Study suggests lower dementia risk for people with Parkinson’s

There’s good news for people with Parkinson’s disease: The risk of developing dementia may be lower than previously thought, or dementia may occur later in the course of the disease than previously reported, according to a study published on August 7 2024 has been published online. matter of Neurology^®the medical journal of the American Academy of Neurology.

The development of dementia is feared by people with Parkinson’s, and the combination of both a movement disorder and cognitive impairment can be devastating for them and their loved ones. These results provide more hopeful estimates of the long-term risk of dementia for people with Parkinson’s disease, suggesting a longer window for intervention to prevent or slow cognitive decline.”

Daniel Weintraub, MD, study author from the University of Pennsylvania, Philadelphia

Previous studies had shown that approximately 80% of people with Parkinson’s disease would develop dementia within 15 to 20 years of being diagnosed with Parkinson’s.

“While these studies were important in highlighting the issue of cognitive decline in Parkinson’s disease, the studies were conducted many years ago, were relatively small, and had other limitations, so we wanted to re-evaluate these findings,” Weintraub said .

For the study, researchers analyzed data from two large, prospective studies. An international study involved 417 participants with an average age of 62 years who had recently been diagnosed with Parkinson’s disease and had not yet received treatment for the disease at the time of enrollment in the study. A study at the University of Pennsylvania involved 389 people with Parkinson’s, with an average age of 69 years, who had been diagnosed with Parkinson’s an average of six years before the start of the study. The participants were monitored to see if they developed dementia.

The international research shows that the risk of dementia ten years after the diagnosis of Parkinson’s disease is an estimated 9%. For the Pennsylvania study, the chance of being diagnosed with dementia 10 years after being diagnosed with Parkinson’s was 27%. For this latest study, researchers found an estimated risk of dementia of 50%, 15 years after Parkinson’s diagnosis, and 74%, 20 years after diagnosis.

Factors that increased the risk of dementia in the Pennsylvania study included being older when diagnosed with Parkinson’s, being male and having a lower level of education.

A limitation of both studies is that the participants were highly educated, primarily white people, and were recruited to participate in a study, so they may not represent the general population.

The international study, the Parkinson’s Progression Markers Initiative, is a public-private partnership funded by the Michael J. Fox Foundation for Parkinson’s Research and numerous funding partners. The University of Pennsylvania research was supported by the National Institute on Aging.