Reuters Health - Parkinson disease may have become more common over the past 30 years, at least according to a study in one Minnesota county.
"This is the first evidence that shows an increasing trend of Parkinson incidence, confirmation is needed," said Dr. Honglei Chen of the National Institute of Environmental Health Sciences in Triangle Park, North Carolina, who wrote an editorial accompanying the new results.
Parkinson disease takes decades to develop, so it can be difficult to identify reasons for the trend and a number of factors may play a role, Chen said.
"However, if the trend is confirmed, one may speculate roles of environmental or other non-genetic factors," he told Reuters Health by email.
Senior author Dr. Walter A. Rocca of the Mayo Clinic in Rochester, Minnesota, and his coauthors studied trends in Parkinson disease and symptoms like resting tremors, rigidity, impaired reflexes and slowness of movement in Olmsted County, Minnesota, between 1976 and 2005.
