Division of Cancer Prevention and Genetics, European Institute of Oncology, Milan, Italy.
Pigment Cell Melanoma Res. 2013 Jan;26(1):16-28. doi: 10.1111/pcmr.12036. Epub 2012 Nov 12.
Vitamin D is a steroid molecule, mainly produced in the skin that regulates the expression of a large number of genes. Several meta-analyses of epidemiological studies support the evidence that low vitamin D serum level, which is highly prevalent worldwide, could be a 'new' risk factor for many chronic diseases including cancer, and for all-cause mortality. A meta-analysis in healthy subjects suggested that current doses of vitamin D supplements could be associated with decrease in total mortality rates. However, these associations are insufficient to establish causality between vitamin D and all-cause mortality. Furthermore, long-term health effects of high doses of vitamin D, that is, prolonged supplementation and association with different baseline vitamin D levels, remain to be investigated. Several trials are ongoing but population-based, placebo-controlled randomized trials with total mortality as the main endpoint should be planned to confirm a real beneficial effect of vitamin D for non-skeletal diseases and to prove causality.
维生素 D 是一种类固醇分子，主要在皮肤中产生，可调节大量基因的表达。几项对流行病学研究的荟萃分析支持了以下证据，即全球范围内普遍存在的低血清维生素 D 水平可能是许多慢性疾病（包括癌症）和全因死亡率的“新”危险因素。一项对健康受试者的荟萃分析表明，目前维生素 D 补充剂的剂量可能与总死亡率的下降有关。然而，这些关联不足以确定维生素 D 与全因死亡率之间的因果关系。此外，高剂量维生素 D 的长期健康影响（即长期补充以及与不同的基线维生素 D 水平相关）仍有待研究。目前有多项试验正在进行中，但仍需要设计以总死亡率为主要终点的基于人群的、安慰剂对照的随机试验，以证实维生素 D 对非骨骼疾病的真正有益作用并证明其因果关系。
