北京地区汉族妇女绝经前后护骨素基因多态性与骨密度的关系

背景:原发性骨质疏松症是多基因遗传性疾病,但是调节骨量的基因需进一步研究。目的:探讨护骨素基因启动子区基因多态性与中国北京地区绝经前后妇女骨密度之间的关系。设计:前瞻性调查研究。单位:北京协和医院。对象:选择2002-07在北京协和医院健康体检的495名北京地区无亲缘关系的汉族妇女,其中绝经前妇女为306名,年龄20～39岁,绝经后妇女(指自然停经1年以上者)为189名,年龄50～84岁。所有受试对象均对检测项目知情同意。方法:①骨密度测量:应用双能X线骨密度测量方法,观察对象均采取仰卧位,采用骨密度仪测量其后前位第1～4腰椎及股骨近端,包括股骨颈、Ward’s三角和大转子部位的骨密度值。②基因分型:提取两组受试对象外周血DNA,初步确定护骨素基因分型。并取部分PCR产物送上海博亚有限公司测序,验证基因型,观察两组受试对象护骨素基因型的分布频率及其与骨密度的关系,并用Logistic回归作病因学进一步分析观察绝经后妇女护骨素基因多态性与骨质疏松的关系。主要观察指标:①两组受试对象护骨素基因型的分布频率,及其与骨密度的关系。②绝经后妇女护骨素基因多态性与骨质疏松的关系。结果:纳入受试对象495名,全部进入结果分析。①两组受试对象OPG基因型和等位基因分布频率无明显差异,两组总体基因型分布频率依次为163A→G位点,AA型为70.1%,AG型为26.9%,GG型为3.0%;245T→G位点TT型为71.3%,TG型为25.9%,GG型为2.8%。绝经前妇女在163A→G位点,AA组在L2-4、股骨颈、Ward’s三角和大转子的骨密度低于GG AG组,在245T→G位点,TT组与GG TG组相比各部位的骨密度也低,但均无统计学差异(P>0.05)。绝经后妇女163位点AG GG组在L2-4、股骨颈、Ward’s三角和大转子的骨密度均显著低于AA组(P<0.05);245位点TG GG组在股骨颈、Ward’s三角和大转子的骨密度显著低于TT组(P<0.05)。②绝经后妇女163位点AG GG组在L2-4、Ward’s三角是骨质疏松的危险因素(OR=2.045,2.956,P<0.05,95%可信限1.05-6.7),245位点TG GG组在L2-4、Ward’s三角、大转子是骨质疏松的危险因素(OR=2.059,2.859,2.123,P<0.05,95%可信限1.04-6.5)。结论:北京地区绝经后妇女护骨素基因启动子区的163和245位点为变异型G等位基因时,股骨颈、Ward’s三角和大转子的骨密度较低,变异型G等位基因与绝经后妇女骨密度降低相关。

Association between osteoprotegerin gene polymorphisms and bone mineral density of pre- and post-menopause Han women from Beijing areas

BACKGROUND: Osteoporosis is a genetic disease associated with many enes. To date, the genes that regulate bone mass are incompletely defined.OBJECTIVE: To investigate the relationship between polymorphisms of steoprotegerin (OPG) gene promoter with bone mineral density (BMD) in remenopausal and postmenopausal women.DESIGN: Prospective study.SETTING: Peking Union Medical College Hospital.PARTICIPANTS: In July 2002, 495 Han nationality women selected from Peking Union Medical College Hospital were non-related volunteers and gave their informed consent prior to the study, which included 306 premenopausal women aged 20-39 years, 189 postmenopausal women aged 50-84 years.METHODS: ① BMD measurement: BMD was measured at the Lumbar Spine and Femoral Neck, trochanter, Ward's triangle by dual-energy X-ray absorptiometry. ② Genotyping: Whole blood genome DNA was extracted by QIAGEN DNA extraction kit. The PCR product and the result of endonuclease digest were confirmed by sequencing (Bioasia Biotechnology,Shanghai, China). The impact of the polymorphisms on BMD was also investigated using multiple Logistic regression.MAIN OUTCOME MEASURES: ① Distribution of OPG genotypes and the relationship with BMD. ② Association between OPG polymorphisms and osteoporosis.RESULTS: All 495 subjects were involved in the final analysis. ① These polymorphisms were in Hardy-Weinberg equilibrium (χ2= 0.056 -0.222, P＞ 0.05). The frequencies of genotypes of these subjects were as follows: AA (70.1%), AG (26.9 %), GG (3.0 %) for 163A→G polymorphism; TT (71.3 %), TG (25.9 %), GG (2.8 %) for 245T→G polymorphism. BMD was lower in premenopausal women with GG +AG genotype than AA genotype for 163A→G polymorphism, so did GG+TG genotype than TT genotype for 245T→G polymorphism. But there was no significant difference. BMD was lower in postmenopausal women with AG+GG genotype than AA genotype for 163A→G polymorphism at Lumbar Spine 2-4, Femoral Neck, Ward's triangle and Trochanter (P ＜ 0.05). For 245T→G polymorphism, BMD of postmenopausal women with TG+GG genotype was lower at Femoral Neck,Ward's triangle and Trochanter than TT genotype (P ＜ 0.05). For 245T→G polymorphism, BMD of postmenopausal women with TG+GG genotype was lower at Femoral Neck, Ward's triangle, and Trochanter than TT genotype (P ＜ 0.05). ② Age, weight, height, years since menopause, and 163A→G/245T→G genotypes were sewed as covariates. AG+GG genotype was contributed to low BMD at Lumbar Spine 2-4 and Ward's triangle (OR =2.045, OR=2.956, P ＜ 0.05, 95% CI 1.05-6.7). TG+GG genotype was risk factor for osteoporosis at Lumbar Spine 2-4, Ward's triangle,and Trochanter (OR=2.059, OR=2.859, OR=2.123, P ＜ 0.05, 95% CI 1.04-6.5).CONCLUSION: BMD was lower in postmenopausal women with the variant G allele for 163A→G and 245T→G polymorphisms at Femoral Neck,Ward's triangle, and Trochanter. The variant allele G may associate with lower BMD in postmenopausal women.