Boucher Barbara J
Blizard Institute, Barts & The London school of Medicine & Dentistry, Queen Mary University of London, London, UK.
Endocr Connect. 2020 Oct;9(9):R195-R206. doi: 10.1530/EC-20-0274.
Our knowledge of vitamin D has come a long way since the 100 years it took for doctors to accept, between 1860 and 1890, that both sunlight and cod liver oil (a well-known folk remedy) cured and prevented rickets. Vitamins D2/D3 were discovered exactly a hundred years ago, and over the last 50 years vitamin D has been found to have many effects on virtually all human tissues and not just on bone health, while mechanisms affecting the actions of vitamin D at the cellular level are increasingly understood, but deficiency persists globally. Observational studies in humans have shown that better provision of vitamin D is strongly associated, dose-wise, with reductions in current and future health risks in line with the known actions of vitamin D. Randomised controlled trials, commonly accepted as providing a 'gold standard' for assessing the efficacy of new forms of treatment, have frequently failed to provide supportive evidence for the expected health benefits of supplementation. Such RCTs, however, have used designs evolved for testing drugs while vitamin D is a nutrient; the appreciation of this difference is critical to identifying health benefits from existing RCT data and for improving future RCT design. This report aims, therefore, to provide a brief overview of the evidence for a range of non-bony health benefits of vitamin D repletion; to discuss specific aspects of vitamin D biology that can confound RCT design and how to allow for them.
自1860年至1890年期间医生花了100年才接受阳光和鱼肝油（一种著名的民间疗法）都能治愈和预防佝偻病以来，我们对维生素D的认识有了长足的进步。维生素D2/D3恰好在一百年前被发现，在过去的50年里，人们发现维生素D几乎对所有人体组织都有多种作用，而不仅仅是对骨骼健康有作用，同时，人们对影响维生素D在细胞水平上作用的机制的理解也越来越深入，但全球维生素D缺乏的情况仍然存在。对人类的观察性研究表明，更好地补充维生素D在剂量上与降低当前和未来的健康风险密切相关，这与维生素D已知的作用相符。随机对照试验通常被认为是评估新治疗方法疗效的“金标准”，但经常未能为补充维生素D所预期的健康益处提供支持性证据。然而，此类随机对照试验采用的是为测试药物而设计的方案，而维生素D是一种营养素；认识到这种差异对于从现有随机对照试验数据中确定健康益处以及改进未来的随机对照试验设计至关重要。因此，本报告旨在简要概述补充维生素D对一系列非骨骼健康有益的证据；讨论维生素D生物学中可能混淆随机对照试验设计的具体方面以及如何应对这些方面。
