Association between hearing loss and cognitive decline in the elderly: A systematic review with meta-analysis study

Objective: Hearing loss has been pointed out as a potential predictor for cognitive decline. This study conducted a systematic review to evaluate the scientific evidence on the association between hearing loss in the elderly and cognitive decline, as well as whether race/color influences this relationship. Method: The search for studies was performed in the following electronic databases: MedLine/PubMed Web of Science, Scopus and Virtual Health Library, and MedRkiv up to August 2022. Studies with epidemiological designs that assess the association between hearing loss and cognitive decline in the elderly were eligible for inclusion. Three independent reviewers performed the selection, data extraction and evaluation of the quality of the studies using the Newcastle-Ottawa Scale. A meta-analysis using a random effects model estimated the global association measurements (Beta coefficient: β) and their 95% confidence intervals (95%CI), and the Higgins and Thompson indicator (I2) was also estimated to assess statistical heterogeneity among the studies. Results: 5,207 records were identified in the database surveys, of which only 18 were eligible studies, totaling 19,551 individuals. Hearing loss was associated with cognitive decline in the elderly, with statistical significance: β = -0.13; 95%CI = -0.23 to -0.04; I2 = 98.70%). For black individuals, the magnitude of the association increased: β = -0.64; 95%CI = -3.36 to 2.07; I2 = 95.65%, but it was not statistically significant. Conclusion: The findings of this systematic review showed the existence of a significant relationship between hearing loss and cognitive decline in the elderly, as well as signaling that among black individuals the magnitude of the association can be increased.