Asthma-obesity genetic link
05 January 2006

The link between asthma and obesity may be down to shared genetic factors that cause both conditions, according to a new piece of research.

Existing studies have shown that there is a strong correlation between asthma and a high body mass index (BMI), and scientists have tried to discover whether one condition is more likely to lead to the other, or vice versa.

This latest study shows that in fact the relationship between the two may be genetic – that a common set of genes may predispose people both to have asthma and to be obese.

Scientists at the University of Washington in Seattle reached their conclusions by studying 1,001 identical and 383 non-identical same-sex pairs of twins. In this way they could assess the genetic influences on asthma and obesity, as well as environmental factors.

The researchers recorded the participants' BMI and the incidence of asthma. For the study, 'obesity' was defined as a BMI of 30 kg/sq.m or more.

They found a significant association between asthma and obesity in the group, and after analysing the data estimated that 8% of the genetic components of both conditions were shared.

Lead researcher Dr Teal Hallstrand concluded: 'The covariation between obesity and asthma is predominantly caused by shared genetic risk factors for both conditions.'

The researchers also suggested that genetics may determine how far different environmental factors influence the development of asthma and obesity.

The study was published in the Journal of Allergy and Clinical Immunology.