NEW evidence that exposure to pesticides may be linked to the development of Parkinson’s disease has come from a study in the US.

A team from Harvard School of Public Health found that people who said in 1992 that they had been in contact with pesticides were 70 per cent more likely to develop Parkinson’s within the next 10 years.

The finding, published in Annals of Neurology, carries more conviction than earlier claims because the participants were questioned about their exposure to pesticides long before they developed the disease.

When people are questioned after a diagnosis has been made, their answers are often unreliable. They may have heard suggestions of such a link, which colours their recollection of previous exposure.

A team led by Alberto Ascherio used data from a study of the link between diet and cancer, begun in 1992. Of the volunteers who filled in the original data, 143,325 responded in 2001 to a follow-up survey to see how they had fared.

Of these, 413 had developed Parkinson’s since the start of the study. Among the original questions had been one about exposure to pesticides, to which 5,203 men and 2,661 women had said yes.

Analysing the results, the team found that those who said that they had been exposed to pesticides were 70 per cent more likely to have developed the disease — after age, sex, and other risk factors were taken into account.

Previous studies had suggested that such a link existed, but were inconclusive. The authors of the new study conclude that the link is probably real, and needs further research to see which pesticide or class of pesticide is involved.

Georgina Downs of the UK Pesticides Campaign said: “Considering many pesticides are toxic to the nervous system, then it isn’t surprising that study after study has found associations with various chronic neurological and neuro-degenerative diseases such as Parkinson’s.

“The Government and the EU must take immediate action. The only way to protect public health and prevent any illnesses that could be associated with pesticides is to avoid exposure altogether through the widespread adoption of truly sustainable non-chemical natural methods.”

GRIM DIAGNOSIS

Parkinson’s disease is caused when two chemical messengers in the brain, dopamine and acetylcholine, which usually help to transmit messages between nerve cells and muscles, get confused

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