New York: Plant pesticides and weedkillers more than doubles the risk increase the risk of Parkinson’s disease in later life, new research has revealed.

In the US study, partly founded by the Michael J Fox Foundation, scientists examined statistics on more than 140,000 men and women, Of the total, exposure to pesticides was reported by 7,864 participants, while there were 413 cases of Parkinson’s.

Taking into account age, sex and other factors such as diet and exercise, the researchers concluded that individuals who reported exposure to pesticides had a 70 per cent higher incidence of the disease than those who did not. The research is published in the Annals of Neurology.

While farmers were more likely to have been exposed, the development of Parkinson’s was equally prevalent among other workers.

Potential sources include crop spraying, weedkillers, pesticides and insecticides used in the garden and fly sprays and ant powders used in the home.

The researchers said they did not find any link between the amount of time the men and women had been exposed to the chemicals and the risk of Parkinson’s. Nor was there any increased risk from exposure to other occupational hazards, including asbestos, coal or stone dust, chemicals, acids or solvents.

They concluded that the hypothosis that exposure to pesticides is a risk factor for Parkinson’s disease.

Actor Fox was diagnosed with the disease in 1991 at the peak of his Hollywood success. He established the foundation to fund research into the disease

No specific chemicals or pesticides were named in the study and the researchers said more work was needed to examine which are likely to cause the condition.