Table 1

Chronic bronchitis and bronchitis-like symptom definitions

Baseline (2006–2013)
Prevalent outcomes Assessment item
Chronic bronchitisCough up phlegm in winter when getting up, during daytime or at night almost daily for at least 3 months a year
Usual sputumUsually cough up phlegm in winter when getting up, during daytime or at night
Chronic coughCough in winter when getting up, during daytime or at night almost daily for at least 3 months a year
Usual coughUsually cough in winter when getting up, during daytime or at night
Follow up (2014–2017)
Incident outcomes Assessment item
Chronic bronchitisCough up mucus every day for a period of 3 months a year
Chronic coughCough almost every day for a period of 3 months a year