Demographics and clinical characteristics of study participants
| Rheumatoid arthritis | Undifferentiated arthritis | Spondyloarthropathy | |
| N | 123 | 33 | 25 |
| Age years | 61 (52, 68) | 48 (40–53) | 46 (38.5–56) |
| Sex (F) | 71% | 88% | 52% |
| Anti-CCP ever positive | 80/123 (65%) | 2/33 (6%) | 1/25 (4%) |
| RF and CCP positive | 56% | 0% | 0% |
| HLADRB1 SE positive | 73/110 (66%) | 9/27 (33%) | 8/22 (36%) |
| DAS28ESR3var | 4.4 (3.2–5.2) | 2.7 (1.9–3.8) | 3.6 (2.9–4.5) |
| mHAQ | 0.5 (0.0, 0.9) | 0.2 (0–0.5) | 0.5 (0.2–1) |
| Smoking status | n=102 | n=29 | n=20 |
| Never smoker | 34% | 31% | 40% |
| Ex-smoker | 42% | 38% | 35% |
| Current smoker | 24% | 31% | 25% |
| LL37 ng/mL | 11.8 (5.9, 24.4) | 12.1 (4.1–16.0) | 11.9 (3.5–18.0) |
| Serum 25(OH)D mmol/L | 21.5 (14.4–31.3) | 17.3 (12.8–23.2) | 19.6 (10.9–30.8) |
| 25(OH)D deficient (%) | 60% | 82% | 64% |
| Vit D receptor polymorphism | |||
| Fokl | |||
| CC | 45/118 | 15/33 | 8/24 |
| CT | 53/118 | 10/33 | 11/24 |
| TT | 20/118 | 8/33 | 5/24 |
| Bsm1 | |||
| TT | 28/112 | 8/33 | 4/23 |
| CT | 51/112 | 14/33 | 9/23 |
| CC | 33/112 | 11/33 | 10/23 |
| Apa1 | |||
| TT | 26/117 | 5/29 | 6/24 |
| GT | 64/117 | 16/29 | 14/24 |
| GG | 27/117 | 8/29 | 4/24 |
| Taq1 | |||
| TT | 42/117 | 12/29 | 12/24 |
| TC | 59/117 | 15/29 | 11/24 |
| CC | 16/117 | 2/29 | 1/24 |
| Cdx1 | |||
| GG | 0/52 | 0/14 | 0/14 |
| GA | 52/52 | 14/14 | 14/14 |
| AA | 0/52 | 0/14 | 0/14 |
Categorical variables are reported as n/N measured (%), continuous variables are median (25%, 75%)±range.
CCP, cyclical citrullinated peptide; RF, rheumatoid factor; SE, shared epitope.