Numbers of pre-RA cases and matched controls reporting heavy cigarette smoking (CS 30+/day) at baseline by relevant categories and odds ratios (ORs) with 95% confidence intervals (95% CIs) for developing ACR+ rheumatoid arthritis
| Pre-RA cases | Respective matched controls | |||||
|---|---|---|---|---|---|---|
| Categories | Number | CS 30+/day (%) | Number | CS 30+/day (%) | OR | 95% CI |
| *No association of CS 30+/day with pre-RA RF+ (p=0.99). | ||||||
| †Conversion of RF− at baseline to RF+ after clinical onset of RA. | ||||||
| Pre-RA RF+ | 12 | 2 (17)* | 48 | 11 (23)* | 0.7 | 0.1 to 3.5 |
| Pre-RA RF− | 42 | 11 (26) | 168 | 8 (5) | 7.1 | 2.6 to 19.1 |
| Entry and post-RA RF− | 15 | 4 (27) | 60 | 1 (2) | 21.5 | 2.2 to 210.6 |
| Conversion of pre-RA RF− to RF+† | 27 | 7 (26) | 108 | 7 (6) | 5.1 | 1.6 to 16.0 |