TABLE 1

Population characteristics

AllNo coughNonproductive coughProductive cough
Subjects n13 50011 3239171260
Age years52±752±752±752±7
Female53526056
BMI kg·m−226.0±4.525.9±4.426.0±4.726.9±5.2
Smoking status
 Never-smoker48495039
 Ex-smoker34353228
 Current smoker18161832
Hypertension22212727
Diabetes4.13.94.86.0
Stroke or ischaemic heart disease3.93.64.16.0
Ever-diagnosed asthma34285255
Wheeze in preceding 12 months19143062
Education level
 Elementary school11111016
 High school42423943
 College/university47475141
Currently working86878478
Ever changed job because of breathing problems1.81.33.15.2
Possible causes of cough
 Current asthma8.56.013.227.6
 COPD2.71.74.010.7
 Chronic rhinosinusitis7.15.28.223.5
 Gastro-oesophageal reflux7.56.410.015.2
 Any identifiable cause#21.116.829.053.6

Data are presented as mean±sd or %, unless otherwise stated. BMI: body mass index; COPD: chronic obstructive pulmonary disease. #: any of current asthma, COPD, chronic rhinosinusitis and/or gastro-oesophageal reflux.