Association between serum 25-hydroxyvitamin D and change in hip pain over 2.4 years, as assessed by the WOMAC questionnaire
| Univariate | Multivariate model 1 | Multivariate model 2 | ||||
|---|---|---|---|---|---|---|
| β coefficient (95% CI) (n=765) | p Value | β coefficient (95% CI) (n=765) | p Value | β coefficient (95% CI) (n=602) | p Value | |
| Vitamin D (continuous measure) | ||||||
| Change in total hip WOMAC score | −0.002 (−0.02 to 0.02) | 0.83 | 0.0003 (−0.02 to 0.02) | 0.97 | 0.01 (−0.01 to 0.04) | 0.27 |
| Change in hip pain when…. | ||||||
| Walking on a flat surface | −0.001 (−0.006 to 0.004) | 0.70 | −0.001 (−0.006 to 0.004) | 0.82 | 0.002 (−0.004 to 0.007) | 0.58 |
| Going up and down stairs | −0.001 (−0.006 to 0.004) | 0.61 | 0.0006 (−0.004 to 0.006) | 0.81 | 0.003 (−0.003 to 0.008) | 0.31 |
| At night while in bed | 0.0001 (−0.005 to 0.005) | 0.98 | 0.0002 (−0.005 to 0.006) | 0.95 | 0.003 (−0.003 to 0.009) | 0.33 |
| Sitting or lying | 0.001 (−0.004 to 0.005) | 0.80 | 0.001 (−0.004 to 0.005) | 0.70 | 0.004 (−0.001 to 0.009) | 0.11 |
| Standing upright | −0.001 (−0.005 to 0.004) | 0.80 | −0.001 (−0.005 to 0.004) | 0.76 | 0.002 (−0.003 to 0.007) | 0.42 |
| Vitamin D (<25 nmol/l compared with ≥25 nmol/l) | ||||||
| Change in total hip WOMAC score | 2.19 (−0.26 to 4.64) | 0.08 | 2.20 (−0.29 to 4.69) | 0.083 | 2.31 (−0.69 to 5.3) | 0.13 |
| Change in hip pain when…. | ||||||
| Walking on a flat surface | 0.42 (−0.26 to 1.10) | 0.22 | 0.42 (−0.27 to 1.11) | 0.23 | 0.54 (−0.29 to 1.38) | 0.20 |
| Going up and down stairs | 0.52 (−0.05 to 1.09) | 0.07 | 0.48 (−0.09 to 1.05) | 0.09 | 0.52 (−0.17 to 1.21) | 0.14 |
| At night while in bed | 0.48 (−0.13 to 1.09) | 0.12 | 0.50 (−0.12 to 1.12) | 0.12 | 0.52 (−0.14 to 1.19) | 0.12 |
| Sitting or lying | 0.30 (−0.03 to 0.63) | 0.07 | 0.31 (−0.05 to 0.66) | 0.09 | 0.17 (−0.23 to 0.57) | 0.40 |
| Standing upright | 0.47 (−0.16 to 1.10) | 0.14 | 0.49 (−0.13 to 1.11) | 0.12 | 0.47 (–0.30 to 1.25) | 0.23 |
Model 1: Adjusted for age, sex BMI and season (summer, autumn / winter, spring).
Model 2: Further adjusted for leg strength, radiographic hip osteoarthritis (present/absent), use of pain medication at baseline, and baseline WOMAC score (same scale—for example, baseline total hip WOMAC score for change in total hip WOMAC score).
Change in WOMAC score is from phase 2 to phase 3 (2.4 years).
BMI, body mass index; WOMAC, Western Ontario and McMaster University Osteoarthritis Index.