Asthma comes first, not allergy, study finds
Press reports suggest that allergies are a consequence of asthma, not a cause of it, the largest genetic study of the condition has concluded.
Scientists have found seven genes linked to the development of the ailment, which could lead to new treatments.
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Researchers from Imperial College London and colleagues around the world carried out more than half a million genetic tests on 26,000 subjects.
The findings, published in The New England Journal of Medicine, suggest that allergies are a consequence of asthma, which causes damaged airways.
They also found that adult-onset asthma and childhood asthma were different diseases.
But the head of respiratory and environmental epidemiology at the Woolcock Institute in Sydney, Guy Marks, said he did not think the study had definitively shown that allergies were a consequence of asthma, not the cause.
”That is the conclusion the authors have drawn but I would be a bit more cautious,” he said.
He believed this type of research – including other genetic studies of asthma being conducted among Australians – might lead to better-targeted treatments and ways to prevent asthma in the first place. Australian asthma rates were among the highest in the world, said the chief executive of the Asthma Foundation NSW, Michele Goldman.
About one in nine children and one in 10 adults had it. It was thought to be caused by a combination of genetic and environmental factors, Ms Goldman said.
This research highlighted that asthmatics were better off finding a medication that worked for them than trying to avoid potential allergens, she said.
The genes were found in a third of children with asthma. Some were involved in activating the immune system; others were linked to breathing. This means treatments could be designed to correct their function.
Professor William Cookson, of Imperial College London, who co-ordinated the research, said: ”Our study highlights targets for asthma therapies and suggests that therapies against these targets will be of use to many asthmatics.”
The researchers will now look for what causes damage to the airways and why some factors seem to protect against asthma.