Pesticides can 'double' the risk of asthma

In the first study of its kind, scientists discovered adults who come into contact with pesticides are at a higher risk of developing respiratory problems.

The findings will further heighten concerns about the impact of chemical sprays on food and the proximity of schools and homes to farms where they are used.

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Last week, an official report showed 2 per cent of food sold in Britain contains illegal levels of chemical pesticides. Traces were also found in a third of fruit, vegetables, milk and meat.

Five million Britons suffer from asthma and the number is growing. The condition afflicts nearly a million children, around one in ten.

Past studies have linked asthma to second-hand tobacco smoke, poor diet and obesity. Traffic fumes and smoke have also been shown to worsen symptoms.

The study of 20,000 American farmers was presented yesterday at the European Respiratory Society's annual congress in Stockholm.

It found farmers who used the most pesticides were at the highest risk, even after their age, weight and smoking history were taken into account.

During the study, 452 farmers aged 30 and over developed asthma. Farmers in Iowa and North Carolina, who used around 16 chemical sprays, were found to be most at risk.

Although some of the sprays being used at the time have been withdrawn on U.S. and British farms, others - including the fungicide captan and the insecticide lindane - are still sprayed on crops.

Exposure to the pesticide coumaphos doubled the risk of a farmer suffering from asthma, the study added.

A spokesman for the researchers said: "The possible scope of the link between pesticides and adult-onset asthma raises a problem of broader interest, given the considerable quantities of pesticides used in the domestic and urban environments.

"Their impact on a population which, while less exposed, has a greater risk of allergies and a higher prevalence of asthma, remains to be determined."

Dr Noemi Eiser, of the British Lung Foundation, said: "Understanding what triggers someone's asthma attack can be immensely helpful when it comes to managing the condition.

"But it also emphasises how important it is for farmers to get themselves checked out and, if they have asthma, to always carry any necessary medication with them."

Lord Melchett, of the Soil Association, said: "There is something very rotten with the state of pesticide safety regulation.

"The Royal Commission on Environmental Pollution recently criticised the regulators for overstating the certainty of safety and ignoring the wide variety of scientific views."