Impact of mental health and personality traits on the incidence of chronic cough in the Canadian Longitudinal Study on Aging

Background: Chronic cough is a common troublesome condition, but risk factors for developing chronic cough are poorly understood. The aim of this study was to understand the relationship between mental health disorders, personality traits and chronic cough. Methods: The Canadian Longitudinal Study on Aging is a prospective, nationally generalisable, random sample of adults aged 45-85 years at baseline recruited between 2011 and 2015, and followed-up 3 years later. Chronic cough was defined as a daily cough over the last 12 months. Incident chronic cough was defined as those participants who reported new-onset chronic cough between baseline and follow-up 1. Current depressive symptoms and psychological distress were assessed using the Center for Epidemiologic Study Short Depression Scale (CESD-10) and Kessler Psychological Distress Scale (K-10), respectively. The "Big Five" personality traits were assessed using the Ten-Item Personality Inventory. Relative risks are reported using a multivariate mutually adjusted model. Results: At follow-up 1, 2506 participants (11.1%) reported new-onset chronic cough during the ∼3-year interval. Depressive symptoms (CESD-10 ≥10: relative risk 1.22 (95% CI 1.03-1.44)) and psychological distress (K-10 ≥22: relative risk 1.20 (95% CI 1.07-1.36)) at baseline were both independent predictors of a higher risk of incident chronic cough. Prevalent and incident chronic cough were also independently associated with an increased risk of developing depressive symptoms and psychological distress. Personality traits did not influence the development of chronic cough but did increase the risk of depressive symptoms and psychological distress. Conclusions: This study shows that there is a bidirectional relationship between chronic cough, and depressive symptoms and psychological distress, and personality traits do not independently influence the development of chronic cough.