基因多态性及环境因素与绝经后妇女骨密度的相关性研究

目的探讨雌激素受体(ER)基因多态性、维生素D受体(VDR)基因多态性以及环境因素与绝经后农村妇女的骨密度(BMD)的关系。方法随机抽取武汉农村绝经后妇女90名,汉族,年龄在45~65岁,应用问卷调查了解膳食摄入及户外活动情况;采用双能X线吸收仪(DXEA)测量腰椎及髋部的BMD;应用多聚酶联反应-限制性片断长度多态性(PCR-RFLP)检测ER和VDR的多态性。结果ER的Px单倍体型对各部位BMD均无显著性影响。VDR的BsmⅠ酶切位点多态性会影响腰椎的骨密度,Bb型的BMD比bb型要低,差异有显著性(P<0·05),但调整了年龄、体重、身高和膳食后,差异未见显著性。当联合研究ER和VDR基因多态性时,发现Px单倍体型同时伴有Bb的基因型的BMD最低,差异有显著性(P<0·05),调整年龄、体重、身高和膳食后,差异未见显著性。膳食钙、蛋白质、碳水化合物及能量与BMD简单相关;多元回归分析发现年龄(负相关)和体重(正相关)是绝经后妇女骨密度的最重要的预测因子,另外,与腰椎相关的因素还有绝经年龄及碳水化合物的摄入量;与股骨颈相关的因素还有绝经年龄。结论绝经后妇女BMD与ER的Px单倍体型未显示相关,与VDR的BsmI多态性可能相关,但环境因素会影响基因型与BMD的相关性。

Association of bone mineral density with gene polymorphisms and environmental factors in Chinese postmenopausal women

OBJECTIVE: To investigate the relationship between bone mineral density (BMD) and polymorphisms of the eatrogen receptor (ER) and vitamin D receptor (VDR) in relation to some environmental factors. METHODS: Ninety postmenopausal Chinese rural women of Han population, aged 45 to 65, were voluntarily enrolled in this study. We conducted BMD measurement of the lumber spine and hip by dual energy X-ray absorptiometry (DXEA) and performed a questionnaire survey of diet intake and outside activity. The polymorphisms of ER gene and VDR gene were determined using polymerase chain reaction restriction fragment length polymorphism ( PCR-RFLP). RESULTS: There is no significant influence of ER Px haplotype on BMD in Chinese women. VDR Bsm I polymorphisms was associated with BMD at the lumbar spine and the BMD in the Bb genotype was lower than in the bb genotype (P < 0.05), but the significant difference was weakened after adjusting for confounding factors such as age height weight activity diet and menopause age. Women with the ER Px haplotype and VDR B allele genotype had lowest BMD at lumber (P < 0.05), but the difference of BMD became not significant after adjusting for confounding factors such as age height weight activity diet and menopause age. Diet calcium, protein, carbohydrate and energy simply related to BMD. Stepwise multiple regression analysis showed that age and body weight were strong predictor of BMD in postmenopausal women. Other significant predictors were menopausal age and carbohydrate at lumber spine and menopausal age at femur neck. CONCLUSION: BMD was not associated with ER genotype but with VDR Bsm I polymorphism. Environmental factors influence the relationship between gene polymorphism and BMD.