Vitamin K and D Status in Patients with Knee Osteoarthritis: An Analytical Cross-sectional Study

Askari A, Ariya M, Davoodi SH, et al. · Mediterranean Journal of Rheumatology

Mean vitamin K and vitamin D were both lower in knee-osteoarthritis patients than in controls (P<0.001), with a vitamin K cut-off of 0.87 nmol/L discriminating cases; pain severity tracked disease status rather than either vitamin independently.

Population

150 patients with knee osteoarthritis and 300 people without it at an Iranian osteoarthritis clinic

Intervention

Serum vitamin K and vitamin D measured; no intervention

Comparator

Participants without knee osteoarthritis

Limitations

Cross-sectional at a single clinic, so reverse causation is live — reduced mobility changes diet and sun exposure; the reported odds ratios are hard to interpret as published; no menaquinone measurement.