Abstract
BACKGROUND Chronic cough is a common respiratory symptom, and, if persistent, the patient's quality of life can worsen and result in a depressive mood, or vice versa. Although previous reports suggest a relationship between chronic cough and depression, we further investigated this relationship according to smoking status and lung function. METHODS This observational study used cross-sectional data from the 6th Korean National Health and Nutrition Examination Survey (2014 and 2016). Propensity score matching using age, sex, smoking status, and lung function was performed for participants with and without chronic cough to reduce the confounding effects associated with depressive mood. Questionnaires recorded coughs persisting for >3 months and the Patient Health Questionnaire-9 (PHQ-9) assessed the severity of depressive mood. RESULTS Among 12 494 participants who were >18 years old, 226 with chronic cough were matched with 226 with non-chronic cough. Overall, chronic cough participants showed higher PHQ-9 scores than the non-chronic cough participants (4.29 ± 5.23 vs. 2.63 ± 3.38, P < .001). When stratified by sex, the difference remained significant in women (5.69 ± 5.96 vs. 3.05 ± 3.97, P < .001) but not in men (3.18 ± 4.27 vs. 2.31 ± 3.65, P = .092). When stratified by lung function status, the difference remained significant for those with normal lung function (4.32 ± 5.32 vs. 2.78 ± 3.86, P = .003) and reduced lung function (4.19 ± 4.93 vs. 2.11 ± 3.55, P ≤ 0.001). Multivariate logistic regression analysis revealed that chronic cough was associated with PHQ-9 score (odds ratio [OR], 1.06; 95% confidence interval [CI], 1.014-1.27, P = .014), chronic obstructive pulmonary disease (OR, 4.87; 95% CI, 1.041-22.86, P = .044) and physician-diagnosed bronchial asthma (OR, 2.93; 95% CI, 1.162-7.435, P = .023). CONCLUSIONS Depressive mood is significantly correlated with chronic cough in females.
