Division of Gastroenterology, University of California-San Diego, CA, USA.
Semin Liver Dis. 2011 Nov;31(4):387-98. doi: 10.1055/s-0031-1297927. Epub 2011 Dec 21.
According to the Institute of Medicine, the risk of clinically significant vitamin D deficiency increases at 25-hydroxyvitamin D levels below 20 ng/mL. By this standard, most cirrhotic hepatitis C virus- (HCV-) positive patients and many noncirrhotic patients are vitamin D-deficient. The high prevalence of vitamin D deficiency among HCV patients is a cause for concern for several specific reasons. Classic studies established the importance of vitamin D and calcium in maintaining bone. Vitamin D's beneficial effects on bone are likely to be vital for HCV-infected patients because these individuals have a high prevalence of low bone mineral density. Many pharmaceutical agents reduce bone density and exposure to these drugs may increase bone disease in HCV-positive patients. Bone loss occurs following liver transplantation and bone density is often low in patients with HIV/HCV co-infection who are on combination antiretroviral therapy. Some evidence suggests that ribavirin reduces bone density, underscoring the special need to monitor vitamin D in patients receiving HCV treatment and to prescribe supplements, as appropriate. In addition to its role in calcium metabolism, vitamin D is also an immune modulator that reduces inflammation while enhancing protective immune responses. Higher vitamin D levels are associated with less liver fibrosis and less inflammation in HCV patients. Recent studies show that low vitamin D levels are associated with treatment failure among HCV-infected patients receiving pegylated-interferon and ribavirin. If confirmed, these findings will provide an additional reason to ensure adequate levels of vitamin D. Information about how to monitor vitamin D status and how to use vitamin D supplements most effectively in HCV-infected patients is provided.
根据医学研究所的数据，当 25-羟维生素 D 水平低于 20 纳克/毫升时，出现临床显著维生素 D 缺乏的风险会增加。按照这个标准，大多数丙型肝炎病毒（HCV）阳性的肝硬化患者和许多非肝硬化患者都存在维生素 D 缺乏。HCV 患者中维生素 D 缺乏的高患病率有几个具体的原因值得关注。经典研究确立了维生素 D 和钙在维持骨骼健康方面的重要性。维生素 D 对骨骼的有益作用可能对 HCV 感染患者至关重要，因为这些患者普遍存在低骨密度。许多药物会降低骨密度，而接触这些药物可能会增加 HCV 阳性患者的骨病。肝移植后会发生骨质流失，并且 HIV/HCV 合并感染且正在接受联合抗逆转录病毒治疗的患者骨密度通常较低。一些证据表明，利巴韦林会降低骨密度，这凸显了监测 HCV 治疗患者维生素 D 水平并在适当情况下开具补充剂的特殊需求。除了在钙代谢中的作用外，维生素 D 还是一种免疫调节剂，可减少炎症同时增强保护性免疫反应。HCV 患者的维生素 D 水平越高，肝纤维化和炎症就越少。最近的研究表明，低维生素 D 水平与接受聚乙二醇干扰素和利巴韦林治疗的 HCV 感染患者的治疗失败有关。如果这些发现得到证实，将为确保足够的维生素 D 水平提供另一个理由。文中提供了有关如何监测 HCV 感染患者的维生素 D 状态以及如何最有效地使用维生素 D 补充剂的信息。
