Table 2

Definition of respiratory symptoms

Symptoms	Definition
Cough		Answered yes to:
		Do you usually cough first thing in the morning in the winter?
		or
		Do you usually cough during the day, or at night, in the winter?
Sputum production		Answered yes to:
		Do you usually bring up any phlegm from your chest first thing in the morning in the winter?
		or
		Do you usually bring up any phlegm from your chest during the day or at night in the winter?
Cough and sputum production	Both cough and sputum production as defined above
Chronic bronchitis		Both cough and sputum production and answered yes to:
		Do you cough like this on most days for as much as 3 months each year?
		and
		Do you bring up phlegm like this on most days for as much as 3 months each year?