North American Native population with RA, relatives, and controls.
| RA Probands | Affected Relatives | Unaffected FDR | Unaffected Distant Relatives | Unrelated Controls | |
|---|---|---|---|---|---|
| N | 266 | 6 | 165 | 42 | 176 |
| Female, % | 80 | 67 | 75 | 67 | 64 |
| Age at study, mean ± SD, yrs | 44.3 ± 13.8 | 30.5 ± 9.6 | 37.6 ± 12.2* | 26.8 ± 9.1* | 31.9 ± 12.4* |
| Age at RA onset, mean ± SD, yrs | 32.7 ± 13.8 | 15.0 + 4.5 | |||
| Age at RA diagnosis, yrs | 36.3 ± 14.3 | 21.2 ± 8.3 | |||
| RA disease duration, mean ± SD, yrs | 11.7 ± 9.3 | 11.5 ± 9.0 | |||
| RF-positive (%) | 223/255 (88) | 5/6 (83.3) | |||
| ANA-positive (%) | 154/201 (77) | 2/6 (33.3) | |||
| Receiving DMARD (%) | 196/210 (93) | 4/4 (100) |
ANA: antinuclear antibody; DMARD: disease modifying antirheumatic drug; FDR: first-degree relatives; RF: rheumatoid factor.
↵* p < 0.0001 compared with RA probands.