Relative risk of having rheumatoid nodules in ever smokers compared with never smokers by number of smoked cigarette packs, stratified as rheumatoid factor positive or negative
| Packs | RF positive patients (68 men, 66 women) | RF negative patients (30 men, 35 women) | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cases | Controls | OR | 95% CI | Cases | Controls | OR | 95% CI | ||||||||||
| CI, confidence interval; OR, odds ratio; ref, reference; RF, rheumatoid factor. | |||||||||||||||||
| 0 | 4 | 37 | 1.0 (ref) | 5 | 23 | 1.0 (ref) | |||||||||||
| 1 to 5000 | 15 | 11 | 12.9 | 3.5 to 47.3 | 5 | 13 | 1.7 | 0.4 to 7.2 | |||||||||
| 5001 to 9500 | 14 | 20 | 6.8 | 1.9 to 23.9 | 3 | 8 | 1.4 | 0.2 to 8.1 | |||||||||
| 9501 to 37 000 | 15 | 18 | 8.3 | 2.4 to 29.6 | 1 | 7 | 0.6 | 0.1 to 6.7 | |||||||||
| Total | 48 | 86 | 14 | 51 | |||||||||||||