The data came from 3,637 Parkinson's patients and an equal number of people without Parkinson's disease. All participants live in the U.K., and almost all of the Parkinson's patients -- 90% -- were diagnosed after age 60.
The researchers checked participants' prescription records and found that Parkinson's disease was almost 25% rarer in current, long-term users of calcium channel blockers.
Age and sex didn't affect the results. But the researchers -- who included Claudia Becker, PhD, of Switzerland's University Hospital Basel, couldn't adjust for other factors including level of education, socioeconomic status, and cholesterol levels.
The study appears online in Neurology.