Table 3

Risk factors for chronic cough, chronic expectoration and chronic bronchitis#

ReferenceOdds ratio95% Confidence intervalp-value
Chronic cough
 Current smokersNonsmokers2.792.30–3.39<0.0001
 ComorbidityNo comorb2.942.47–3.50<0.0001
 Pack-yrs11.011.01–1.02<0.0001
Chronic expectoration
 Current smokersNonsmokers1.641.24–2.16<0.0001
 ComorbidityNo comorb2.742.19–3.42<0.0001
Chronic bronchitis
 Current smokersNonsmokers3.412.75–4.22<0.0001
 ComorbidityNo comorb4.904.10–5.86<0.0001
 Pack-yrs11.021.01–1.02<0.0001
  • #: calculated by multivariate logistic regression analysis and adjusted for age and sex