Table 1– Selection criteria
Fulfilled the definition of current asthma, similar to that used in a recent publication 19
 Reported ever having asthma confirmed by a doctor 20
 And one or more of the following:
  At least one attack of asthma in the past 12 months
  Currently taking medicines for asthma
  At least one of the following respiratory symptoms in the past 12 months:
   Wheezing
   Nocturnal tightness in the chest
   Attack of shortness of breath when at rest during the day
   Attack of shortness of breath following strenuous activity
   Being awoken by an attack of shortness of breath
Onset of asthma >2 yrs before participating in the ECRHS II survey (i.e. current age minus age at onset >2 yrs); this criterion was intended to clarify it was exacerbation of asthma, and not onset of asthma, that was being studied
Worked during the past 12 months
Completed questionnaire items used to define exacerbation of asthma
  • ECRHS II: European Community Respiratory Health Survey, phase II (follow-up).