Postmenopausal Women: A Meta-Analysis

Osteoporosis is a progressive bone disease that is characterised by a decrease in bone mass and density and that leads to an increased risk of fracture. In osteoporosis, the bone mineral density (BMD) is reduced, bone microarchitecture deteriorates, and the amount and variety of proteins in bone are altered. Both environmental and genetic factors are the etiology of osteoporosis. In addition, family and twin studies show that osteoporosis is a multi-gene regulation, strong hereditary diseases. Osteoporosis and osteoporotic fractures had brought serious harms to families and societies due to its high incidence, mortality, and medical costs.

The early identification of a person who is at risk to develop osteoporotic fractures is therefore of major clinical interest. Morrison’s study have shown that vitamin D receptor has been associated with Bone Mineral Density (BMD), which is the major determinant of osteoporosis risk. Since then, many factors about the relationship between gene polymorphism, BMD and fracture were intensively investigated, such as typecollagen gene, calcitonin receptor gene, low-density lipoprotein receptor related protein gene and cannabinoid receptor genes. However, vitamin D receptor gene is the most studied and controversial gene.

Vitamin D receptor gene is located on chromosome 12, longer than 100 kb. Through the genome of a single nucleotide polymorphism frequency analysis, the vitamin D receptor gene polymorphism should be more than 100 kinds. We know vitamin D receptor gene polymorphisms mainly related to four single nucleotide polymorphisms (BsmI, TaqI, ApaI and FokI) from recent study. Fang et al. performed a meta-analysis relating BsmI or TaqI polymorphisms of the VDR gene with Osteoporosis risk. They searched published studies from 1996 to September 2005 through PubMed and evaluated the genetic effect of the BsmI and TaqI polymorphism of VDR on fracture risk and found out that there was no relationship between the VDR BsmI or TaqI polymorphism and fracture risk.