Over the last two decades, asthma and obesity have reached epidemic proportions. Obesity is a common comorbidity to asthma and it is commonly thought that obesity precedes the asthma symptoms. Now, the question has been raised about whether it is the other way around. Does obesity follow on the heels of asthma or is it asthma that raises the likelihood of becoming overweight?
Understanding this relationship could help doctors better give their professional recommendations in obese versus non-obese asthmatic patients.For instance, not automatically stepping up controller medication in overweight patients who report needing to use rescue medication often. Additionally, it may be that obese patients may be able to step down their level of controller medication, especially if the symptoms can be better dealt with through non-asthma related interventions.
In a recent study, aged 10-17 years children – both a higher and lower body mass index (BMI) – with a physician’s diagnosis of persistent asthma were monitored to assess asthma control, symptoms, and quality of life. The patients underwent methacholine challenge testing – a test to evaluate lung function and reactivity. Additionally, the patients experienced measurement of exhaled nitric oxide values – a test done to help evaluate whether their asthma (and inflammation) is under control.
Intriguingly, overweight children were less responsive to the methacholine challenge test, needing nearly four times the dose of methacholine before the lungs were responsive. Overweight children also had lower nitric oxide values, meaning inflammation in the lungs were still a problem.
However, there were no differences in regard to reported wheeze, chest tightness, or nocturnal symptoms between overweight and lean children. These findings are a distinction from previous research, which has mostly focused wheeze as a symptom most commonly associated with just obese children.
This study’s findings support exploring non-asthma related interventions before raising levels of controller medications in overweight asthma patients. These results also support the plan that overweight asthmatic patients may need different treatment plans to control their asthma appropriately.
Whether it is the reduced lung capacity and activity level due to asthma that causes obesity, or excess weight that induces the development of asthma, it is clear that these two issues have a linked relationship. However, further research into differences in obese patients with asthma will be needed to best assess optimal therapy and prevention.