Table 1 Characteristics of the study sample for association analyses
From: CYB5A polymorphism increases androgens and reduces risk of rheumatoid arthritis in women
Variable | Rheumatoid arthritis cases | Rheumatoid arthritis-free controls |
|---|---|---|
(n = 521) | (n = 321) | |
Sex, % female (n) | 83.3 (434) | 72.0 (231)* |
Age at inclusion, years (range) | 51.6 ± 11.2 (19 to 80) | 39.4 ± 15.1 (18 to 78)* |
Age of onset, years (range) | 40.7 ± 12.8 (2 to 75) | NA |
Duration of disease, years (range) | 10.8 ± 8.3 (1 to 45) | NA |
Rheumatoid factor, IU/mla | 149.8 ± 67.2 | ND |
Rheumatoid factor-positive, % (n) | 55.0 (279) | ND. |
Anti-CCP antibody, RU/mlb | 67.5 ± 53.7 | ND |
Anti-CCP positive, % (n)c | 78.6 (239) | ND |
C-reactive protein, mg/l | 19.6 ± 23.7 | ND |