Depression, Asthma, and Bronchodilator Response in a Nationwide Study of US Adults

Background: Little is known about the relation between 2 common comorbidities (depression and anxiety) and asthma or bronchodilator response (BDR). Objective: To examine the association between depressive symptoms and asthma or BDR in US adults. Methods: Cross-sectional study of 20,272 adults aged 20 to 79 years from the 2007-2012 National Health and Nutrition Examination Survey. Depressive symptoms were measured using the 9-item Patient Health Questionnaire, and classified as none to minimal, mild, moderate, moderately severe, and severe. Major depression (comprising moderately severe to severe symptoms) was defined as a 9-item Patient Health Questionnaire score of 15 or more. Anxiety was defined as 5 or more days feeling anxious in the previous month. Current asthma was defined as having been diagnosed with asthma by a doctor or health professional and 1 or more asthma attack in the previous year. BDR (as percentage of baseline FEV₁) was measured in 1356 participants with FEV₁/forced vital capacity of less than 0.70 and/or FEV₁ less than 70% of predicted. Logistic or linear regression was used for the multivariable analysis. Results: Depressive symptoms were significantly and linearly associated with asthma, independently of anxiety symptoms. Subjects with major depression had 3.4 times higher odds of asthma than did those with minimal or no depressive symptoms (95% CI, 2.6-4.5; P <.01). Among adults with asthma, major depression was associated with a 4.2% reduction in BDR (95% CI, -7.5% to -0.8%; P =02). Major depression was not associated with BDR among adults without asthma. Anxiety was not associated with asthma or BDR. Conclusions: Depressive symptoms are associated with asthma in adults, independently of anxiety symptoms. Major depression is associated with reduced BDR in adults with asthma.