Abstract：
The role of vitamin A in the pathophysiological context of coronavirus disease 2019 (COVID-19) represents a current challenge, given the major impact of COVID-19 on morbidity and mortality and the importance of retinol in pulmonary and immunomodulatory functions. The aim of this review is to assess the relationship between vitamin A nutritional status and clinical outcomes in people with COVID-19. The PubMed, Web of Science, Scopus and ScienceDirect databases were used to search for observational studies that assessed retinol levels in hospitalized individuals with COVID-19, following the PRISMA recommendations. A total of 1,912 articles were identified and seven met the inclusion criteria. Four studies showed borderline or deficient retinol blood levels (retinol <0.20 mg/L or <0.70 mol/L) in people with COVID-19, associated with worsened clinical outcomes. In the other three studies lower mean values of this vitamin were identified in COVID-19 symptomatic groups compared to asymptomatic or convalescent groups that showed worse clinical outcomes. The results suggest a possible association between retinol and COVID-19 outcomes. However, there is a clear need to develop clinical trials to elucidate the role of vitamin A in the pathophysiological process of COVID-19.
摘要：
维生素A在2019年冠状病毒病（COVID-19）的病理生理背景中的作用是当前的挑战，鉴于COVID-19对发病率和死亡率的主要影响以及视黄醇在肺和免疫调节功能中的重要性。本综述的目的是评估COVID-19患者维生素A营养状况与临床结局之间的关系。PubMed,WebofScience,根据PRISMA建议，使用Scopus和ScienceDirect数据库搜索评估COVID-19住院患者视黄醇水平的观察性研究。共确定了1,912篇文章，其中7篇符合纳入标准。四项研究显示，COVID-19患者的视黄醇血液水平接近或缺乏（视黄醇<0.20mg/L或<0.70mol/L），与临床结局恶化有关。在其他三项研究中，与无症状或康复组相比，COVID-19有症状组的这种维生素的平均值较低，后者的临床结果较差。结果表明，视黄醇与COVID-19结果之间可能存在关联。然而,显然有必要开展临床试验，以阐明维生素A在COVID-19病理生理过程中的作用。
