Hearing Loss Linked to Nearly One-third of Dementia Cases in Older Adults- What it Means

A recent article, "Hearing loss linked to nearly one-third of dementia cases in older adults" from McKnights, references a study published on April 17, 2025, in JAMA Otolaryngology-Head & Neck Surgery. Let’s break down the study’s claims, assess its implications, and explore actionable steps for seniors and their families.

Analysis of the Study

The study, conducted on 2,946 older adults with a mean age of 75, found that nearly one-third (32%) of dementia cases at a "population level" could be attributed to hearing loss, as measured through audiometric testing. This figure is derived from the population attributable fraction (PAF), a statistical measure estimating the proportion of a disease (dementia, in this case) that might be prevented if a specific risk factor (hearing loss) were eliminated. 

Notably, the study found no significant association between self-reported hearing loss and dementia risk—only audiometrically confirmed hearing loss showed this link. The association was stronger in women, those over 75, and white individuals.

Does Hearing Loss "Cause" Dementia, or Contribute to Faster Onset?

The study does not claim that hearing loss directly causes dementia. Instead, it highlights a correlation, suggesting that hearing loss may contribute to dementia risk at a population level. The article and related sources  emphasize that if the relationship is causal, addressing hearing loss could potentially delay or prevent up to 32% of dementia cases. However, causality is not proven here. Several mechanisms are proposed to explain the link:

• Cognitive Load Hypothesis: Hearing loss forces the brain to expend more energy on processing sounds, leaving fewer resources for memory and cognitive functions, potentially accelerating cognitive decline.

• Social Isolation: Hearing loss can lead to social withdrawal, which is a known risk factor for dementia due to reduced cognitive stimulation.

• Brain Atrophy: Some research suggests hearing loss may cause faster brain shrinkage in areas related to memory and cognition.

The study’s language—“could be attributed to”—indicates an association, not causation. It aligns with prior research, such as the 2020 Lancet Commission on Dementia, which identified hearing loss as one of 12 modifiable risk factors, estimating it contributes to about 8% of global dementia cases.  Similarly, isolation has been associated with a 28% higher risk of developing dementia over nine years, regardless of race or ethnicity, according to a study in the Journal of the American Geriatrics Society This new study’s higher estimate (32%) reflects a focus on older adults with clinically significant hearing loss, but it doesn’t confirm that hearing loss directly triggers dementia. Instead, it suggests hearing loss might accelerate the onset or progression of dementia symptoms in those already at risk.

Limitations and Critical Examination

• Correlation vs. Causation: The study relies on observational data, which cannot establish causality. Other factors, like shared underlying causes (e.g., vascular issues affecting both hearing and cognition), might explain the link.

• Self-Reported vs. Audiometric Data: The lack of association with self-reported hearing loss raises questions. It could mean many older adults are unaware of their hearing loss, or that self-reports are unreliable, potentially skewing the perceived impact.

• Demographic Bias: The stronger link in women, white individuals, and those over 75 might reflect demographic differences in the study population rather than universal truths. For example, women tend to live longer, increasing their dementia risk overall.

• Interventional Evidence: While the study suggests treating hearing loss might delay dementia, it doesn’t provide direct evidence. Related research, like the 2023 ACHIEVE study, found that hearing aids slowed cognitive decline by 48% in high-risk older adults over three years, but this also isn’t definitive proof of dementia prevention.

• Meaning of "Population Level" Relationship: When a study finds a correlation "at a population level," it means the relationship between two variables (e.g., hearing loss and dementia) is observed across a large group of people, typically representing a broad population. This correlation reflects a general trend or pattern in the data when averaged over the entire group, but it doesn’t necessarily apply to every individual within that population. For example, a study might find that higher coffee consumption is correlated with increased anxiety at a population level, meaning this trend holds true when looking at the group as a whole.

• Meaning of "Individual Level" Relationship: The alternative is finding a correlation "at an individual level," where the relationship between variables is examined for specific individuals rather than the group. This approach looks at how changes in one variable correspond to changes in another for each person. For instance, a study might track an individual’s coffee intake and anxiety levels over time to see if they rise and fall together for that person.

