The world’s leading dementia research commission ranks hearing loss among the largest modifiable risk factors.
In 2024, the Lancet Commission on Dementia Prevention, Intervention, and Care — the most authoritative ongoing review of dementia science in the world — published its latest report identifying 14 modifiable risk factors that together account for approximately 45% of global dementia cases.
Hearing loss ranked among the largest of all 14, accounting for an estimated 7% of global dementia cases — more than physical inactivity, obesity, smoking, diabetes, or depression individually.
Why hearing loss damages the brain
The connection between hearing loss and cognitive decline runs through four distinct mechanisms.
Increased cognitive load. When hearing is impaired, the brain must work significantly harder to decode speech and environmental sound. Cognitive resources that would otherwise be available for memory encoding, executive function, and attention are diverted toward basic auditory processing. Over years and decades, this chronic overallocation of cognitive resources accelerates decline.
Sensory deprivation and brain atrophy. Reduced auditory input from the environment directly affects brain structure. People with untreated hearing loss show measurably reduced temporal lobe volume on MRI — including in regions directly involved in memory and language. Auditory deprivation causes the neural networks that process sound to reorganize and atrophy, and the damage extends into adjacent cognitive regions. The brain shrinks where it stops receiving input.
Social isolation and withdrawal. Hearing loss makes conversation effortful and often embarrassing. People pull back from dinner tables, from social events, and from phone calls. Social isolation is itself one of the 14 Lancet Commission risk factors for dementia, independently of hearing. Untreated hearing loss can trigger both simultaneously, compounding the cognitive cost of each.
Depression and reduced cognitive reserve. Chronic communication difficulty is associated with depression in older adults, and depression is another of the 14 Lancet Commission risk factors. Hearing loss leads to social withdrawal, social withdrawal leads to depression, depression depletes cognitive reserve, and reduced cognitive reserve accelerates the clinical expression of underlying neurological changes.
What happens when hearing loss is treated
The ACHIEVE trial — the largest randomized controlled trial of hearing intervention for cognitive protection ever conducted — was published in The Lancet in July 2023. The trial enrolled 977 adults aged 70 to 84 with untreated mild-to-moderate hearing loss and followed them for three years.
In the overall trial population, the hearing intervention did not significantly outperform the control group. But when researchers focused on the pre-specified subgroup of participants who were at higher risk for cognitive decline — older adults with more cardiovascular risk factors and faster baseline rates of cognitive change — hearing intervention slowed cognitive decline by 48% over three years.
A separate 2023 meta-analysis combining data from more than 137,000 participants found that hearing aid use was associated with a 19% lower risk of long-term cognitive decline across studies with follow-up periods ranging from two to twenty-five years.
The research doesn’t prove that treating hearing loss prevents dementia. What it does establish is a consistent, biologically plausible association — confirmed across multiple study designs — between untreated hearing loss and accelerated cognitive decline, and between hearing intervention and slower decline in higher-risk populations.
A risk factor most people haven’t checked since grade school
Age-related hearing loss develops gradually — often over years — and most people adapt to it without realizing how significant the change has become. Unlike blood pressure or blood sugar, hearing loss doesn’t trigger a warning signal. It gets rationalized away — gradually, invisibly, over years.
The Lancet Commission’s recommendation is direct: make hearing aids accessible for people with hearing loss and decrease harmful noise exposure to prevent it. Getting a hearing assessment is the starting point — and it’s something adults over 50 are routinely encouraged to do — but rarely prioritize.
A standard audiological assessment is straightforward. Many primary care physicians can perform basic screening. A formal evaluation by an audiologist gives a complete picture of the type and degree of any loss and whether intervention is warranted.
“Hearing loss is the kind of risk factor that accumulates slowly for years before anyone notices. By the time it’s obvious, the cognitive cost has already been taking its toll. Hearing loss belongs in every brain health conversation. It is not an afterthought, but one of the more actionable things on the list.”
— Dr. Randy Pardue
The next VitalLife Brain Health Cohort starts soon.
The VitalLife Brain Health Cohort addresses the lifestyle-modifiable factors identified by the Lancet Commission — across nutrition, movement, sleep, and pursuit of peace — with Dr. Pardue’s clinical oversight and the VitalLife coaching team alongside you throughout.
If this email has raised questions, the Preview Night on August 25 is where you get them answered. No commitment, no obligation. Meet Dr. Pardue and the team, see the program, and decide whether it’s right for you.
The July cohort sold out at 30 participants.
→ Sign Up for the VitalLife program: SIGN UP
Free Preview Night
Meet Dr. Pardue and the team. See the program. Ask your questions. 6:30pm at Vital Wellness, 9965 Kingston Pike. → REGISTER FOR THE FREE PREVIEW NIGHT
For your health,
Adam (on behalf of Dr. Pardue)
P.S. If you’re over 50 and haven’t had a hearing assessment in the last few years, it’s worth scheduling one. Ask your primary care physician for a referral to an audiologist — it’s a step most people skip.
P.P.S If you are tech savvy, you can also take a validated clinical-grade hearing test using your iPhone and AirPod Pro headphones. I did it this morning. Takes about 5 minutes.