Women with Parkinson's disease carry a heavier burden of Alzheimer's-related amyloid plaque in the brain than men do, according to findings from Mayo Clinic Arizona presented at the European Academy of Neurology Congress 2026. The team examined 230 autopsy-confirmed Parkinson's cases from the Arizona Study of Aging and Neurodegenerative Disorders and Brain and Body Donation Program, in which participants were assessed clinically each year while alive and underwent detailed neuropathological examination after death.
The sex difference showed up on two separate measures. Women averaged a cortical total plaque score of 6.5 out of 15 compared with 4.9 for men, and their neuritic plaque density averaged 1.7 out of 3 versus 1.3 for men. Both differences reached statistical significance, though the margins were modest.
The two diseases often overlap in older adults, and that overlap matters clinically: Alzheimer's pathology layered on top of Parkinson's tends to shape how cognition declines. Yet, as the researchers note, sex differences in Alzheimer's-related changes among people with Parkinson's have received little attention. If women with Parkinson's are systematically accumulating more amyloid, that could inform how clinicians anticipate cognitive symptoms and how future trials of amyloid-targeting drugs are designed and stratified.
This is autopsy-based observational work drawn from a single donation program, and it was presented at a scientific meeting rather than published as a full paper, so the finding needs confirmation in other cohorts before it changes practice. What it does establish is a concrete reason to look harder at sex as a variable in the Parkinson's-Alzheimer's overlap.