Randomised trials reported up to Dec 31, 2012, did not confirm that vitamin D supplementation could protect from non-skeletal health conditions affecting adults, as was expected on the basis of data from observational studies. To examine whether the more recently published meta-analyses and trials would change past conclusions, we systematically reviewed meta-analyses of vitamin D supplementation and non-skeletal disorders published between Jan 1, 2013, and May 31, 2017, that included study participants of all ages, including pregnant women. We also searched for randomised trials not included in meta-analyses. We identified 87 meta-analyses, of which 52 were excluded because they contained less recent literature or were of suboptimal quality. We retrieved 202 articles on trials that were not included in meta-analyses. Recent meta-analyses reinforce the finding that 10-20 μg per day of vitamin D can reduce all-cause mortality and cancer mortality in middle-aged and older people. Although vitamin D doses were greater than those assessed in the past, we found no new evidence that supplementation could have an effect on most non-skeletal conditions, including cardiovascular disease, adiposity, glucose metabolism, mood disorders, muscular function, tuberculosis, and colorectal adenomas, or on maternal and perinatal conditions. New data on cancer outcomes were scarce. The compilation of results from 83 trials showed that vitamin D supplementation had no significant effect on biomarkers of systemic inflammation. The main new finding highlighted by this systematic review is that vitamin D supplementation might help to prevent common upper respiratory tract infections and asthma exacerbations. There remains little evidence to suggest that vitamin D supplementation has an effect on most conditions, including chronic inflammation, despite use of increased doses of vitamin D, strengthening the hypothesis that low vitamin D status is a consequence of ill health, rather than its cause. We further hypothesise that vitamin D supplementation could exert immunomodulatory effects that strengthen resistance to acute infections, which would reduce the risk of death in debilitated individuals. We identified many meta-analyses of suboptimal quality, which is of concern. Future systematic reviews on vitamin D should be based on data sharing so that data for participants with the same outcomes measured in the same way can be pooled to generate stronger evidence.

中文翻译：

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补充维生素D对非骨骼疾病的影响：荟萃分析和随机试验的系统评价。

根据观察研究的数据，截至2012年12月31日的随机试验未证实补充维生素D可以预防影响成年人的非骨骼健康状况。为了检查最近发表的荟萃分析和试验是否会改变过去的结论，我们系统地回顾了2013年1月1日至2017年5月31日期间发表的补充维生素D和非骨骼疾病的荟萃分析，其中包括所有年龄段，包括孕妇。我们还搜索了荟萃分析中未包括的随机试验。我们确定了87项荟萃分析，其中52项被排除在外，因为它们包含的文献较少或质量欠佳。我们检索了202篇关于未纳入荟萃分析的试验的文章。最近的荟萃分析进一步证实了这一发现，即每天10-20μg维生素D可以降低中老年人的全因死亡率和癌症死亡率。尽管维生素D的剂量大于过去评估的剂量，但我们没有发现新的证据表明补充剂可对大多数非骨骼疾病产生影响，包括心血管疾病，肥胖，葡萄糖代谢，情绪异常，肌肉功能，结核病和结直肠癌腺瘤或产妇和围产期疾病。关于癌症结局的新数据很少。来自83个试验的结果汇总显示，补充维生素D对全身性炎症的生物标志物无显着影响。该系统评价强调的主要新发现是补充维生素D可能有助于预防常见的上呼吸道感染和哮喘加重。几乎没有证据表明，尽管增加了维生素D的使用剂量，但补充维生素D仍对大多数状况（包括慢性炎症）有影响，从而强化了以下假设：低维生素D状态是不良健康的结果，而不是其病因。我们进一步假设，补充维生素D可以发挥免疫调节作用，从而增强对急性感染的抵抗力，从而降低衰弱者的死亡风险。我们确定了许多次优质量的荟萃分析，这值得关注。