Why ibuprofen has an effect on the development of Parkinson's is still unknown. Known risk factors for Parkinson's disease, such as age, gender and smoking status, could not explain the results.

"Our previous study, for the first time, showed that regular users of non-aspirin NSAIDs had a lower risk of Parkinson's disease than non-users," said lead author Honglei Chen, MD, PhD, of the Harvard School of Public Health and the National Institute of Environmental Health Sciences.

"There has been evidence suggesting a role of neuro-inflammation in the disease process, and our previous study indicated that non-aspirin NSAIDs might be protective," Dr. Chen added.

Risk Correlated with Dosage

Ibuprofen users had a 35 percent lower risk of Parkinson's disease, according to the latest findings, and the results were similar in both men and women.

Out of 146,948 participants, the study identified a total of 413 cases of Parkinson's disease. The participants were tracked over the course of an average 8.5 years.

The risk of disease onset seemed to decrease depending on the weekly dosage. The risk was 38 percent lower for people who took a daily ibuprofen tablet, compared to people who did not take ibuprofen regularly.

Mechanism Remains Cloudy

Why ibuprofen has an effect on the development of Parkinson's is still unknown.

"The mechanisms as to why ibuprofen protects against the disorder are not clear, and this is the area where we need more research," said Dr. Chen.

Known risk factors for Parkinson's disease, such as age, gender and smoking status, could not explain the results.

No significant links to the risk of Parkinson's disease were found with the use of aspirin, other NSAIDs or acetaminophen.