Brain
What we know
Across the world, affects women disproportionately, even after accounting for the fact that women live longer.1 Researchers are still working out why.
Brain fog, meaning trouble with memory and concentration, is a common symptom of perimenopause.2 It's different from dementia.
Hormone therapy and dementia
Myth: Hormone therapy protects against dementia, or causes it.
Both claims have been widely reported, so it's no wonder people are unsure. A 2025 review commissioned by the WHO, covering more than a million people, found no clear link either way between menopause hormone therapy and or , whatever the timing, length or type of treatment.1 Much of the evidence is of low certainty, and more long-term research is needed. For now, hormone therapy is chosen for its benefits and risks for symptoms, not for dementia prevention.1
Losing ovarian function before 40 is different: premature ovarian insufficiency is linked to a higher risk of cognitive impairment and dementia, which is one reason hormone therapy is recommended until the usual age of menopause.3
What lowers the risk
The 2024 Lancet Commission on estimated that about 45% of future dementia could potentially be prevented if 14 risk factors were eliminated:4
- less education early in life
- hearing loss
- untreated vision loss
- high LDL cholesterol in midlife
- high blood pressure
- diabetes
- obesity
- smoking
- excessive alcohol
- physical inactivity
- depression
- social isolation
- traumatic brain injury
- air pollution
Many of these are things a doctor can check and treat, like hearing, vision, blood pressure and cholesterol.
When to see a doctor
See a doctor if problems with memory or thinking are getting worse, or start to affect daily life.
Recap
- Dementia affects women disproportionately, even after accounting for longer lifespans.
- A 2025 review of over a million people found menopause hormone therapy doesn't appear to raise or lower dementia risk.
- Hormone therapy is used for symptoms, not to prevent dementia.
- About 45% of dementia might be prevented by addressing 14 risk factors, including hearing loss, high LDL cholesterol, high blood pressure, inactivity and social isolation.
Words to know 2
| dementia | A decline in memory, thinking and daily functioning severe enough to affect everyday life. Alzheimer's disease is the most common type. |
|---|---|
| mild cognitive impairment | Changes in memory or thinking that are more than expected for age but don't stop someone from managing daily life. |
Educational information, not medical advice. Talk to your doctor about your health.