Comparison:

• Population-level correlations are generally more reliable for understanding broad trends because they are based on larger sample sizes, which reduce the impact of outliers and individual variability. They’re useful for making generalizations about a group, but they can mask individual differences. For example, a population-level correlation might show that smoking increases lung cancer risk, but some individuals who smoke might never develop cancer due to other factors like genetics.
• Individual-level correlations can be less reliable for generalizing because they’re based on fewer data points (just one person or a small group) and are more susceptible to noise, such as random fluctuations in the data or unaccounted variables. However, they’re more precise for understanding a specific person’s experience, which can be critical in personalized medicine or tailored interventions.
• Merits of Both:  In short, population-level correlations are more reliable for broad insights but less precise for individuals, while individual-level correlations are more specific but less generalizable. The choice depends on the study’s goal—general trends versus personalized understanding.

What the Study Actually Tells Us

The study tells us that hearing loss, when confirmed through objective testing, is strongly associated with dementia risk in older adults, particularly those over 75. It estimates that addressing hearing loss could theoretically reduce population-level dementia risk by 32%, but this is a hypothetical projection, not a guaranteed outcome. The findings underscore hearing loss as a significant, modifiable risk factor, but they don’t confirm it as a direct cause of dementia. Instead, hearing loss likely interacts with other risk factors, potentially hastening the appearance of dementia symptoms in vulnerable individuals.  In making individual health decisions, it is just one of several variable that may factor in health care decisions.

Actionable Steps for Seniors

Based on the study’s findings, seniors can take proactive steps to potentially reduce their dementia risk:

• Get Regular Hearing Tests: Since the study found a link only with audiometrically confirmed hearing loss, seniors should prioritize objective hearing assessments, especially if they’re over 60, as one-third of this age group experiences hearing loss. Regular testing can catch issues early.

• Use Hearing Aids if Needed: If hearing loss is detected, using hearing aids may help. The ACHIEVE study suggests hearing aids can slow cognitive decline in high-risk individuals. Even if they don’t prevent dementia, they can improve quality of life by enhancing communication and reducing social isolation.

• Stay Socially Engaged: Hearing loss can lead to isolation, a known dementia risk factor. Seniors should maintain social connections, whether through community activities, day centers, or family interactions, to keep their brains active.

• Monitor Overall Health: Hearing loss is one of many modifiable risk factors for dementia. Seniors should also address other risks, like high cholesterol, physical inactivity, and depression, as outlined in the 2024 Lancet Commission Report, which identifies 14 such factors (action items for all 14 risk factors are outlined at the end of this article).

• Advocate for Accessibility: Hearing aids can be expensive, and access varies. Seniors should explore subsidies or programs that make hearing aids more affordable, as equitable access is crucial for widespread impact.

How Family Members Can Help

Family members can play a critical role in supporting seniors to act on this information:

• Encourage Hearing Tests: Family members can gently encourage seniors to get their hearing checked, especially if they notice signs like difficulty following conversations or frequent misunderstandings. Offering to accompany them to appointments can make the process less daunting.

• Support Hearing Aid Adoption: If hearing aids are recommended, families can help seniors adjust to them. This might involve researching affordable options, assisting with fittings, or providing emotional support, as some seniors may resist using hearing aids due to stigma or discomfort.

• Facilitate Social Interaction: Families can help combat isolation by organizing regular visits, outings, or activities that keep seniors engaged. For example, involving them in family events or community programs can provide cognitive stimulation.

• Monitor for Cognitive Changes: Since hearing loss may accelerate dementia symptoms, families should watch for early signs of cognitive decline, like memory lapses or difficulty with tasks. If noticed, they can encourage cognitive screening, as suggested by related research on falls and dementia risk.

• Advocate for Holistic Care: Families can ensure seniors see healthcare providers who take a comprehensive approach, addressing hearing loss alongside other dementia risk factors like diet, exercise, and mental health.

