Table 1 Items and response categories from the questionnaire
Do you smoke? | • Yes, daily • Yes, at least once a week • Yes, occasionally (part-time smoker) • No, I quit in (year) • No, I have never smoked |
On average, how much do you smoke daily? | • Number of cigarettes • Number of cheroots • Number of cigars • Number of pipes |
During the past 4 weeks, how much of the time were you troubled by dyspnea, wheezing or coughing? (only one x) | • All of the time • Most of the time • Now and then • Rarely • Not at all |