Parkinson’s disease risk increases with metabolic syndrome, study finds        

Having a larger waistline, high blood pressure and other risk factors that make up metabolic syndrome is associated with an increased risk of Parkinson’s disease, according to a new study.

The study does not prove that metabolic syndrome causes Parkinson’s disease; it only shows an association.

Metabolic syndrome is defined as having three or more of the following risk factors: excess belly fat, high blood pressure, high blood sugar, higher than normal triglycerides, which are a type of fat found in the blood, and low high-density lipoprotein (HDL) cholesterol, or “good” cholesterol.

Study author Weili Xu, PhD, of the Karolinska Institutet in Stockholm, Sweden, said: “Parkinson’s disease is the second most common neurodegenerative disorder among older adults after Alzheimer’s disease, and metabolic syndrome affects an estimated one in four adults and is highly modifiable.

“Our findings suggest that metabolic syndrome may be a modifiable risk factor for Parkinson’s disease.

“Future studies are needed to see whether working to control metabolic syndrome could help prevent Parkinson’s disease.”

The study involved 467,200 people with an average age of 57; of those 38 per cent had metabolic syndrome.

The participants were followed for a median of 15 years.

During that time, 3,222 people developed Parkinson’s disease.

For people without metabolic syndrome, the incidence rate for Parkinson’s was 4.87 cases per 10,000 person-years, compared to 5.21 cases per 10,000 person-years for people who had metabolic syndrome.

Person-years represent both the number of people in the study and the amount of time each person spends in the study.

After adjusting for age, smoking status, physical activity and genes that increase the risk of Parkinson’s disease, researchers found that people with metabolic syndrome were about 40 per cent more likely to develop Parkinson’s disease than people without the syndrome.

The researchers also conducted a meta-analysis of all studies on this topic and confirmed the finding that people with metabolic syndrome have an increased risk of Parkinson’s disease. Combining the current study with eight previous studies, the researchers found that people with metabolic syndrome were 29 per cent more likely to develop Parkinson’s disease than people without the syndrome.

“We also found a higher risk of Parkinson’s disease for people with both metabolic syndrome and a genetic susceptibility for Parkinson’s disease,” Xu said.

“This suggests that maintaining metabolic health may be especially important for people who have genes that increase their risk for Parkinson’s disease.”

A limitation of the study was that most of the participants were white people, so the results may not be the same for other groups.