Participants in the TwinGene-study with and without rheumatoid arthritis (RA)
| Without RA during follow-up from inclusion into the study | Prevalent RA at inclusion | Future incident RA during follow-up from inclusion into the study | |||||
|---|---|---|---|---|---|---|---|
| All | ACPA− | ACPA+ | ACPA− | ACPA+ | ACPA− | ACPA+ | |
| Overall number of individuals | 12 590 (100%) | 12 172 (96.7%) | 226 (1.8%) | 53 (0.4%) | 103 (0.8%) | 15 (0.1%) | 21 (0.2%) |
| Age at inclusion, year | 64 (60–70) | 64 (60–70) | 65 (61–71) | 67 (61–72) | 65 (60–70) | 70 (66–73) | 67 (60–69) |
| Female sex | 6865 (55%) | 6587 (54%) | 138 (61%) | 41 (77%) | 74 (72%) | 11 (73%) | 14 (67%) |
| Ever-smoking | 6254 (50%) | 6028 (50%) | 123 (55%) | 26 (49%) | 56 (54%) | 8 (57%) | 13 (62%) |
| CRP mg/L | 1.7 (0.7–3.5) | 1.7 (0.7–3.4) | 2.2 (1.0–4.4) | 3.8 (1.1–7.5) | 5.9 (2.0–13) | 3.4 (2.4–7.7) | 1.8 (0.8–5.3) |
| HLA-SE | 5612 (52%) | 5377 (51%) | 114 (60%) | 24 (59%) | 80 (90%) | 5 (38%) | 12 (80%) |
| Median follow-up, months, from inclusion to end of year 2009 | 37 (31–49) | 37 (31–49) | 37 (31–49) | 39 (35–49) | 38 (34–39) | 47 (43–55) | 45 (31–50) |
Values are given as number (%) or median (first to third quartile). There was a lack of data for smoking habits, occurrence of HLA-SE and CRP for 69/1788/601, respectively. Anti-CCP2 test was used for measuring ACPA that denotes negative (−) or positive (+) status. Blood was donated at one time point during year 2004 to 2008 at the time of inclusion into the study.
ACPA, Anti-citrullinated protein antibodies; CRP, C reactive protein; HLA-SE, human leucocyte antigen (DRB1) shared epitope alleles.