Diabetes patients at increased risk for Parkinson's disease

Type 2 diabetes patients are at an increased risk of developing Parkinson's disease (PD) later in life, according to a retrospective cohort study published in the journal Neurology. In addition, the risk may be higher for younger people and those with complications from the disease.

The study was conducted by Thomas T. Warner, University College London (UCL) in the United Kingdom, and colleagues to investigate the association between type 2 diabetes mellitus (T2DM) and subsequent PD.

Parkinson's is a progressive disease that affects a brain part responsible for controlling movements. In T2DM, a person doesn't make sufficient insulin required for converting blood sugar into energy or the insulin is not used by the cells efficiently.

"Our study examined data on a large portion of the English population and found a strong link between these two seemingly different diseases," said Warner. "Whether it is genetics that may play a role in the development of these diseases or they have similar pathways to development needs to be investigated further."

For the study, researchers looked at data in a nationwide hospital database in England over 12 years and identified more than 2 million people who were admitted to the hospital for T2DM for the first time. They were then compared to more than 6 million people without diabetes who were admitted to a hospital for a range of minor medical and surgical procedures like sprains, varicose veins, appendectomy and hip replacement.

Key Findings:

• Of the more than 2 million people with T2DM, 14,252 had a diagnosis of PD during a later hospital admission, compared with 20,878 of the more than 6 million people without T2DM who were later diagnosed with Parkinson's.


• After excluding conditions known to mimic PD, and adjusting for age, sex, where participants lived, the frequency of hospital admissions and duration of follow-up, researchers found that those with T2DM had a 31 percent greater risk of a later diagnosis of Parkinson's disease than those without diabetes.


• The risk of being diagnosed with Parkinson's disease later in life was even higher for younger people, ages 25 to 44. In that group, 58 of 130,728 people developed Parkinson's, compared with 280 of 2,559,693 in the group of people without diabetes.


• Among those who were 75 and older, there were 7,371 people out of 664,709 people with diabetes who developed Parkinson's, compared with 10,105 out of 752,104 in the group of people without diabetes, which after adjustment amounted to an 18 percent greater risk than for those without diabetes.


• Those with complications from diabetes had a 49 percent greater risk of a later diagnosis of Parkinson's disease than people without the disease.


• Those without diabetes complications were 30 percent more likely to develop Parkinson's than those without the disease.

"Restoring the brain's ability to use insulin could potentially have a protective effect on the brain," said Warner. "It is possible that a link between T2DM and Parkinson's could affect future diagnosis and treatment of these diseases."

One limitation of the study was that researchers were unable to adjust results for medication and smoking. Also, because it was a hospital-based study, it is possible those diagnosed with diabetes may have had a more severe form of the disease than those who are diagnosed in a clinic.

"We report an increased rate of subsequent PD following T2DM in this large cohort study. These findings may reflect shared genetic predisposition and/or disrupted shared pathogenic pathways with potential clinical and therapeutic implications," concluded the authors.

For more information click on the link: https://doi.org/10.1212/WNL.0000000000005771