Common Diabetes Drugs Linked to Lower Risk of Parkinson’s Disease

A class of Type 2 diabetes drugs known as glitazones may decrease the risk of developing Parkinson’s disease, according to new research out of the London School of Hygiene & Tropical Medicine. Approximately 28 million people in the United States have Type 2 diabetes, and roughly one million Americans have Parkinson’s.

Glitazones, also called thiazolidinediones or TZDs, work by lowering insulin resistance in muscle and fat cells and also by decreasing glucose production in the liver. The medicines function by activating a receptor (a gatekeeper embedded in cell walls) known as peroxisome proliferation-activated gamma, which has multiple functions in the body, not all of which are understood. Previous laboratory and animal studies have indicated that glitazones may prevent the loss of nerve cells.

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To determine whether the protective effects of glitazones, which include rosiglitazone (brand name Avandia) and pioglitazone (Actos), are present in humans, researchers looked at the electronic health records of more than 160,000 people with diabetes in the United Kingdom spanning a period from 1999 to 2013. Of these subjects, 44,597 were taking glitazones and 120,373 were using other diabetes drugs.

They found that people taking a glitazone had a 28% lower incidence of Parkinson’s disease than those taking other types of diabetes treatments who had never taken glitazones, even taking into account other factors that might affect Parkinson’s risk, such as smoking and head injury. The researchers also found that the medicines did not have a lasting protective effect against Parkinson’s — there was no benefit those who had used them previously and then switched to other diabetes drugs.

The finding is “an exciting development because it suggests that glitazones may prevent the onset of Parkinson’s disease in patients with diabetes,” according to diabetes expert Minisha Sood, MD.

The study authors note that these drugs can be associated with potentially serious side effects, such as increased risk of heart failure, and that the study can’t prove cause and effect. The study also was not intended to determine whether glitazones can slow the progress of Parkinson’s once a person has been diagnosed with the condition.

“Our findings provide unique evidence that we hope will drive further investigation into potential drug treatments for Parkinson’s disease,” said senior study author Ian Douglas, PhD, MSc, BSc.

For more information, read the article “Diabetes drug may reduce risk of developing Parkinson’s disease” or see the study in the journal PLOS Medicine. And for more information about the glitazone class of medications, read this piece by clinical pharmacologist Mark Marino.