Women with Parkinson’s disease may be more susceptible to Alzheimer-type brain changes than men, as suggested by new data presented at the EAN Congress 2026. The findings stem from a neuropathological study of patients with autopsy-confirmed Parkinson’s disease.
The Connection Between Parkinson’s and Alzheimer’s Disease
Parkinson’s and Alzheimer’s diseases frequently occur together, particularly in older age. However, little is known about whether Alzheimer-associated brain changes differ between men and women with Parkinson’s. Researchers from the Mayo Clinic Arizona analyzed data from 230 autopsy-verified Parkinson’s patients, collected as part of the Arizona Study of Aging and Neurodegenerative Disorders and the Brain and Body Donation Program. Participants were clinically assessed annually during their lifetimes, followed by a comprehensive neuropathological analysis post-mortem.
Higher Amyloid Plaque Load in Women
The analysis indicated that women were significantly more affected by amyloid deposits than men. Amyloid plaques are one of the hallmark features of Alzheimer’s pathology. The average cortical total plaque score for women was 6.5 out of 15, compared to 4.9 for men (p = 0.045). Furthermore, the density of neuritic plaques was also higher in women than in men (1.7 vs. 1.3 out of 3 points; p = 0.035).
Moreover, over half of the female study participants displayed high plaque load, with a percentage of 56.8%, whereas for men, it was only 39.7% (p = 0.015).
Increased Risk Even After Adjustments
The difference remained significant even after accounting for potential influencing factors. After adjusting for age at death and the APOE-ε4 allele—a major genetic risk factor for Alzheimer’s dementia—the likelihood of having a high amyloid plaque load in women was more than twice that of men (OR 2.18; 95% CI 1.17–4.06; p = 0.014).
Lead researcher Dr. Erika Driver-Dunckley from Mayo Clinic Arizona noted parallels with observations in Alzheimer’s patients. The results may indicate that women possess increased susceptibility to amyloid-driven pathological processes within the context of Parkinson’s disease.
No Differences in Dementia and Cognition
Surprisingly, despite the greater amyloid burden, the researchers found no significant differences in clinical endpoints. The prevalence of Alzheimer’s dementia was comparable between men and women. Neuropsychological testing also revealed no gender-specific differences.
This result is unexpected, as higher plaque burden is generally associated with an increased risk of cognitive impairment. The authors speculate that the sample size may not have been sufficient to reliably detect potential differences in cognitive performance.
Unanswered Questions About Biological Mechanisms
The reason why women with Parkinson’s seemingly develop Alzheimer-associated amyloid changes more frequently remains unclear. Previous studies on Alzheimer’s patients without Parkinson’s have already identified gender-specific differences in brain atrophy, neuropathological burden, and cognitive impairments.
The current data suggests that biological factors may play a role. Future large-scale clinicopathological studies should confirm these findings and further investigate the underlying mechanisms.
Clinical Significance of the Findings
This study provides new insights suggesting that gender-specific differences in neurodegenerative diseases should be more rigorously considered. Whether the increased amyloid plaque load in women is associated with a higher long-term risk of cognitive decline remains to be determined in further research. Currently, the existing data show significant differences in brain pathology but not in clinical outcomes.