Conclusion

While the study highlights an important link, it’s worth questioning the narrative that hearing loss is a primary driver of dementia. The 32% PAF figure is striking, but it’s a population-level estimate, not a personal risk prediction. Other factors, like genetics or socioeconomic barriers to healthcare, might play larger roles for some individuals. Additionally, the focus on hearing loss shouldn’t overshadow other modifiable risks—like vision loss, isolation, or smoking—which also appear to contribute to dementia rates. Seniors and families should view hearing loss as one piece of a larger puzzle, addressing it within a broader strategy for brain health.

In summary, the study suggests hearing loss is a significant risk factor that may hasten dementia onset, but it doesn’t prove causation. Seniors should prioritize hearing tests and interventions like hearing aids, while families can support them through encouragement, social engagement, and advocacy for comprehensive care. This approach can potentially delay cognitive decline, though it’s not a guaranteed shield against dementia.

The 14 Risk Factors identified by Lancet

1. Ensure good quality education is available for all and encourage cognitively stimulating activities in midlife to protect cognition.
2. Make hearing aids accessible for people with hearing loss and decrease harmful noise exposure to reduce hearing loss.
3. Treat depression effectively.
4. Encourage use of helmets and head protection in contact sports and on bicycles.
5. Encourage exercise because people who participate in sport and exercise are less likely to develop dementia.
6. Reduce cigarette smoking through education, price control, and preventing smoking in public places and make smoking cessation advice accessible.
7. Prevent or reduce hypertension and maintain systolic blood pressure of 130 mm Hg or less from age 40 years.
8. Detect and treat high LDL cholesterol from midlife.
9. Maintain a healthy weight and treat obesity as early as possible, which also helps to prevent diabetes.
10. Reduce high alcohol consumption through price control and increased awareness of levels and risks of overconsumption.
11. Prioritize age-friendly and supportive community environments and housing and reduce social isolation by facilitating participation in activities and living with others.
12. Make screening and treatment for vision loss accessible for all.
13. Reduce exposure to air pollution.
14. Considerations for People with  Dementia:

• Interventions after diagnosis help people to live well with dementia, including planning for the future. Multicomponent coping interventions for family carers and managing neuropsychiatric symptoms are important and should be person-centred.
• Neuropsychiatric symptoms should be treated, and clear evidence exists that care-coordinated multicomponent interventions are helpful. Activity interventions also reduce neuropsychiatric symptoms and are important to maintain enjoyment and purpose for people with dementia. There is no evidence for exercise as an intervention for neuropsychiatric symptoms.
• Cholinesterase inhibitors and memantine should be provided for people with Alzheimer's disease and Lewy body dementia. These drugs are cheap, with relatively few side-effects; attenuate cognitive deterioration to a modest extent, with good evidence of a long-term effect; and are available in most high-income countries, although less so in low-income and middle-income countries.
• There is progress in and hope for disease-modifying treatments for Alzheimer's disease, with some trials of amyloid-β-targeting antibodies showing modest efficacy in reducing deterioration after 18 months of treatment. However, effects are small and drugs have been trialled in people with mild disease and people with few other illnesses. These treatments have been licensed in some countries but have notable side-effects, with few data about long-term effects. The expense of these treatments and the precautions that must be taken, which have resource implications for staff, scanning, and specialist blood testing, could limit their use and be challenging for health systems. We recommend that full information is shared broadly about the unknown long-term effects, the absence of data about the effects in people with multimorbidity, and the scale of efficacy and side-effects, particularly for APOE ε4 genotype carriers. We recommend that people on amyloid-β-targeting antibodies are carefully monitored.
• Cerebrospinal fluid or blood biomarkers should be used clinically only in people with dementia or cognitive impairment to help to confirm or exclude a diagnosis of Alzheimer's disease. Biomarkers are only validated in largely White populations, limiting generalizability and raising health equity concerns.
• People with dementia who become acutely physically unwell and need to be admitted to hospital deteriorate faster cognitively than others with dementia. It is important to protect physical health and ensure that people have help if needed to ensure that they eat and drink enough and can take medication.
• COVID-19 exposed the vulnerability of people with dementia. We need to learn from this pandemic and also protect people with dementia as their lives and wellbeing, and that of their families, have been valued less than that of people without dementia.