维生素D(Vitamin D)是调节骨矿物质代谢中重要的营养元素，其水平通常用血清总25(OH)D 浓度反映。维生素D 结合蛋白的多态性能够影响25(OH)D 的生物利用率。目前尚无统一的维生素D 不足或缺乏的诊断标准。慢性肾脏病患者维生素D 不足或缺乏的发生率高，且与慢性肾脏病的进展和预后相关。维生素D 不足或缺乏是慢性肾脏病患者发生肾功能下降、进展为终末期肾病、需肾脏替代治疗、肾性贫血、跌倒、心血管事件和死亡等不良预后的危险因素。补充营养性维生素D 能够纠正维生素D 不足或缺乏、降低甲状旁腺激素、减少蛋白尿、预防跌倒、改善血管舒缩功能、改善心功能，有助于改善患者的预后。

Vitamin D is an important nutrient involved in bone mineral metabolism. In most cases, serum total 25-hydroxyvitamin D (25[OH]D) level represents vitamin D content in the body. Genetic polymorphism in vitamin D binding protein affects the bioavailability of 25(OH)D. There is no consensus about the definition of vitamin D insufficiency and deficiency. Vitamin D insufficiency or deficiency is highly prevalent in patients with chronic kidney disease (CKD) and is closely related to the development and progression of CKD. Vitamin D insufficiency or deficiency is also the risk factor for the progression of renal insufficiency finally to end-stage renal disease necessary to be treated with renal replacement therapy, and also for the renal anemia, cardiovascular events and death in CKD patients. Supplement of vitamin D can increase serum total 25- hydroxyvitamin D concentration, decrease the elevated parathyroid hormone concentration, and improve proteinuria, risk of falls, cardiac and vascular function and prognosis in CKD patients.