TABLE 3.
Serum concentrations of 25(OH)D and PTH in association with knee osteoarthritis progression between baseline and follow-up visits in 418 participants with knee osteoarthritis1
| Baseline value | Progress, n (%) | No progress, n (%) | OR (95% CI)2 | OR (95% CI)3 |
| Serum 25(OH)D | ||||
| High (≥15 μg/L) | 44 (12.5) | 308 (87.5) | 1.0 | 1.0 |
| Low (<15 μg/L) | 15 (22.7) | 51 (77.3) | 2.4 (1.2, 4.8) | 2.2 (1.0, 4.6) |
| Serum PTH | ||||
| Low (<73 pg/mL) | 44 (13.3) | 286 (86.7) | 1.0 | 1.0 |
| High (≥73 pg/mL) | 15 (17.0) | 73 (83.0) | 1.2 (0.6, 2.4) | 1.8 (0.8, 4.4) |
| Interactions | 0.18 | 0.18 | ||
| 25(OH)D high, PTH low | 37 (12.7) | 253 (87.3) | 1.0 | 1.0 |
| 25(OH)D low, PTH low | 7 (18.0) | 32 (82.0) | 1.5 (0.6, 3.7) | 1.5 (0.6, 3.9) |
| 25(OH)D high, PTH high | 7 (11.5) | 54 (88.5) | 0.8 (0.3, 1.9) | 0.8 (0.3, 1.9) |
| 25(OH)D low, PTH high | 8 (29.6) | 19 (70.4) | 3.3 (1.2, 8.6) | 3.4 (1.2, 9.2) |
Knee osteoarthritis progression is defined as any increase in joint space narrowing score between baseline and follow-up visits, including within-grade changes. OA, osteoarthritis PTH, parathyroid hormone; 25(OH)D, 25-hydroxyvitamin D.
Logistic regression model for serum 25(OH)D was adjusted for age (continuous) and study site. Logistic regression models for serum PTH and the joint effect for 25(OH)D and PTH were adjusted for age (continuous), BMI (continuous), season (months), and study site.
Logistic regression models were adjusted for age (continuous), sex, race (non-Hispanic white vs. others), BMI (continuous), physical activity (meeting the guidelines yes vs. no), season (months), and study site.