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Why Obese Are More Prone To Asthma
Researchers say they may have worked out why the
obese are more prone to asthma than those of normal weight.
The link between the two conditions is well-established,
but the relationship is ill-understood.
Now scientists at King's College London say they
have pinned down a protein which contributes to inflammation of
the lungs as well as increasing hunger.
The study in the Proceedings of the National
Academy of Sciences said further research was now needed.
Mechanism mystery
The researchers investigated molecules produced
by Th2 cells - specialised cells belonging to the immune system
which can inflame the lungs and contribute to the development
of asthma.
But these cells also produce a protein known
as PMCH which is known to increase appetite.
"These findings may provide a mechanistic link
between allergic inflammation, asthma and obesity," the researchers
wrote.
Several European and American studies have found
a link between obesity and asthma which cannot be explained by
weight gain brought on by the inactivity asthma encourages. In
many cases, the obesity precedes the asthma.
One study of 330,000 patients published earlier
this year found that for every normal weight person with asthma,
there were 1.5 who were overweight or obese.
The latter category effectively ran a 50% greater
risk of developing the condition.
However, people with asthma are not always obese,
so the lead researcher of this latest study, Dr David Cousins,
said further investigation was needed into possible genetic variations
of PMCH, the gene known to boost appetite.
Dr David Haslam of the National Obesity Forum
said that from the obesity perspective, the research was interesting
although as yet there were no therapeutic implications.
"Working out the mechanisms, the links between
diseases is important, and it adds to the growing body of evidence
which gives obesity some form of genetic basis."
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