Fig. 2.

Prevalence of doctor diagnosed asthma and wheezing symptoms stratified by age (prevalence per 1000 and 95% confidence intervals). The prevalence of BA was calculated per 1000 persons and expressed with 95% confidence intervals in three age groups: 18–39, 40–64, and ≥ 65 years old, for doctor diagnosed asthma: when self-reported by the respondent (the respondent reported that he/she had ever been diagnosed with BA by a doctor while completing the study questionnaire), and wheezing symptoms: when the respondent reported wheezing at the ATS Respiratory Symptoms Questionnaire (answered positive to the question: “Does your chest ever sound wheezy or whistling?”)