Criteria | Cases | Controls |
Inclusion | Symptoms of asthma and/or use of asthma medication in the past 12 months | No previous or current history of asthma |
Exclusion | Chronic disease apart from asthma# Pregnancy | Chronic disease# Pregnancy |
Postpone appointment | Acute exacerbation of asthma Symptomatic respiratory infection in the last 4 weeks | Symptomatic respiratory infection in the last 4 weeks |
#: people with the following chronic diseases should be excluded: chronic obstructive pulmonary disease, bronchiectasis, cystic fibrosis, any form of heart disease (including hypertension/high blood pressure, congenital heart disease or if taking heart medication), any other chronic lung or chest problems, tuberculosis, HIV.