The effect of caffeine and coffee on fatigue, disease severity, and cognitive outcomes in patients with multiple sclerosis: a systematic review

Abstract

Multiple sclerosis (MS) is a demyelinating condition of the central nervous system (CNS) with an immune-mediated nature. Caffeine is the most widely consumed psychoactive substance; however, no systematic review studies have comprehensively reviewed the evidence concerning its consequences in MS patients. Methods: This study was conducted following the Joanna Briggs Institute (JBI) Manual for Evidence Synthesis and PRISMA 2020 statement. Clinical evidence regarding the effects of caffeine or coffee consumption in MS patients was considered. A systematic search was performed in PubMed, Scopus, Web of Science, and Embase in October 2023, and updated via hand-searching in March 2024. JBI's critical appraisal tools were utilized to scrutinize the risk of bias. Results: Out of 297 screened records, eight studies were eventually found to meet our inclusion criteria. The sample size of the studies varied between 12 and 1372, and the study designs included retrospective cohort, RCT, single-blind crossover trial, single-arm pilot study (each one study), and cross-sectional (four studies). The disease phenotypes were a mixture of progressive and relapsing-remitting forms in all studies, except one. No significant association was found between the level of disability and coffee/caffeine intake; however, caffeine was reported to act as a cognitive enhancer in MS patients.