Prevalence of respiratory symptoms in the city of Oslo.

In the first phase of a two-phase cross-sectional survey conducted in Oslo from 1972 to 1974 a questionnaire was mailed to a random sample of 19998 persons aged 15 to 70 years. Information was received from 88.7% of those alive in the sample. The completion rate for each of 11 questions on respiratory symptoms in the mail questionaire varied between 94 and 98%. The crude prevalence rates of the symptoms cough in the morning, breathlessness climbing two flights of stairs and wheezing were 24%, 11% and 17%. Only 27% of the men and 46% of the women in the survey population were non-smokers. Among non-smokers, phlegm was reported more fequently by men, irrespectively of age, whereas breathlessness was reported more often by women than by men. In both sexes of non-smokers, a linear increase in prevalence of symptoms with age was observed for breathlessness, attacks of breathlessness, and coughing in the morning and during the day. The prevalence of respiratory symptoms was closely related to the amount smoked.