An asthma medication may help prevent Parkinson's disease, finds a new study from Harvard researchers.

With early funding from The Michael J. Fox Foundation, scientists looked for drugs that would lower expression of the alpha-synuclein gene. Researchers believe these drugs could prevent clumping of alpha-synuclein protein, the hallmark of Parkinson's.

One drug they found is called salbutamol, which is used to treat asthma. Partnering with the University of Bergen in Norway, the Harvard researchers looked back at medical records to study any association between taking salbutamol and Parkinson's prevention.

"You need to have very large prescription databases with many years of follow-up to do this analysis," lead researcher Clemens Scherzer, MD, told Science magazine.

They found people who took salbutamol at least once were about one-third less likely to develop Parkinson's disease (PD).

What's next? This is a strong lead on how to prevent PD, but researchers may have to tweak them to be most effective for Parkinson's with fewest side effects. Scientists will keep working to move the best possible drug into clinical trials.

There are five therapies currently in clinical trials acting against alpha-synuclein. Read more for the latest on those studies.

These findings are another example of potential drug repurposing -- naming a biological pathway associated with PD, finding a drug already acting on that pathway, studying people who take that drug for any relationship to Parkinson's. Read more on other repurposed drugs in testing for PD.