Association between hearing aid use and all-cause and cause-specific dementia: an analysis of the UK Biobank cohort

Background Dementia and hearing loss are both highly prevalent conditions among older adults. We aimed to examine the association between hearing aid use and risk of all-cause and cause-specific dementia among middle-aged and older-aged adults, and to explore the roles of mediators and moderators in their association.Methods We used data from the UK Biobank, a population-based cohort study, which recruited adults aged 40-69 years between 2006 and 2010 across 22 centres in England, Scotland, and Wales. We used Cox proportional hazards models to estimate hazard ratios (HRs) and 95% CIs between self-reported hearing aid use status (hearing loss with or without hearing aids) at baseline and risk of dementia (all-cause dementia, Alzheimer's disease, vascular dementia, and non-Alzheimer's disease non-vascular dementia). Dementia diagnoses were ascertained using hospital records and death-register data. We also analysed the roles of mediators (self-reported social isolation, loneliness, and mood) and moderators (self-reported education and income, smoking, morbidity, and measured APOE allele status).Findings After the exclusion of people who did not answer the question on hearing difficulties (n=25 081 [5 center dot 0%]) and those with dementia at baseline visit (n=283 [0 center dot 1%]), we included 437 704 people in the analyses. Compared with participants without hearing loss, people with hearing loss without hearing aids had an increased risk of all-cause dementia (HR 1 center dot 42 [95% CI 1 center dot 29-1 center dot 56]); we found no increased risk in people with hearing loss with hearing aids (1 center dot 04 [0 center dot 98-1 center dot 10]). The positive association of hearing aid use was observed in all-cause dementia and cause-specific dementia subtypes (Alzheimer's disease, vascular dementia, and non-Alzheimer's disease non-vascular dementia). The attributable risk proportion of dementia for hearing loss was estimated to be 29 center dot 6%. Of the total association between hearing aid use and all-cause dementia, 1 center dot 5% was mediated by reducing social isolation, 2 center dot 3% by reducing loneliness, and 7 center dot 1% by reducing depressed mood.Interpretation In people with hearing loss, hearing aid use is associated with a risk of dementia of a similar level to that of people without hearing loss. With the postulation that up to 8% of dementia cases could be prevented with proper hearing loss management, our findings highlight the urgent need to take measures to address hearing loss to improve cognitive decline.Funding National Natural Science Foundation of China and Shandong Province, Taishan Scholars Project, China Medical Board, and China Postdoctoral Science Foundation.Copyright (c) 2023 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license

Automated summary

The use of hearing aids is associated with a similar risk of dementia in people with hearing loss as compared to those without. Hearing loss accounts for 29.6% of the attributable risk of dementia, and the association between hearing aid use and dementia is partially mediated by reducing social isolation, loneliness, and depressed mood.