Vitamina A e sintomas da Esclerose Múltipla: revisão sistemática de estudos epidemiológicos e ensaios clínicos

Abstract

Introduction: Multiple sclerosis (MS) is the most prevalent autoimmune disorder today and is associated with demyelination of neurons in the central nervous system through activation of the immune system. Studies using vitamin A have been promising to improve the disease. Thus, the present dissertation aims to provide the best available evidence on the clinical impact of vitamin A on the symptoms-related outcomes of patients with MS. Methods: The article collection format was used for the production of two articles. The first one was a systematic review protocol article, used as a subsidy for the production of the second article, the systematic review. We searched on Pubmed, Embase, Scopus, Cinahl, Scielo, Web of Science, Cochrane Library, and Science Direct for studies evaluating the relationship of vitamin A supplementation and/or serum concentrations and symptoms in MS patients. For the design of the systematic review the PRISMA protocol was used. To assess the methodological quality of the studies, the JADAD scale was used for randomized controlled trials and Newcastle-Ottawa for observational studies. To extract all the data found, a database was created in the Microsoft Excel program. Results: At the initial search we found 2053 studies, and at the end of the searches 6 articles were selected for the research (2 randomized clinical trials and 4 cohorts). Of the six studies included, two used vitamin A supplementation and found that vitamin A is capable of containing upper limb disease progression and cognitive impairment, as well as significantly improving depression, total fatigue, and all three subscales fatigue (physical, cognitive and psychosocial). The other four studies measured serum vitamin A concentrations and found it was not associated with risk or number of relapses or worsening of the Kurtzke Expanded Disability Expanded Disability Status Scale. However, elevated serum retinol concentrations were associated with lower disease activity and were able to predict results of new lesions by magnetic resonance imaging. Conclusion: evidence identified in this study allow to recommend supplementation of vitamin A as an additional alternative to the treatment of MS. However, new controlled clinical trials well done are needed to define safe dosing better.