Demographic characteristics of study populations
| Characteristics | control | RA | P-value |
| Number of subjects | 103 | 128 | |
| Sex, female/male | 63/37% | 73/27% | 0.57 |
| Age, mean ± SD | 50.2 ± 12 yr | 52.8 ± 11 yr | 0.18 |
| Ethnicity | 0.62 | ||
| African American | 28.2% | 37.5% | |
| White | 42.7% | 39.8% | |
| Hispanic | 22.3% | 18.0% | |
| Asian | 6.8% | 4.7% |
| Characteristics | control | RA | P-value |
| Number of subjects | 103 | 128 | |
| Sex, female/male | 63/37% | 73/27% | 0.57 |
| Age, mean ± SD | 50.2 ± 12 yr | 52.8 ± 11 yr | 0.18 |
| Ethnicity | 0.62 | ||
| African American | 28.2% | 37.5% | |
| White | 42.7% | 39.8% | |
| Hispanic | 22.3% | 18.0% | |
| Asian | 6.8% | 4.7% |