TABLE 2

Inclusion and exclusion criteria

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.