The Relationship Between Obesity, Asthma Control, And Airway Inflammatory Phenotype

Objective To explore the characteristics of obesity-associated asthma and the relationship between obesity and asthma control, and airway inflammatory phenotype.Methods A cross-sectional study was designed to prospectively collect clinical data from 69 subjects with asthma. Asthma control level was assessed by Asthma Control Test (ACT) and GINA. Furthermore, height and weight were measured and body mass index (BMI) was calculated. Lung function and sputum induction were performed, and differential cell count was obtained from peripheral blood and induced sputum.Results The included subjects were divided into 2 groups as the normal group (n=54) and the obesity group (n=15). ACT level of asthma control (P=0.009) and GINA level of asthma control (i*=0.004) were significantly different between two groups. The number of neutrophils in induced sputum (P=0.022) and the number of lymphocytes in peripheral blood (P=0.008) was significantly different between two groups. BMI positively related to the number of neutrophils in induced sputum (r=0.31,P=0.049) and the number of lymphocytes in peripheral blood (r=0.33, P=0.008). Increased BMI deteriorated asthma control levels assessed by ACT (OR=1.81,95%CI=[1.00,3.26], P=0.050) and GINA (OR=2.39,95%CI=[1.29,4.43], P=0.006). Obesity indicated poor asthma control assessed by ACT (P=0.009) and GINA (P=0.008) after adjusting for age, sex, duration of asthma, FEV1%pre, smoking, and the number of neutrophils in peripheral blood.Conclusion In Chinese subjects with asthma, neutrophilic inflammatory phenotype in induced sputum would dominate in airway inflammation of obesity-associated asthma. Obesity is a risk factor that deteriorates asthma control level.