Association between osteoprotegerin gene polymorphisms and bone mineral density of pre- and post-menopause Han women from Beijing areas / 中国组织工程研究

ABSTRACT

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.