Association between calcitonin receptor AluI gene polymorphism and bone mineral density: A meta-analysis

The association between calcitonin receptor (CTR) AluI gene polymorphism and bone mineral density (BMD) remains unclear. In order to elucidate this association, a meta-analysis was performed to provide a comprehensive assessment of the studies carried out to date. PubMed, the Cochrane Library, Web of Science and the China National Knowledge Infrastructure database were searched to identify eligible studies. The data were extracted independently by two authors using a standard form, the studies were meta-analyzed and disagreements were resolved through discussion. Fifteen eligible studies involving 3,093 females and 654 males were included for analysis. Overall, the male subjects with the CC genotype had non-statistically different lumbar spine and femoral neck BMD compared to subjects with the CT/TT and CT genotypes. The BMD of female subjects with the CC genotype was similar to that of patients with the CT or CT/TT genotypes. In Chinese male subjects, those with the CC genotype had almost the same BMD as those with the CT and CT/TT genotypes. The results also demonstrated that Chinese female subjects with the CC genotype had similar BMD at the lumbar spine and femoral neck to subjects with the CT and CT/TT genotypes. Furthermore, Southern Chinese subjects with CC genotypes did not have a different BMD at the lumbar spine and femoral neck compared to patients with CT and CT/TT genotypes. Notably, Northern Chinese subjects with the CC genotype had a higher BMD at the lumbar spine compared to subjects with CT/TT genotypes and a lower BMD at the femoral neck compared to subjects with CT/TT genotypes. Among Northern Chinese females, those with CC genotypes also had a higher BMD at the lumbar spine compared to those with CT/TT genotypes, while no difference was observed in the BMD of the lumbar spine and femoral neck between patients with CC and CT genotypes. In Southern Chinese females, no significant difference was found in the BMD at the lumbar spine and femoral neck between those with CC and those with CT or CT/TT genotypes. In conclusion, the AluI gene polymorphism may have an association with BMD in Northern Chinese subjects and the CC genotype may have a protective effect on spine BMD; however, the CC genotype may be a risk factor for low femoral neck BMD in Northern Chinese subjects. Further studies are required to fully investigate the potential association between AluI gene polymorphism and BMD.