Demographic and clinical features of study participants.
| Characteristic | 25(OH)D < 30 ng/ml, n = 59 | 25(OH)D < 20 ng/ml, n = 25 (of n = 59) | All Subjects, n = 87 |
|---|---|---|---|
| Sex, n (% female) | 48 (81.4) | 23 (92) | 70 (80.5) |
| Race, n (%) | |||
| White | 50 (84.8) | 18 (72.0) | 76 (87.4) |
| African American | 6 (10.2) | 5 (20) | 8 (9.2) |
| Asian | 2 (3.4) | 1 (4.0) | 2 (2.3) |
| American Indian/Alaska Native | 1 (1.6) | 1 (4.0) | 1 (1.2) |
| Ethnicity, n (% Hispanic) | 4 (6.8) | 1 (4.0) | 6 (6.9) |
| RF-positive, n (%) | 57 (98.3) | 25 (100) | 84 (97.7) |
| Anti-CCP–positive, n (%) | 34 (58.6) | 15 (60) | 49 (57.0) |
| Age, mean yrs (SD) | 52.9 (11.6) | 49.0 (11.2) | 55.2 (12.1) |
| Anti-CCP, mean U/ml (SD) | 49.4 (56.3) | 48.3 (58.8) | 53.4 (63.7) |
| RF, mean IU/ml (SD) | 81.1 (123.1) | 83.3 (119.3) | 138.2 (333.4) |
| DAS28, mean (SD) | 2.9 (1.5) | 3.2 (1.6) | 3.0 (1.5) |
| Years since RA diagnosis, mean (SD) | 12.3 (10.1) | 11.9 (9.6) | 13.9 (11.3) |
| ESR, mean mm/h (SD) | 13.4 (12.2) | 14.3 (9.2) | 15.3 (14.6) |
CCP: cyclic citrullinated peptide; RF: rheumatoid factor; ESR: erythrocyte sedimentation rate; DAS28: Disease Activity Score 28 joints; anti-CCP: anticyclic citrullinated peptide antibodies; 25(OH)D: 25-hydroxyvitamin D; RA: rheumatoid arthritis.