Obese or overweight children with asthma could be using inhaled corticosteroids (ICS) to no avail, combined results from observational studies suggest.
Using Mendelian randomization, a method for reducing bias in observational studies, investigators from the University of Amsterdam Medical Center performed an analysis of data from four cross-sectional studies and one cohort study on a total of 1,511 children with asthma.
Dr Cristina Longo
They showed that every 1-unit increase in the body mass index (BMI) z score was associated with a more than twofold higher odds ratio for exacerbation, reported Cristina Longo, PhD, a former postdoctoral fellow at AMC, and assistant professor of medicine at the University of Montreal.
"In this large, multicenter Mendelian randomization study, our findings support current evidence that children with higher BMI status respond inadequately to inhaled corticosteroids, and that this association is likely not explained by measured confounding or reverse causation," she said in an oral abstract presentation during the European Respiratory Society International Congress.
Unmeasured Confounding
The obese-asthma phenotype in children is characterized by reduced lung function, high symptom expression, poor response to ICS, and high health care utilization.
"While most observational studies suggest that weight status is associated with asthma exacerbations, despite using inhaled corticosteroids, it's unclear whether these associations may be due to unmeasured confounding or reverse causation, which captures the idea that perhaps obesity is a consequence rather than a cause of uncontrolled severe asthma," she said.
