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← Back to blogHearing Loss Is One of the Largest Modifiable Risk Factors for Dementia
Approximately 45% of dementia cases are attributable to 14 modifiable risk factors. Hearing loss alone accounts for 7%.
This figure comes from the 2024 Lancet Commission report. In the same report, untreated vision loss was also added to the list for the first time.
The contribution of hearing loss is often underestimated because it is usually assessed through self-report. When measured using audiometry, the proportion of dementia attributable to moderate and severe hearing loss in the US is 16.9%. This is approximately 8 times the estimates based on self-report.
Three pathways have been proposed to explain the mechanism. Deciphering speech from a degraded signal requires constant effort and depletes cognitive resources. People with hearing loss have smaller temporal cortex and hippocampal volumes. The third pathway involves social withdrawal and loneliness.
The treatment evidence is mixed. In the ACHIEVE randomized trial of 977 participants, there was no difference in cognitive decline over three years across the full sample. However, in the subgroup with a high cardiovascular risk burden, decline was 48% slower in the intervention arm. In a secondary analysis, this difference reached 61.6% in the highest-risk quartile.
For vision, the data are observational. Dementia risk was lower among those who underwent cataract surgery (HR 0.71). No such association was found for glaucoma surgery, which does not restore vision. However, there are no randomized trials, and the level of evidence is low.
For depression, the association is consistent, but the effect size is small: OR 1.47 for hearing loss, OR 1.75 for vision loss, and OR 2.19 when both are present.
Five practical steps:
1. Do not just ask about hearing; have it tested.
2. When a problem is identified in one sense, assess the other as well.
3. If cataracts are present, do not delay treatment.
4. Use hearing aids regularly. A protective association is seen only in those whose hearing actually improves.
5. Prioritize people at high risk.