A study published in the scientific journal Neurology sheds new light on how diabetes affects Parkinson's disease risk. While the association between the two diseases was known, this study adds to our understanding of who is most at risk.

Researchers at University College London examined records of more than 8 million people admitted to British hospitals over a 12-year period. They found that people with type 2 diabetes have a 31 percent greater risk of developing Parkinson's than people without diabetes. But that rose to 49 percent greater risk for people experiencing complications from their diabetes and 400 percent for younger people (ages 25-44) with the disease. It's important to note that healthy people are at very low risk of developing Parkinson's during their life time, so the higher risk for people with diabetes compared to them is still relatively low.

The study authors didn't examine how diabetes may contribute to Parkinson's, but prior research does offer clues. We know that neurons consume much more energy than other cells in our bodies. Mitochondria, the powerhouses of our cells, convert glucose into useable energy for cells. In Parkinson's and other neurodegenerative diseases, mitochondria can become dysfunctional, which may damage and eventually kill our neurons. Dopaminergic neurons -- the type involved in Parkinson's -- are particularly vulnerable to mitochondrial dysfunction. Diabetes appears to contribute to this, as can some genetic factors.

Though research is ongoing, The Michael J. Fox Foundation is already funding clinical trials of potential treatments. Last year, MJFF-funded investigators published initial positive findings from a Phase II trial of exenatide, a diabetes drug classified as a GLP-1 agonist. And our partners at the The Cure Parkinson's Trust in the UK are supporting trials of two other GLP-1 agonists, liraglutide and lixisenatide, in Parkinson's patients. MJFF is also funding the development of new and improved mitochondrial biomarkers; these tools will help researchers better understand the role of mitochondria in Parkinson's and how GLP-1 agonists and other drugs affect them. Sign up for Fox Trial Finder to be matched with recruiting Parkinson's clinical trials.