Selenium supplementation and clinical outcomes: an umbrella review protocol

BackgroundSelenium is a trace element essential for the normal functions of different human body systems and its deficiency has been associated with different disease states. In recent years, many systematic reviews of randomized clinical trials in humans have demonstrated various properties of selenium such as antioxidant, anti-inflammatory, increased immunity, blocking tumour invasion and metastasis in various pathological conditions. Therefore, there is need to summarize these recent findings in one single paper to facilitate the decision making of clinicians and policy makers regarding the inclusion of selenium supplementation in routine clinical practice, treatment guidelines and essential medicine list. This study would guide researchers towards future research and design of clinical trials. ObjectivesThe objective of this umbrella review is to assess the clinical outcomes of selenium supplementation in different disease states and to determine its therapeutic implications. Eligibility criteriaOnly systematic reviews of randomized clinical trials reporting clinical outcomes after the use of selenium alone as a supplement in the management of diseases will be included. While primary studies, systematic reviews that involved the administration of selenium in combination with other trace elements for the prevention or treatment of diseases will be excluded. MethodsThe following databases will be searched by three independent reviewers: MEDLINE, PUBMED, EMBASE, COCHRANE database of systematic reviews, CINAHL, JBI Evidence synthesis, EPISTEMONIKOS, SCOPUS, Web of Science and TRIP PRO. Unpublished reviews will be searched using ProQuest for dissertations and Theses, Canadian Agency for drugs and Technologies in Health (CADTH) database of Grey matters and GOOGLE scholar. Systematic reviews published in the last 10 years (2013 to 2023). There will be no language restriction. The services of a translator will be employed if studies in other languages were found. Selection of reviews and data extraction will be done by 3 independent reviewers. Summary of findings will be presented in tables accompanied by texts where necessary. Strengths and limitations of this studyThis is the first umbrella review on the use of selenium supplements for disease management. Secondly, the findings from this study would facilitate the decision making of clinicians and policy makers regarding the inclusion of selenium supplementation in routine clinical practice, treatment guidelines and essential medicine list. Nevertheless, a major limitation of this umbrella review would be a reduced scope of eligible studies because only systematic reviews/ or meta-analysis that included randomized clinical trials will be considered.