Obesity and Asthma: Endotypes and Mechanisms

Obesity has as bi-directional relationship with asthma. While obesity confers a dose-dependent risk of developing asthma, asthma increases the risk of obesity, from oral corticosteroid exposure or activity limitation for example. Poorer outcomes including increased risks of exacerbations and disease progression have made obesity a high priority research area in asthma. Alongside challenges such as differential treatment responses, obesity-related asthma research has been challenging due to the complex and heterogeneous inflammatory milieu noted in this population. For example, further research is needed to deconstruct the metabolic mechanisms, altered innate and adaptive immune responses and even the performance of clinically available biomarkers in obese asthma patient. Efforts to understand phenotypes and endotypes via cluster analyses in subpopulations such as severe asthma has shed some light on the pathophysiologic mechanisms of obese asthma, but much remains unknown. In this chapter, we review our current knowledge of the pathophysiologic mechanisms, phenotypes–endotypes and clinical challenges pertaining to the obese asthma patient in a manner of elucidating their unique challenges.