JOHANNESBURG, SOUTH AFRICA — Hearing loss may deserve greater attention earlier in life as part of efforts to reduce dementia risk, according to research from South Africa that adds to growing evidence connecting sensory health with cognitive aging.
The study, published in Alzheimer’s & Dementia, examined hearing and vision among 567 older adults living in rural South Africa. Researchers found that hearing impairment was associated with a higher likelihood of dementia and, importantly, with a greater probability of dementia two years later among people who did not have dementia when their hearing was initially assessed.
The findings are particularly notable because much of the research connecting hearing loss and dementia has come from higher-income countries. The researchers wanted to determine whether similar relationships could be seen in a rural African population, where sensory impairment is common and access to hearing and vision care may be limited.
Hearing Loss Associated With Higher Dementia Risk
The analysis drew on the Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa (HAALSI), a population-based study conducted in the Agincourt sub-district of Mpumalanga Province.
Hearing impairment was common. Approximately 47% of the 567 participants met the study’s definition of hearing impairment. Among participants with dementia, that figure climbed to about 70%, compared with 36% among those with normal cognition.
After accounting for age, education, household wealth, cardiovascular conditions, depression and several other factors that could influence cognitive health, hearing impairment was associated with approximately 2.5 times greater odds of dementia.
Vision impairment was also associated with dementia. The relationship was especially pronounced when sensory difficulties occurred together. Researchers calculated a predicted dementia probability of about 5% when neither hearing nor vision impairment was present. When hearing impairment, distance vision impairment and near vision impairment were all present, that probability increased to 34% — nearly seven times higher.
The study’s follow-up analysis offered another important finding. Among people who did not have dementia at the beginning of the study, hearing impairment remained associated with a higher probability of dementia two years later. The same association was not seen for vision impairment after people with existing dementia were excluded.
“These findings suggest that hearing impairment may serve as an early risk factor for cognitive decline.”
The researchers cautioned that the relatively short two-year follow-up cannot establish that hearing loss causes dementia. Other health, social or biological factors may contribute to both conditions, and changes associated with dementia itself could potentially affect sensory function.
Why Hearing and Cognitive Health May Be Connected
Researchers are still working to understand why hearing loss and cognitive decline are so consistently linked. There may not be a single explanation.
Possible pathways include shared underlying health conditions, greater mental effort required to understand speech when hearing is reduced, less auditory stimulation reaching the brain, and changes in social activity and engagement. Several of these factors may also interact over time.
What has become increasingly clear is that hearing health is relevant to the broader conversation about healthy aging. The 2024 Lancet Commission on dementia prevention identified hearing loss as one of 14 potentially modifiable risk factors for dementia and estimated that addressing these factors collectively could potentially prevent or delay a substantial proportion of dementia cases.
The South African findings add an important perspective because hearing and vision problems were common in the study population while use of corrective devices was low. The researchers argue that improving access to sensory care could therefore represent an important and potentially achievable public health opportunity.
“Our findings highlight the need for targeted interventions to improve vision and hearing function as part of dementia prevention strategies.”
That does not mean treating hearing loss has been proven to prevent dementia. Instead, the findings strengthen the case for identifying hearing difficulties earlier and studying whether intervention can influence cognitive health over time.
Recent Hearing Aid Research Adds to the Picture
That question has taken on greater importance as researchers move beyond simply documenting the association between hearing loss and dementia and begin testing what happens when hearing loss is treated.
Recent findings from the CHOICE randomized clinical trial, for example, examined hearing aid use in 703 adults age 60 and older who had both hearing loss and mild cognitive impairment (MCI).
After two years, hearing aids did not significantly reduce progression to dementia-level impairment, which was the study’s primary outcome. However, researchers observed an intriguing finding in the opposite direction: 15.3% of participants receiving hearing aids improved from a Clinical Dementia Rating (CDR) score of 0.5 to 0, compared with 2.4% of participants in the comparison group.
Put more simply, approximately one in six participants receiving hearing aids improved to a CDR score considered unimpaired, compared with roughly one in 42 in the comparison group.
Because cognitive improvement was a secondary outcome, the result does not prove that hearing aids improve cognition. But it adds to evidence suggesting that the relationship between hearing intervention and cognitive health may be more nuanced than whether hearing aids simply “prevent dementia.”
The landmark ACHIEVE randomized trial has pointed in a similar direction. Hearing intervention did not significantly slow cognitive decline across the trial’s entire population, but participants who entered the study at greater risk for cognitive decline appeared to receive substantially greater cognitive benefit from hearing intervention.
Moving Hearing Care Earlier in Healthy Aging
Taken together, these studies support a broader shift in how hearing loss is viewed as people age.
Hearing loss has traditionally been treated primarily when communication problems become significant enough to interfere with everyday life. Growing evidence connecting hearing, social engagement, brain health and cognition raises the question of whether hearing should be addressed earlier — before difficulties become severe.
The South African study does not establish that hearing loss causes dementia, and current clinical trials do not establish hearing aids as a way to prevent dementia in an individual patient. But hearing loss is common, measurable and treatable, making it one of the more actionable health issues associated with cognitive aging.
There are also established reasons to address hearing loss regardless of its eventual effect on dementia risk. Better access to communication can support relationships, social participation, independence and quality of life.
The unanswered question — and one likely to receive increasing attention — is whether identifying and treating hearing loss earlier can provide an additional benefit by helping preserve cognitive health over the longer term.
References:
1. Guo M, Bassil DT, Farrell MT, et al. Sensory impairment and dementia risk among older adults in rural South Africa. Alzheimer’s & Dementia. 2025;21:e70513. doi:10.1002/alz.70513.
2. Chen Y, Shi H, Xiang M, et al. Hearing Intervention for Older Adults With Mild Cognitive Impairment: The CHOICE Randomized Clinical Trial. JAMA Neurology. Published online September 28, 2026. doi:10.1001/jamaneurol.2026.3395.
3. Lin FR, Pike JR, Albert MS, et al. Hearing Intervention Versus Health Education Control to Reduce Cognitive Decline in Older Adults With Hearing Loss in the USA (ACHIEVE): A Multicentre, Randomised Controlled Trial. The Lancet. 2023;402(10404):786-797. doi:10.1016/S0140-6736(23)01406-X.
4. Livingston G, Huntley J, Liu KY, et al. Dementia prevention, intervention, and care: 2024 report of the Lancet Standing Commission. The Lancet. 2024;404:572-628. doi:10.1016/S0140-6736(24)01296-0.
