Obesity

Obesity affects 650 million people globally, and approximately one-third of people with severe asthma. Obesity is both a major risk factor and a disease modifier of asthma. As a cofactor, obesity drives one-quarter of hospital asthma admissions, which is more than smoking, gastro-oesophageal reflux disease, rhinosinusitis, anxiety and depression combined. Obesity, like asthma, is a major contributor to health inequalities. Maternal obesity increases asthma risk in children by 15–30%. Obesity is also associated with late-onset asthma. Obesity may drive asthma via several mechanisms: physical restriction of lung function, induction of AHR, systemic IL-6-mediated inflammation, IL-5-dependent mucosal eosinophilia, and effects on inflammasomes, surfactant proteins and steroid responsiveness. Currently, we have little to offer people with obesity-related asthma. Lifestyle interventions have limited efficacy and very few people receive surgery. The outlook for these patients may be transformed by the advent of highly effective glucagon-like peptide-1 receptor agonists, which are likely to make obesity-related asthma the most important treatable trait after type 2 inflammation.