The study will be carried out in collaboration between respiratory physicians, clinical physiologists, physiotherapists, speech- and language therapists and gastroenterologists.~The primary hypothesis of the planned study is:~The cough suppressive therapy improves chronic cough-related quality of life and work ability, and is sustained over six months after treatment.~The secondary hypotheses of the planned study are:~Treatment of chronic cough by the cough suppressive therapy can reduce cough frequency (measured by an automated cough detector), airway inflammation and airway resistance.~Baseline differences in clinical findings, biomarkers and physiologic measurements predict different treatment effects.~The following data will be collected before and after treatment:~Standardized questionnaires for diagnosis of background factors and cough duration, LCQ, WAI, questions on sick leave days, voice disturbance questionnaire.~Physiological measurements: Spirometry with reversibility test, impulse oscillometry before and after provocation with hypertonic saline inhalation. 24 hours cough frequency analysis, voice analysis.~Biomarkers: Fractional exhaled nitric oxide (FeNO), blood-eosinophils and eosinophil cationic protein in serum, proteomics in particles in exhaled air (PExA)
In this randomized, placebo-controlled, interventional study on chronic cough a non-pharmacological cough suppressive therapy is the intervention to be studied, with a control group receiving treatment consisting of general healthy lifestyle advice. The following data will be collected before, after and up to six months after treatment: Standardized questionnaires for diagnosis of background factors, Leicester Cough Questionnaire (LCQ), Work Ability Index (WAI), and cough frequency as well as lung function and biomarkers.~The primary treatment effect measurement will be changes in chronic cough-related quality of life, measured by the Leicester Cough Questionnaire (LCQ).