Akiba T, Ando R, Kurihara S, Heishi M, Tazawa H, Marumo F
Department of Internal Medicine, Tokyo Medical and Dental University, Japan.
Kidney Int Suppl. 1997 Nov;62:S69-71.
Polymorphism of the vitamin D receptor gene (VDR) has been linked to bone mineral density in twins, postmenopausal osteoporosis, and premenopausal woman. We examined the possibility that the bone mass in hemodialysis (HD) patients might be determined by VDR. The study consisted of 229 HD patients with a mean age of 53.3 years (range 21 to 83), who were dialyzed three times a week for an average of 8.65 (range 0.2 to 24) years. We determined their VDR using DNA of peripheral white blood cells by restriction enzyme BsmI and the polymerase chain reaction-restriction fragment length polymorphism method. Bone mineral content (BMC) was estimated at 1/3 of the radius using dual energy X-ray bone absorptiometry, and expressed in z-scores standardized by gender and age. Distributions of VDR in this hemodialysis population were BB (9.9%), Bb (13.1%), and bb (77.0%), showing no significant different from those in 105 healthy volunteers (BB, 7.6%; Bb, 13.3%; and bb, 79.0%). Multiple regression analysis revealed that gender, age, duration on HD, and serum osteocalcin are major determinants of BMC (r = 0.762, P < 0.001), while VDR and serum parathyroid hormone are not. In a subgroup with younger (< 65 years) patients dialyzed for less than 8.65 years, the z-score of BMC of patients with BB allele was less than those with Bb and bb allele (N = 77, P = 0.020). We conclude that vitamin D receptor polymorphism is not one of the main determinants of BMC of HD patients, though it might partially effect bone mass in a subgroup of younger HD patients with shorter HD histories. Further studies with longitudinal observation will be needed to confirm these possibilities.
维生素D受体基因（VDR）多态性与双胞胎的骨矿物质密度、绝经后骨质疏松症以及绝经前女性相关。我们研究了血液透析（HD）患者的骨量是否可能由VDR决定。该研究纳入了229例HD患者，平均年龄53.3岁（范围21至83岁），每周透析3次，平均透析8.65年（范围0.2至24年）。我们采用限制性内切酶BsmI和聚合酶链反应 - 限制性片段长度多态性方法，通过外周血白细胞DNA来确定其VDR。使用双能X线骨密度仪在桡骨1/3处估算骨矿物质含量（BMC），并以按性别和年龄标准化的z值表示。该血液透析人群中VDR的分布为BB（9.9%）、Bb（13.1%）和bb（77.0%），与105名健康志愿者的分布（BB，7.6%；Bb，13.3%；bb，79.0%）无显著差异。多元回归分析显示，性别、年龄、HD病程和血清骨钙素是BMC的主要决定因素（r = 0.762，P < 0.001），而VDR和血清甲状旁腺激素不是。在透析时间少于8.65年的年轻（< 65岁）患者亚组中，携带BB等位基因患者的BMC的z值低于携带Bb和bb等位基因的患者（N = 77，P = 0.020）。我们得出结论，维生素D受体多态性不是HD患者BMC的主要决定因素之一，尽管它可能在HD病史较短的年轻HD患者亚组中对骨量有部分影响。需要进一步进行纵向观察研究来证实这些可能性。
