Table 2: Additional demographic information regarding RA patients.
| RA patient characteristics | |
| Mean duration of disease (standard error) | 13.3 years (1.56) |
| Smoking status | 29% current smokers, 37% past smokers, 34% never smoked |
| Seropositive (%) | 81.7% |
| Rheumatoid factor positive (%) | 71.6% |
| Anti-CCP antibody positive (%) | 66.1% |