Metabolic syndrome tied to higher Parkinson's dementia risk: Study

31 Oct 2024, 15:00 by Lindsey Shapiro, PhD · Parkinson's News Today

Metabolic syndrome, a cluster of conditions that can increase the risk of heart disease, diabetes, and stroke, is associated with a higher risk of developing dementia in people with Parkinson’s disease, according to recent research.

“These findings advocate for comprehensive management of MetS [metabolic syndrome] as a pivotal strategy to alleviate cognitive and non-motor burdens in PD [Parkinson’s],” researchers wrote. “Further research is needed to investigate underlying mechanisms and to formulate targeted interventions addressing the metabolic dimensions of PD.”

The study, “Increased dementia risk in patients with Parkinson’s disease attributed to metabolic syndrome,” was published in Neurological Sciences.

A substantial proportion of Parkinson’s patients experience cognitive issues in some form. While this can start off as mild cognitive impairment, where there are memory or thinking problems but they aren’t overly disruptive, some patients will eventually develop dementia, in which cognitive dysfunction significantly interferes with daily life.

Various factors have been associated with dementia risk in Parkinson’s, including older age, disease severity, and lower education levels.

Metabolic syndrome raises risk of heart disease, stroke, diabetes

Metabolic syndrome refers to a group of conditions that increase the risk of cardiovascular disease, type 2 diabetes, or stroke. To be considered to have metabolic syndrome, a person would have three of the following: excess belly fat, high blood pressure, high blood sugar, elevated blood triglycerides (a type of fat), or low blood levels of HDL, sometimes referred to as “good” cholesterol.

There’s some overlap between Parkinson’s and metabolic syndrome, as both cause inflammation and oxidative stress, a type of cellular damage. Previous research has linked metabolic syndrome to Parkinson’s progression and risk.

Individual metabolic factors, such has diabetes and high blood sugar, have been associated with worse cognition in Parkinson’s. Moreover, research in the general population has found metabolic syndrome overall to be a risk factor for mild cognitive impairment and its progression to dementia.

In the new study, researchers in Turkey examined the potential relationship between metabolic syndrome and dementia among 134 early-stage Parkinson’s patients seen at their outpatient clinic. Patients, with a mean age of about 65 years, had been living with Parkinson’s for a mean of around five years.

Metabolic syndrome was present in more than a third of participants (39.6%), and nearly half (48.9%) were classified as having dementia based on the Montreal Cognitive Assessment (MoCA) scale. The remaining patients had normal cognition (22%) or mild cognitive impairments (29.1%).

People with metabolic syndrome were found to have a significantly higher burden of nonmotor symptoms and lower average MoCA scores than those without it. People with dementia were significantly older than those with normal cognition.

Higher blood sugar levels correlated with worse cognitive scores

Some relationships were identified between aspects of metabolic syndrome and cognition. For example, there was an inverse relationship between blood sugar and cognition, where higher blood sugar levels were correlated with worse cognitive scores in certain MoCA domains, namely visual/spatial and executive function, naming, language, and orientation.

Final statistical analyses indicated patients with metabolic syndrome could be at up to an 11 times higher risk of dementia than those without it. Older age was associated with a similar risk.

There are a number of mechanisms through which metabolic factors might influence Parkinson’s, according to the researchers. For example, they can lead to inflammation or blood flow changes in the brain that further damage nerve cells.

The findings in this group of Parkinson’s patients are generally similar to observations in other neurodegenerative diseases like Alzheimer’s disease, where proper management of metabolic syndrome has been associated with a reduced risk of dementia.

“These findings underscore the potential therapeutic benefits of managing components of MetS to mitigate the risks and progression of PD,” the researchers wrote, noting “medical therapies could be complemented by dietary modifications and exercise regimens for patients.”