A major new study led by researchers from Columbia, Vanderbilt, Johns Hopkins, and other institutions has found that nearly one in three new dementia cases in older adults may be linked to hearing loss.
The study, published in JAMA Otolaryngology—Head & Neck Surgery, suggests that hearing loss could be one of the most significant modifiable risk factors for dementia in aging populations.
As the number of people living with dementia is expected to triple worldwide in the coming decades, scientists are increasingly focused on ways to reduce the risk.
While there is no cure for dementia, identifying and addressing preventable risk factors could help delay or reduce its impact. Hearing loss, which affects over two-thirds of older adults in the United States, is now emerging as one of those key risk factors.
Previous estimates suggested hearing loss contributed to anywhere from 2% to 19% of dementia cases.
This wide range was likely due to differences in how hearing loss was measured—many studies relied on self-reports, which often miss milder but clinically important cases. This new study used both objective hearing tests and self-reported data to provide a more accurate picture.
The researchers analyzed data from nearly 3,000 older adults between the ages of 66 and 90 who were part of a long-term health study across four U.S. states. None of the participants had dementia at the beginning of the study.
Between 2011 and 2019, participants underwent detailed cognitive testing and had their hearing evaluated once using pure tone audiometry, which is considered the gold standard in hearing assessments.
According to the results, 66% of participants had measurable hearing loss. Among those individuals, 9.9% developed dementia over the following years. In comparison, only 4.7% of people with normal hearing developed dementia.
Using statistical models to analyze these differences, the researchers concluded that hearing loss was linked to approximately 32% of dementia cases—meaning nearly a third might be preventable if hearing loss could be addressed effectively.
Mild hearing loss (defined as 26–40 decibels) accounted for an estimated 16% of dementia cases, while moderate or worse hearing loss contributed another 16%.
The impact was most noticeable among people aged 75 and older, where hearing loss was associated with up to 31% of dementia cases. However, the confidence range was wide—from a possible link to more than half of cases to no meaningful link at all—highlighting uncertainty in the estimates.
Similar patterns were seen when the data were split by gender and race, although again the statistical confidence varied, and no clear difference was found between men and women or among different racial groups. One clear takeaway was that self-reported hearing loss was not a reliable predictor of dementia risk. In fact, people who said they had hearing issues were less likely to develop dementia according to the data—suggesting that subjective reporting may miss more serious hearing problems.
This study did not track changes in hearing over time. It only looked at hearing loss measured at one moment, before any dementia symptoms appeared. So, while the results show a strong association, they do not prove that hearing loss directly causes dementia.
Still, the findings build on a growing body of research suggesting that hearing loss may contribute to brain changes or cognitive decline.
The researchers emphasized that objective hearing tests should be prioritized in future studies and clinical assessments. Better and earlier detection of hearing problems could help identify people at risk of dementia and open the door to preventive care.
In summary, this study highlights hearing loss as a major potential contributor to dementia in older adults. If confirmed by further research, treating hearing loss more aggressively—possibly with hearing aids or other interventions—could help reduce the global burden of dementia in the coming decades.
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The research findings can be found in JAMA Otolaryngology–Head & Neck Surgery.
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