Moukayed Meis, Grant William B
School of Arts and Sciences, American University in Dubai, P.O. Box 28282, Dubai, United Arab Emirates.
Sunlight, Nutrition, and Health Research Center, P.O. Box 641603, San Francisco, CA, 94164-1603, USA.
Rev Endocr Metab Disord. 2017 Jun;18(2):167-182. doi: 10.1007/s11154-017-9415-2.
Global cancer incidence and mortality rates are high and increasing. Thus, it is imperative to find novel solutions to preventing cancer incidence and treating it at an affordable yet efficacious manner. The solar UVB-vitamin D-cancer hypothesis was first proposed in 1980 based on a geographical ecological study. Since then, numerous ecological and observational studies as well as studies of mechanisms have provided support for the hypothesis. However, observational studies have not provided consistent support, in part due to using a single blood draw from any season to use for serum 25-hydroxyvitamin D [25(OH)D] concentration in prospective studies with long follow-up times. Case-controls studies, in which blood is drawn near time of diagnosis, and prospective studies in which blood is drawn in the sunnier half of the year, are more likely to find significant inverse relations between 25(OH)D and cancer incidence. Three vitamin D plus calcium clinical trials have found significant reduction in all-cancer incidence. This paper reviews the evidence for vitamin D in reducing incidence of and increasing survival from breast, colorectal, lung, ovarian, pancreatic, and prostate cancer. The epidemiological evidence provides strong support for all of these types of cancer except for non-aggressive prostate cancer. Studies of the cellular mechanisms of vitamin D action in different cancer cell types, strongly indicate that vitamin D can exert protective and anti-tumorigenic activities that would retard cellular transformation, hyperplasia and cancer progression. Based on the scientific evidence reviewed in this paper, individuals and health providers can consider increasing 25(OH)D concentrations through sensible sun exposure and/or vitamin D supplementation to reduce risk of and, in conjunction with standard care, treat cancer. Public health acceptance of vitamin D for cancer prevention and treatment requires stronger support from vitamin D clinical trials.
全球癌症发病率和死亡率居高不下且呈上升趋势。因此，必须找到新颖的解决方案，以经济有效的方式预防癌症发生并进行治疗。基于一项地理生态学研究，太阳紫外线B-维生素D-癌症假说于1980年首次提出。从那时起，众多生态学和观察性研究以及机制研究都为该假说提供了支持。然而，观察性研究并未提供一致的支持，部分原因是在随访时间较长的前瞻性研究中，使用从任何季节抽取的单一血样来测定血清25-羟基维生素D [25(OH)D] 浓度。病例对照研究（在诊断时附近采血）以及在一年中阳光更充足的半年内采血的前瞻性研究，更有可能发现25(OH)D与癌症发病率之间存在显著的负相关关系。三项维生素D加钙的临床试验发现全癌发病率显著降低。本文综述了维生素D在降低乳腺癌、结直肠癌、肺癌、卵巢癌、胰腺癌和前列腺癌发病率以及提高生存率方面的证据。除了非侵袭性前列腺癌外，流行病学证据为所有这些类型的癌症提供了有力支持。对不同癌细胞类型中维生素D作用的细胞机制研究强烈表明，维生素D可以发挥保护和抗肿瘤活性，从而延缓细胞转化、增生和癌症进展。基于本文综述的科学证据，个人和医疗服务提供者可以考虑通过合理晒太阳和/或补充维生素D来提高25(OH)D浓度，以降低患癌风险，并结合标准治疗方法来治疗癌症。公众健康领域对维生素D用于癌症预防和治疗的接受程度需要来自维生素D临床试验的更强有力支持。
