Table 3.
Odds of developing rheumatoid arthritis, stratified by serologic subset, according to HLA SE status and different categories of smokers compared with never smokersa
| 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) | |
| HLA SE negative | ||||||||
| Never smoker | 161/592 | 1.0 (reference) | 18/592 | 1.0 (reference) | 42/592 | 1.0 (reference) | 86/592 | 1.0 (reference) |
| Past smoker | 142/501 | 1.0 (0.7–1.3) | 12/501 | 1.0 (0.4–1.8) | 43/501 | 1.1 (0.7–1.7) | 117/501 | 1.6 (1.2–2.2) |
| Current smoker | 89/263 | 1.2 (0.9–1.6) | 11/263 | 1.3 (0.6–2.8) | 48/263 | 2.4 (1.5–3.7) | 88/263 | 2.3 (1.6–3.2) |
| HLA SE heterozygote | ||||||||
| Never smoker | 151/521 | 1.0 (reference) | 59/521 | 1.0 (reference) | 49/521 | 1.0 (reference) | 265/521 | 1.0 (reference) |
| Past smoker | 125/464 | 0.9 (0.7–1.1) | 58/464 | 1.2 (0.8–1.8) | 58/464 | 1.6 (0.9–2.0) | 369/464 | 1.6 (1.3–2.0) |
| Current smoker | 95/272 | 1.1 (0.8–1.5) | 46/272 | 1.5 (0.97–2.3) | 49/272 | 1.7 (1.1–2.7) | 336/272 | 2.4 (1.9–2.9) |
| HLA SE homozygote | ||||||||
| Never smoker | 35/137 | 1.0 (reference) | 38/137 | 1.0 (reference) | 15/137 | 1.0 (reference) | 177/137 | 1.0 (reference) |
| Past smoker | 35/92 | 1.3 (0.9–2.6) | 29/92 | 1.3 (0.7–2.2) | 11/92 | 1.1 (0.5–2.5) | 238/92 | 2.2 (1.6–3.1) |
| Current smoker | 16/60 | 1.0 (0.6–2.0) | 31/60 | 1.9 (1.04–3.4) | 12/60 | 1.8 (0.8–3.9) | 235/60 | 3.2 (2.2–4.6) |
a
All analyses were adjusted for age, sex, residential area, and ancestry. SE = shared epitope; 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.