Table 2.
Characteristics of the participants
| Characteristics | HC, n==198 | RA, n = 405 | p |
|---|---|---|---|
| Demographic | |||
| Age, years, mean (SD) | 60.4 (10c.4) | 59.4 (10.3) | 0.275 |
| Disease duration, years, median [IQR] | NA | 5.5[1.5;13.0] | NA |
| BMI, Kg/m2, mean (SD) | 22.8 (3.6) | 22.1 (3.4) | 0.031 |
| Female, n (%) | 146 (73.7) | 317 (78.3) | 0.256 |
| Menopause status of female, n (%) | < 0.001* | ||
| Post-menopause, age > 45 | 104 (71.2) | 186 (58.7) | |
| Early menopause, age ≤ 45 | 25 (17.1) | 38 (12.0) | |
| Lifestyle | |||
| Smoking, ever or current, yes, n (%) | 17 (8.6) | 36 (8.9) | 0.937 |
| Drinking, ever or current, yes, n (%) | 18 (9.1) | 18 (4.4) | 0.035 |
| Medical history | |||
| Diabetes mellitus | 35 (17.7) | 47 (11.6) | 0.055 |
| Hypertension | 75 (37.9) | 77 (19.0) | < 0.001 |
| Coronary heart disease | 20 (10.1) | 20 (4.9) | 0.027 |
| Hyperuricemia | 15 (7.6) | 43 (10.6) | 0.297 |
| Dyslipidemia | 58 (29.3) | 56 (13.8) | < 0.001 |
| Femoral neck necrosis | 1 (0.5) | 8 (2.0) | 0.268 |
| Osteoporotic fracture | 0 | 20 (4.9) | NA |
| Anti-osteoporotic medication | 6 (3.0) | 29 (7.2) | 0.641 |
| Laboratory | |||
| Serum calcium level, mmol /L, mean (SD) | 2.4 (0.2) | 2.3 (0.1) | < 0.001 |
| Serum phosphate level, mmol /L, mean (SD) | 1.9 (8.1) | 1.2 (0.4) | 0.272 |
| Serum creatinine level, μmol /L, mean (SD) | 67.2 (32.9) | 62.6 (20.5) | 0.086 |
| Serum Uric acid level, μmol /L, mean (SD) | 327.9 (101.2) | 314.1 (103.9) | 0.146 |
| Serum 25(OH)D3 level, nmol /L, mean (SD) | 65.6 (22.1) | 76.7 (32.9) | 0.006 |
| Vitamin D insufficiency, yes, n (%) | 65 (32.8) | 145 (35.8) | 0.046* |
| Hypovitaminosis D, yes, n (%) | 43 (21.7) | 118 (29.1) | 0.046* |
*: p for trend with Cochran-Armitage test; HC Healthy controls, RA Rheumatoid arthritis, hypovitaminosis D Serum 25(OH)D3 < 50 nmol/L, VitD3 deficiency Serum 25(OH)D3 < 75 nmol/L