According to the Alzheimer’s Association, almost two-thirds of Americans living with Alzheimer’s disease are women. For years, that was explained mainly by the fact that women live longer. Researchers now think the picture is more complex — and, importantly, that much of dementia risk can be influenced.
Why women are affected more
Longevity is part of it: age is the biggest risk factor, and women live longer on average.
But longevity doesn’t fully explain the difference. Researchers are investigating:
- The menopause transition. Estrogen has effects on brain energy use and the brain’s response to injury and inflammation. Brain imaging studies have found changes in brain metabolism during the transition. How these changes relate to later dementia risk is an active area of research — and the answer isn’t yet clear.
- Genetics. The APOE4 gene variant, the strongest genetic risk factor for Alzheimer’s, appears to raise risk more in women than in men.
- Health conditions. Depression, which is more common in women, is a dementia risk factor. So are pregnancy complications such as preeclampsia, which are linked to later vascular problems.
- Historical factors. Lower access to education for women in older generations may have reduced “cognitive reserve” — the brain’s resilience to damage.
What you can influence
In 2024, the Lancet Commission on dementia prevention identified 14 modifiable risk factors across the lifespan and estimated that addressing them could potentially prevent or delay around 45% of dementia cases. That’s a population-level estimate, not a guarantee for any individual — but it’s a powerful signal that dementia isn’t simply fate.
The factors most relevant in midlife:
Hearing loss
Untreated hearing loss in midlife is one of the largest modifiable risk factors identified. Hearing aids appear to reduce the associated risk. If you’re struggling to follow conversations, get your hearing tested.
High LDL cholesterol
Added in the 2024 report: higher LDL cholesterol in midlife is associated with increased dementia risk. Cholesterol often rises after menopause, making this especially relevant for women.
High blood pressure
Treating midlife hypertension — aiming for a systolic pressure of 130 or below from around age 40 — is associated with lower dementia risk.
Physical inactivity
Regular exercise is consistently associated with lower risk of cognitive decline.
Diabetes and obesity
Both are linked to higher risk. Blood sugar control matters for the brain as well as the body.
Smoking and alcohol
Smoking raises risk; stopping at any age helps. Drinking more than around 21 units a week is associated with higher risk.
Depression
Treating depression may help protect the brain as well as improve quality of life.
Social isolation
Staying socially connected is associated with lower risk, possibly by building cognitive reserve and reducing stress.
Vision loss
Also added in 2024: untreated vision loss is associated with higher risk. Regular eye checks and treating conditions such as cataracts matter.
Air pollution and head injury
Protecting your head during sport and cycling, and reducing exposure to air pollution where possible, round out the list.
What about hormone therapy?
Whether menopausal hormone therapy protects against dementia is unresolved. The Women’s Health Initiative memory study found increased dementia risk when hormone therapy was started at 65 or older. Some observational studies suggest a possible benefit when started around the time of menopause, but trials haven’t confirmed this. Current guidance is that hormone therapy should not be used specifically to prevent dementia.
Practical steps for your 40s and 50s
- Check your blood pressure and cholesterol, and treat them if they’re high.
- Get your hearing and vision tested.
- Move most days, including strength training.
- Don’t smoke, and keep alcohol low.
- Protect sleep, and get help for sleep apnea, insomnia or depression.
- Stay connected and keep learning.
When to see a doctor
Midlife brain fog is common and usually temporary. But see a clinician about memory changes that are getting steadily worse, getting lost in familiar places, trouble managing finances or daily tasks, or changes in personality. Many causes of cognitive symptoms — thyroid problems, vitamin B12 deficiency, depression, sleep apnea, medication side effects — are treatable.