Asthma is 'highly heritable'

The UK has one of the highest asthma rates

A study of twins in England and Wales has found that asthma is primarily an inherited genetic disease.

The report concluded that genes are 68% responsible for asthma in young children, compared to environmental influences which only account for 13%.

The research was carried out by doctors at the Institute of Psychiatry in London and the University of Southampton.

It is the first study to examine genetic influences on asthmatic pre-school children.

Diet 'minor'

The researchers said: "The present findings indicate that asthma is highly heritable, even in pre-school children exposed to the same environmental allergens in the home.

"Shared environmental factors, such as rearing environment, family diet, and air pollutants seem to play a minor role."

The UK has one of the highest asthma rates in the world and more than 80% of asthmatics have their first episode before the age of five.

Parents of 4,910 four-year-old twins born in England and Wales between 1994 and 1995 were questioned for the survey.

They were asked about the treatment their children had been given for asthma.

Parents were also asked whether their children were identical twins, who share all their genes, or non-identical twins, who only share about half.

A higher rate of asthma among identical twins would indicate genetic factors at work.

The researchers, led by Dr Gesina Koeppen-Schomerus at the Institute of Psychiatry, King's College Hospital, found that identical twin pairs had far more similar asthma histories than non-identical pairs.