The biggest dementia risk you can change isn’t poor diet or lack of exercise — and nearly half of cases could be prevented or delayed

by Adrienne Erin

You do the crossword every morning. You’ve switched to blueberries and walnuts, and maybe you downloaded a brain-training app. Those habits aren’t bad. But according to the world’s leading expert panel on dementia prevention, the change that could matter most is one many people put off for years: getting their hearing checked.

Key Takeaways

  • The 2024 Lancet Commission on dementia found that hearing loss is tied with high LDL (“bad”) cholesterol as the single biggest modifiable risk factor for dementia, each linked to about 7% of cases.
  • The same report estimates that addressing 14 modifiable risk factors across life could prevent or delay nearly half of all dementia cases.
  • Hearing loss is extremely common with age. About 55% of Americans 75 and older have disabling hearing loss, yet fewer than 1 in 3 adults 70 and older who could benefit from hearing aids have ever used them.
  • In a major clinical trial, treating hearing loss slowed thinking and memory decline by 48% over three years in older adults at higher risk of cognitive decline.
  • A hearing test is simple, and over-the-counter hearing aids now make treatment easier to get.

What the world’s leading dementia experts found

The Lancet Commission on dementia prevention, intervention, and care is an international panel of experts that regularly reviews the research on what drives dementia risk. Its 2024 update, presented at the Alzheimer’s Association International Conference, lists 14 modifiable risk factors: less education, hearing loss, high LDL cholesterol, depression, traumatic brain injury, physical inactivity, diabetes, smoking, high blood pressure, obesity, excessive alcohol use, social isolation, air pollution, and untreated vision loss.

Together, the Commission estimates, these factors account for about 45% of dementia cases worldwide, meaning nearly half could, in theory, be prevented or delayed.

Two of those factors stand out. Hearing loss and high LDL cholesterol, each measured in midlife, are each linked to about 7% of dementia cases, the largest share of any modifiable risk. High LDL was newly added in 2024, along with untreated vision loss.

Notice what’s missing from the top of the list: crossword puzzles, specific “brain foods,” and supplements. Staying mentally active across life does matter, especially through education, but the biggest single levers are more medical than most people expect.

Why hearing might affect the brain

Researchers don’t yet know exactly how hearing loss raises dementia risk, and it may work through several paths. One idea is that straining to understand speech forces the brain to divert resources away from memory and thinking. Another is that hearing loss leads people to withdraw from conversations and social life, and social isolation is itself a dementia risk factor. Hearing loss may also reduce stimulation to parts of the brain involved in processing sound.

What researchers are more confident about is the association. Observational studies have linked hearing impairment in older adults to faster cognitive decline and a substantially higher risk of developing dementia.

What happened when people’s hearing was treated

The strongest evidence comes from ACHIEVE, the largest randomized clinical trial of its kind, published in The Lancet in 2023. It followed 977 adults aged 70 to 84 with untreated mild-to-moderate hearing loss for three years. Half received hearing aids and counseling from an audiologist. The other half received a health education program.

Across the full group, the hearing intervention did not significantly change the rate of cognitive decline. But among 238 participants at higher risk of cognitive decline, who were older and had more risk factors such as heart disease, the hearing intervention slowed the loss of thinking and memory abilities by 48%.

That result suggests the benefit may be greatest for the people who need it most. The Lancet Commission concluded that the evidence that treating hearing loss lowers dementia risk is now stronger than it was in its previous report, and that hearing aids appear especially helpful for people with hearing loss plus other risk factors.

Why so many people don’t treat it

Hearing loss creeps in slowly, so many people don’t notice it or blame others for mumbling. According to the National Institute on Deafness and Other Communication Disorders, about 22% of adults 65 to 74 and 55% of those 75 and older have disabling hearing loss. Yet among adults 70 and older who could benefit from hearing aids, fewer than 1 in 3 have ever used them.

Cost and stigma have long been barriers. Since 2022, the FDA has allowed over-the-counter hearing aids for adults with perceived mild to moderate hearing loss, which can be bought without a prescription or an exam and generally cost less than traditional devices.

What to do with this information

Get a baseline hearing test, especially if you’re over 50, if people have commented on the TV volume, or if you struggle to follow conversations in restaurants. Your primary care doctor can refer you to an audiologist.

If you have hearing loss, treat it. Talk with an audiologist about prescription hearing aids, or consider over-the-counter devices if your hearing loss is mild to moderate. Wear them consistently. They only help if they’re in.

Protect the hearing you have. Limit exposure to loud noise and use ear protection with loud tools, concerts, or events.

Don’t forget the co-leader. Ask your doctor about your LDL cholesterol. It shares the top spot with hearing loss on the Commission’s list.

Keep the other habits too. Physical activity, blood pressure control, not smoking, and staying socially connected are all on the list. Brain games aren’t harmful. They just aren’t the whole story.

This article is for general information and isn’t a substitute for advice from your doctor.

Sources:

Adrienne Erin

Adrienne holds a Bachelor of Science in Kinesiology, where she developed a strong foundation in exercise physiology and human nutrition. Before joining DailyHealthPost, she spent several years writing about health and wellness topics, translating nutrition and fitness research into practical guidance for everyday readers.

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