Patients with type 2 diabetes are more likely to develop Parkinson’s disease, although the reasons are unclear, Finnish researchers reported on Wednesday.

They found that people with type 2 diabetes were 83 percent more likely to be diagnosed with Parkinson’s later in life than people in the general population. This risk was the same for men and women and was independent of other risk factors.

“Diabetes might increase the risk of Parkinson’s disease partly through excess body weight,” the researchers wrote in the April issue of Diabetes Care.

Being overweight and not exercising enough are linked with type 2 diabetes, which is becoming more common around the world. Diabetes can lead to blindness, limb loss, heart disease and early death.

Parkinson’s is a movement disorder caused by the destruction of certain brain cells. People often develop tremors first, but the incurable disease can progress to paralysis and death.

There are no known major risk factors for Parkinson’s, but some studies suggest exposure to chemicals such as pesticides may cause some cases. It affects about 1 million people in the United States alone.

Dr. Gang Hu and colleagues at the National Public Health Institute in Helsinki, Finland, followed 51,552 Finnish men and women aged 25 to 74 for 18 years. None had Parkinson’s disease at the beginning of the study.

About 600 developed Parkinson’s by the end of it, and those who did were nearly twice as likely to have diabetes as well, the researchers found.

They said they would investigate the link further.

SOURCE: Diabetes Care, April 2007.