Correlation of estrogen receptor alpha gene polymorphisms and bone mineral density in Chinese women with chronic periodontitis

Background Periodontitis and osteoporosis are one of the frequently encountered diseases in post-menopausal women. Estrogen receptors （ERs） regulated bone metabolism. To investigate the possible effect of ER-elpha （a） gene polymorphisms on bone mineral density （BMD） in pre- and post-menopausal Chinese women with chronic periodontitis （CP）, we provided sufficient quantitative information concerning the correlation between ER gene polymorphisms and BMD in periodontitis. Methods Sixty-five post-menopausal and eighty pre-menopausal CP women, and sixty post-menopausal healthy individuals were recruited in this study. Genomic DNA was extracted from oral mucosa swab sample of each subject by the Chelex-100 method. Determination of the ER-a polymorphisms was performed by polymerese chain reaction-restriction fragment length polymorphism （PCR-RFLP） technique with Xbal and Pvull enzyme. The index for periodontal examination includes clinical attachment loss （CAL） and probing pocket depth （PPD）. BMD was measured by dual-energy X-ray absorptiometry （DEXA）. Results There were no significant differences between the ER-α genotypes of Pvull and Xbal and BMD in post-menopausal and pre-menopausal CP patients, respectively （P 〉0.05）. However, there was association between pre- and post-menopausal CP patients at BMD of lumbar spine L2-L4 （P=0.027） and Ward＇s BMD （P=0.004）. Furthermore, the post-menopausal CP women who carried Pvull TT genotype presented significantly lower Ward＇s BMD than the pre-menopausal CP women （P=-0.007）, meanwhile, the post-menopausal CP women who carried Xbal AA genotype presented significantly lower spine L2-L4 BMD than the pre-menopausal CP women （P=0.003）. Conclusions ER-α gene polymorphisms may be a susceptible indicator for BMD variation of lumbar spine L2-L4 and Ward in Chinese pre- and post-menopausal women patients with CP.