Overlap phenotypes of asthma in adults: Obesity and atopy

Background: Although plenty of evidence suggests that atopy doesn9t mediate the relationship between obesity and asthma, asthmatic patients with overlap phenotypes of obesity and atopy are facing more complex problems. Uncertain relationship between obesity and atopy may result in different clinical features and airway or systemic inflammatory status.Methods: A cross-sectional study was conducted in 74 adult subjects with stable asthma. Clinical characteristics were collected and skin prick test, lung function test, sputum induction, and blood count were performed. The included subjects were classified into 4 groups: overlap group (n=11), obesity group (n=10), atopy group (n=30), nonallergic and normal weight asthma group (n=23). Factorial design ANOVA was used to analyze the interaction between atopy and obesity.Results: It found that overlap group had a highest proportion of depression symptoms (p=0.039); atopy contributed significantly to the age at onset of asthma symptoms (p=0.014); both obesity and atopy had effects on the percentage of neutrophils in peripheral blood (p=0.006 and p=0.028 respectively), while in induced sputum, interaction between obesity and atopy contributed to different proportion of neutrophils and macrophages(p=0.077 and p=0.047). Conclusions: Interaction between obesity and atopy can9t be ignored in clinical practice.