Women with Parkinson's have higher rates of Alzheimer's pathology

A new study is shedding light on how changes associated with different neurodegenerative diseases can overlap in the brain - and how that overlap may differ between women and men.

The study was published in the Journal of Parkinson's Disease. Through the Arizona Study of Aging and Neurodegenerative Disorders (AZSAND) and Brain and Body Donation Program (BBDP), researchers studied 230 autopsy cases of people with Parkinson's disease, looking for differences between sexes.

What we found was, in women, particularly those with Parkinson's disease dementia, they had higher rates of Alzheimer's amyloid pathology."

Erika Driver-Dunckley, M.D., one of the lead researchers and movement disorder neurologist, Mayo Clinic

Amyloid is a protein that can build up into sticky plaques in the brain. Those plaques are one of the hallmark brain changes associated with Alzheimer's disease.

Finding signs of more than one neurodegenerative disease in the same brain wasn't necessarily surprising to the researchers.

"A lot of patients have mixed pathologies, which means they may have been brought into the brain bank with one diagnosis, but then after we do autopsy studies, we actually identify they have multiple neurodegenerative diseases," Dr. Driver-Dunckley says. "It's not unusual for us to find mixed pathologies. The sex difference is what was interesting to us."

Researchers found women had higher rates of Alzheimer's amyloid pathology, but they did not find a difference between women and men in tau pathology or levels of cognitive impairment.

Researchers say the findings could help scientists better understand the relationship between Parkinson's and Alzheimer's disease and potentially identify new areas for treatment research.

Anti-amyloid medications are already approved for certain patients diagnosed with Alzheimer's disease. Dr. Driver-Dunckley says the new findings in the study raise the possibility of studying whether those treatments could someday benefit certain patients with Parkinson's disease dementia who also have increased amyloid pathology.