A new research paper has been published in Aging-US titled “Age-related trends in amyloid positivity in Parkinson’s disease without dementia.”
A team of researchers, led by Keiko Hatano and Masashi Kameyama from the Tokyo Metropolitan Institute for Geriatrics and Gerontology in Japan, discovered that patients with Parkinson’s disease (PD) diagnosed in their 80s have a significantly higher rate of amyloid positivity—a marker linked to Alzheimer’s disease—compared to those diagnosed at a younger age. Notably, all participants in the study were free from dementia. These findings imply that older PD patients may face a heightened risk of future cognitive decline and should undergo early screening for Alzheimer’s-related brain changes.
Amyloid-beta is a crucial marker of cognitive decline, typically associated with dementia. While the relationship between amyloid accumulation and PD with dementia is well established, its significance in individuals who haven’t yet exhibited cognitive issues is less clear. This study aimed to assess how age impacts amyloid buildup in patients with PD who show no signs of dementia.
The researchers evaluated data from 89 individuals with PD but without dementia. They categorized participants into two age groups: those diagnosed before age 73 (LOW group) and those diagnosed at 73 or older (HIGH group). Using cerebrospinal fluid samples, they measured amyloid-beta levels, a standard method for detecting early Alzheimer’s-related changes. The results indicated that 30.6% of the older group tested positive for amyloid, whereas only 10.0% of the younger group did.
“[…] we elucidated the prevalence of amyloid positivity in patients with PD without dementia, whose mean age at diagnosis was 80.2 years, using CSF Aβ42 levels.”
Interestingly, both age groups of Parkinson’s patients exhibited lower rates of amyloid positivity compared to cognitively normal individuals of the same age in the general population. This surprising finding suggests that PD might change how amyloid accumulates in the brain, potentially leading to a quicker transition from healthy cognition to dementia in these patients. The study also noted age-related connections with other biological markers of Alzheimer’s disease, such as tau protein levels.
As the world’s population ages and the number of older adults diagnosed with PD increases, recognizing early signs of cognitive decline becomes vital. These findings could enhance future screening strategies and aid in the development of therapies aimed at delaying or preventing dementia in individuals with Parkinson’s disease.
