Table 2.
OR with 95% CI of developing ACPA positive RA and ACPA negative RA for ever smokers compared with never smokers, by cumulative dose of smoking
| Pack years | ACPA positive RA | ACPA negative RA | ||||||
|---|---|---|---|---|---|---|---|---|
| ca/coa | OR (95% CI)b | OR (95% CI)c | p | ca/coa | OR (95% CI)b | OR (95% CI)c | p | |
| 0 | 730/2655 | 1.0 (reference) | 1.0 (reference) | 480/2655 | 1.0 (reference) | 1.0 (reference) | ||
| 1–2.5 | 160/551 | 1.0 (0.9–1.2) | 1.0 (0.8–1.2) | 0.9 | 101/551 | 1.0 (0.8–1.3) | 1.0 (0.8–1.3) | 0.8 |
| 2.5–5 | 127/362 | 1.2 (1.0–1.5) | 1.2 (1.0–1.6) | 0.05 | 66/362 | 1.0 (0.7–1.3) | 1.0 (0.8–1.3) | 0.9 |
| 5–7.5 | 102/261 | 1.4 (1.1–1.8) | 1.4 (1.1–1.8) | 0.007 | 70/261 | 1.4 (1.1–1.9) | 1.4 (1.1–2.0) | 0.007 |
| 7.5–10 | 117/257 | 1.7 (1.3–2.1) | 1.6 (1.3–2.0) | < 0.0001 | 62/257 | 1.3 (1.0–1.7) | 1.3 (1.0–1.7) | 0.1 |
| 10–12.5 | 97/215 | 1.7 (1.3–2.2) | 1.7 (1.3–2.2) | < 0.0001 | 41/215 | 1.0 (0.7–1.4) | 1.0 (0.7–1.4) | 0.8 |
| 12.5–15 | 126/214 | 2.2 (1.8–2.8) | 2.2 (1.7–2.8) | < 0.0001 | 46//214 | 1.1 (0.8–1.6) | 1.1 (0.8–1.6) | 0.4 |
| 15–17.5 | 98/159 | 2.4 (1.8–3.1) | 2.3 (1.8–3.1) | < 0.0001 | 48/159 | 1.6 (1.1–2.2) | 1.6 (1.1–2.2) | 0.009 |
| 17.5–20 | 122/182 | 2.6 (2.1–3.4) | 2.6 (2.0–3.3) | < 0.0001 | 51/182 | 1.5 (1.1–2.0) | 1.5 (1.1–2.0) | 0.03 |
| > 20 | 652/870 | 3.0 (2.7–3.5) | 3.0 (2.6–3.4) | < 0.0001 | 244/870 | 1.5 (1.2–1.7) | 1.5 (1.2–1.7) | 0.0002 |
| Trend < 0.0001 | Trend < 0.0001 | |||||||
aNumber of cases and controls
bAdjusted for age, gender, residential area, and study
cAdjusted for age, gender, residential area, study, ancestry, educational level, passive smoking, alcohol consumption, and body mass index at inclusion in the study