Defining the risk factors for acute, subacute and chronic cough: a cross-sectional study in a Finnish adult employee population

Objectives Chronic cough is linked to various long-standing risk factors like asthma, chronic rhinitis and oesophageal reflux disease. On the contrary, acute and subacute cough are usually considered to be caused by acute respiratory infections. Little is known about the possible long-standing risk factors for acute and subacute cough. In this study, we have identified the long-standing risk factors for acute, subacute and chronic cough in order to identify the risk factors specifically associated with chronic cough. Design A comprehensive 80-item questionnaire was sent via email to the participants. Setting A community-based study to all public service employees of two towns in central Finland. Participants There were 13 980 employees, of them 3697 responded (26.4%). Among the responders, there were 199 subjects with current daily acute cough (duration <3 weeks, prevalence 5.4%), 126 subjects with current daily subacute cough (duration 3-8 weeks, prevalence 3.4%) and 267 subjects with current daily chronic cough (duration >8 weeks, prevalence 7.2%). Primary outcome measures The risk factors that associated with each cough subtype. The subjects without any cough formed the reference group. Results Several risk factors were associated with both short and long cough subtypes namely family history of chronic cough, moisture damage exposure and number of reported somatic symptoms. Furthermore, allergy was associated with acute and subacute cough. Current asthma and chronic rhinitis were associated with subacute and chronic cough. Oesophageal reflux disease and advanced age were associated with chronic cough. Conclusions The specific risk factors for chronic cough were oesophageal reflux disease and advanced age. Acute and subacute cough should not be regarded merely as symptoms of acute respiratory infections but possible manifestations of long-standing risk factors. A new risk factor for all cough types was family history of chronic cough.