Genes link asthma and body mass

Wednesday July 2nd, 2014

New findings show a genetic link between a child being overweight and risk of suffering from asthma, researchers say today.

Asthma rates have been rising over the past few decades, but the causes are unknown. Obesity may be a risk, so the team looked at the link using genetic information and information on asthma in 4,835 children.

A range of genetic differences were examined, as well as body mass index (BMI) and asthma. This showed that genetics were "strongly associated" with BMI and asthma. The risk of asthma appeared to be raised by 55% for every extra BMI point.

This effect appeared stronger for non-atopic asthma, which has no obvious trigger, than for atopic asthma, which is triggered by allergens and irritants such as dust mites and mould.

The researchers, led by Dr Raquel Granell of the University of Bristol, UK, say that the recent increase in asthma could be due to children's BMI rising.

"Higher BMI in mid-childhood could help explain some of the increase in asthma risk toward the end of the 20th century," they write in the journal PLoS Medicine today (2 July).

But they add: "The continued rise in obesity but with a slowing in the rise in asthma prevalence in some countries implies that other non-BMI-related factors are also likely to be important."

Overall, they conclude that efforts to cut obesity "may also help to limit the global rise in asthma". It is still unclear how extra body mass could trigger asthma. Several factors may be at play, including decreased lung function due to a build-up of fat, or the pro-inflammatory nature of adipose (fat) tissue.

Granell, R. et al. Effects of BMI, Fat Mass, and Lean Mass on Asthma in Childhood: A Mendelian Randomization Study. PLoS Medicine doi:10.1371/journal.pmed.1001669 [abstract]

Tags: Allergies & Asthma | Child Health | Genetics | Respiratory | UK News

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