Cohort characteristic for the discovery cohort (11 366 cases and 15 489 controls)
| Collection | Cases | Controls | ||||
|---|---|---|---|---|---|---|
| All | Women (%) | ACPA+ | ACPA− | All | Women (%) | |
| UK | 3768 | 2772 (73.57) | 2360 | 954 | 8051 | 3504 (43.52) |
| Swedish EIRA | 2759 | 1943 (70.42) | 960 | 562 | 1939 | 1415 (72.98) |
| USA | 2534 | 1908 (75.30) | 1801 | 2726 | 2133 | 1383 (64.84) |
| Dutch | 647 | 428 (66.15) | 329 | 301 | 2004 | 844 (42.12) |
| Swedish UMEA | 852 | 594 (69.72) | 524 | 242 | 963 | 659 (68.43) |
| Spanish | 806 | 599 (74.32) | 396 | 216 | 399 | 260 (65.16) |
| Total | 11 366 | 8244 (72.53) | 6370 | 2868 | 15 489 | 8065 (52.07) |
Rheumatoid arthritis (RA) cases and controls were assembled from a number of different studies from six centres across five countries. RA cases were classified as anti-citrullinated protein antibody (ACPA) positive (ACPA+) or ACPA negative (ACPA−). Swedish EIRA, Swedish Epidemiological Investigation of Rheumatoid Arthritis; Swedish Umea, Swedish.