11,925 older women in four studies: the stronger the blood protein signature of menopause, the more cognitive ageing and dementia risk. The protein changes tracked hormones more than age. It is a link, not a test or a cause.
The other side A 2025 review of over a million women found hormone therapy neither raised nor lowered dementia risk, so this study is not evidence that hormone therapy protects the brain. Lancet Healthy Longevity, 2025