% CI = 95% confidence interval.
b
Values are the number of exposed cases and controls.