The drugs may have a protective effect

However, while the study may provide clues to future therapies, doctors are not recommending people taking drugs such as ibuprofen long-term.

This is because long-term use may carry its own health risks.

Parkinson's is a progressive disease which leads to the death of brain cells key to the control of muscles.

Symptoms include uncontrollable shaking and rigidity.

In the UK, one in 500 people, around 120,000 individuals have Parkinson's. Usually symptoms appear after the age of 50 and the risk of getting Parkinson's increases with age.

Protection

Doctors believe that the anti-inflammatory effects of the painkillers, called NSAIDS, may help keep brain cells alive.

They found that the risk of Parkinson's was reduced by approximately 45% among adults who regularly took the drugs.

Those who took two or more aspirin daily also received a protective effect from Parkinson's.

The study involved records from more than 140,000 people from two large trials.

Six percent of the men and four percent of the women regularly used NSAIDs, and from this group, 415 cases of Parkinson's disease were diagnosed.

The research was published in the Journal Archives of Neurology.

Dr Honglei Chen, from Harvard Medical School, said: "The results of post-mortem studies suggest that inflammation is involved in the development of Parkinson's disease and there is experimental evidence that NSAIDS are protective for the cells that are selectively destroyed."

Researchers suggested that the finding might eventually help refine existing treatments for Parkinson's.

However, there is no recommendation for people to start taking NSAIDS long-term in order to reduce their chances of developing the disease.

Taking the drugs in this way comes at a price - an increased risk of potentially dangerous stomach ulcers.

A recent study suggested that taking NSAIDS early in pregnancy substantially increased the risk of miscarriage.