Distúrbios do sono e demência: uma revisão sistemática

Abstract

Introduction: It has been suggested that sleep disorders may increase the risk of developing dementia, a condition with important implications at individual, affective circle and health systems levels. Objective: To investigate whether there is a relationship between sleep disorders and the development of dementia. Methodology: A systematic review was carried out with MEDLINE, Literatura Latino Americana e do Caribe em Ciências da Saúde (LILACS) and SciELO databases from March to May, 2022, having as inclusion criteria longitudinal observational studies, published until May 2022, in English, that evaluated the relationship between the occurrence of sleep disorders and the onset of dementia and that had the work available for free. Studies in which only abstracts were available were excluded. The initial search was performed by 2 researchers and a discrepancy between the articles was found and checked by a third one. Results: The final 19 studies for analysis were divided into 4 groups: associating sleep disorders and dementia without a control group, with a control group, association of sleep duration with cases of dementia, and finally, studies that did not fit into the other categories. Conclusion: Sleep disorders and disturbances have been linked to an increased risk of developing dementia in adults; sleep duration, whether short and/or long, were associated with the onset of dementia; lower percentage and higher latency of REM sleep, lower efficiency and higher latency of total sleep, decreased amplitude and robustness of circadian activity rhythm, and delayed rhythms were also associated with higher risk. The mechanism of the sleep/cognitive decline relationship is not fully elucidated, with a failure of the glymphatic system in the clearance of accumulated brain metabolites as a candidate, but future studies are still needed to further clarify the basis of this and other proposals.