VDR and osteoarthritis, knee: The AA genotype was significantly more frequent among OA patients than controls and was associated with increased odds of OA (OR = 2.26, 95% CI = 1.21-4.23; p = 0.006).<h4>Conclusions</h4>The findings indicate that the VDR BsmI polymorphism is associated with knee osteoarthritis in the Kurdish population, whereas FokI, ApaI, and TaqI loci were non-polymorphic.