CDX2 and osteoporosis: In addition, the examination of 36 studies on VDR BsmI, 15 studies on VDR FokI, and three studies on VDR Cdx2 by Zhang et al. [25] indicated that the VDR BsmI and VDR FokI polymorphisms were associated with an increased the risk of developing osteoporosis in overall and Asians, while the VDR Cdx2 polymorphism may be not associated with osteoporosis risk.