Potentially modifiable risk factors for dementia include hypertension, obesity, diabetes, and hearing loss.

Livingston G, Huntley J, Sommerlad A, et al. Dementia prevention, intervention, and care: 2020 report of the Lancet Commission. The Lancet. July 30, 2020. doi.org/10.1016/S0140-6736(20)30367-6.

Hearing loss is the largest modifiable risk factor for dementia, accounting for 8% of all dementia cases worldwide. 

 

What is the connection between hearing loss and dementia, and how can patients mitigate this risk? 

 

Quantifying the risk 

 

A growing body of evidence supports the idea that hearing loss is a risk factor for dementia. A meta-analysis of 36 studies published in 2020 found that people with hearing loss had a 1.9-fold increased risk of cognitive impairment and a 1.4-fold increased risk of dementia, compared with those without hearing loss. Another study published in 2021 analyzed data from over 100,000 individuals and found that hearing aid use was associated with a 13% reduction in the risk of dementia, suggesting that addressing hearing loss may have a preventive effect on dementia.

A 2023 study published in Journal of the American Medical Association found that the prevalence of dementia increased with increasing severity of hearing loss.

Huang AR, Jiang K, Lin FR, Deal JA, Reed NS. Hearing loss and dementia prevalence in older adults in the US. JAMA. 2023;329(2):171-173.

The study consisted of 2,413 older adults, with 53.3% of participants aged 80 years or older. The prevalence of dementia in participants with normal hearing was 6.19%, with 8.93% in those with mild hearing loss. For participants with moderate or severe hearing loss, the prevalence of dementia increased to 16.52%.

 

 

What is the underlying mechanism? 

 

While multiple studies have shown that hearing loss increases the risk of dementia, the underlying mechanisms are not well understood.

Hearing loss and the dementia connection. Johns Hopkins. November 12, 2021.

However, several mechanisms have been proposed to explain the link between hearing loss and dementia. One hypothesis is that hearing loss leads to social isolation and reduced cognitive stimulation, which in turn may increase the risk of dementia. Another possibility is that hearing loss contributes to cognitive load and reduces the brain's ability to process and store information, which may eventually lead to cognitive decline. 

 

In an article published by the Cleveland Clinic, Dr. Ronan Factora, MD, a geriatric medicine specialist, said, “The cause behind this link is unclear. But one theory is that hearing loss tends to cause some people to withdraw from conversations and participate less in activities. As a result, you become less social and less engaged.”

Can hearing loss lead to dementia? Cleveland Clinic. April 12, 2022.

 

 

How to reduce the risk of dementia? 

 

In the JAMA study, investigators found that for participants with moderate to severe hearing loss, the use of hearing aids was linked to a 32% decrease in the prevalence of dementia. 

"This study refines what we've observed about the link between hearing loss and dementia, and builds support for public health action to improve hearing care access," said lead author Alison Huang, PhD, MPH, in a press release published by Science Daily.

New study links hearing loss with dementia in older adults. ScienceDaily. January 10, 2023.

 

 

This work suggests that the use of hearing aids is protective against dementia. However, according to the National Institute on Deafness and Other Communication Disorders (NIDCD), only 30% of adults aged 70 years and older with hearing loss who could benefit from the use of hearing aids actually use them.

Quick statistics about hearing. NIDCD.

For adults aged 20 to 69, that number is 16%. 

 

One barrier to more widespread hearing aid use is the cost associated with purchasing a hearing aid, which often encompasses a medical exam, a prescription, or a fitting adjustment by an audiologist.

FDA finalizes historic rule enabling access to over-the-counter hearing aids for millions of americans. FDA. August 16, 2022.

To combat this, the US FDA established a new category of OTC hearing aids. These OTC hearing aids will allow individuals with mild to moderate hearing loss to buy hearing aids directly from stores, forgoing the need for medical exams or prescriptions. 

 

Other strategies for preventing cognitive decline associated with hearing loss include staying socially engaged, engaging in mentally stimulating activities, and maintaining a healthy lifestyle, including regular exercise and a healthy diet.

 

Prevention of hearing loss 

 

Regardless of the underlying mechanism, the evidence is clear that hearing loss is a significant risk factor for dementia. However, there is hope for prevention. One study published in the Lancet in 2017 found that treating hearing loss with hearing aids was associated with a reduction in cognitive decline. The study followed over 2,000 adults aged 50 and older for 18 years and found that those who used hearing aids had a 75% reduced risk of cognitive decline compared to those who did not use hearing aids.

While hearing aids are great tools for those suffering from hearing loss, an emphasis on hearing loss prevention strategies is key. Healthcare providers should discuss ways to prevent noise-related hearing loss with their patients because prevention of hearing loss is key to reducing the risk of dementia. 

This can be achieved through various measures, including avoiding exposure to loud noise, using ear protection when necessary, treating infections promptly, and managing underlying health conditions that may contribute to hearing loss, such as diabetes and cardiovascular disease. 

These devices can improve communication and reduce the cognitive load associated with hearing loss.

Some other prevention strategies include:

Jividen S. Is Hearing Loss an Early Sign of Dementia? Verywell Health. January 4, 2022.

 

• Using headphones or earplugs whenever in loud spaces

• Avoiding exposure to loud noise

• Treating infections promptly

• Managing underlying health conditions that may contribute to hearing loss, such as diabetes and cardiovascular disease

• Lowering the volume when watching television or listening to music 

• Getting regular hearing checks