A new study concludes that the risk is higher among those who have non-allergic asthma, have had the disease for longer or are on corticosteroids

Adults with asthma at increased risk of developing obesity

photo_camera Shutterstock/ Mladen Zivkovic. - This is the first study to show this association in adults.

A study of more than 8,700 participants from 11 European countries and Australia has concluded that adults with asthma are more likely to become obese in the future. The research, led by the Barcelona Institute for Global Health (ISGlobal), a centre supported by the "la Caixa" Foundation, has also shown that the risk is higher among patients with non-allergic asthma, with a longer period of illness or on treatment with corticosteroids. These results have been published in Thorax.

"Several studies have shown that asthma and obesity share some socioeconomic, behavioural and environmental risk factors that may lead to the development of both diseases. Some previous research has focused on the mechanisms by which obesity may lead to asthma, but the reverse relationship has not received much attention until recently," says Subhabrata Moitra, who conducted this research at ISGlobal and is now a researcher at the University of Alberta.

The team used data from the European Community Respiratory Health Survey (ECRHS) cohort study, collected in three waves between 1990 and 2014 and with follow-up visits at approximately 10-year intervals. The different waves collected data from questionnaires, lung function tests and measurements taken to determine participants' body mass index and asthma status and characteristics.

la caixa

Between the first and second follow-up, 14.6% of non-asthmatic participants developed obesity, while the percentage increased to 16.9% among asthmatic participants. The difference between the two groups became more apparent when the research team translated it into a relative risk that took into account the role of other factors, such as asthma and smoking, and found that asthmatics had a 21% higher risk of obesity compared to non-asthmatics.

People with longer duration of asthma had a 32% higher risk of obesity than those with shorter duration of disease, and those with non-allergic asthma had a 47% higher risk than those with allergic asthma. Participants who treated respiratory disease with corticosteroids had a 99% higher risk of obesity compared to those who did not use this treatment, which has been associated with abnormal weight gain in previous research.

"One possible explanation for asthma-associated weight gain could be reduced physical activity in asthma patients. However, our results do not support this hypothesis, as the levels of physical activity in our study did not affect the observed association", says Judith García-Aymerich, head of the Noncommunicable Diseases and Environment Programme at ISGlobal and lead author of the study. "Regardless of the mechanisms, which remain unknown, our results have implications for the clinical care of adults with asthma", she adds.

Unlike a previous study that found this association between asthma and weight gain only in women, in this case there was no sex difference. Another previous study had found an association between asthma in children and obesity after a 10-year follow-up, but this is the first known study to show a similar association in adults, regardless of gender.

The study was conducted in Australia, Belgium, Estonia, France, Germany, Iceland, Italy, Norway, Spain, Sweden, Switzerland, United Kingdom and United States.

REFERENCE:

Moitra S, Carsin A-E, Abramson MJ, et al. Thorax. Epub ahead of print: 28 April, 2022. https://doi.org/10.1136/thoraxjnl-2021-217867

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