Prevalence of childhood asthma: facts, tendencies and interpretations

Questionnaire surveys are an appropriate instrument to assess epidemiologic data on respiratory ill health, to analyse influences of environmental factors on respiratory morbidity and to evaluate treatment strategies. To investigate the prevalence rates of asthma and symptoms suggestive of asthma we performed population surveys in Swiss school children. Special attention is drawn to particular aspects such as atypical symptoms, underdiagnosis and undertreatment of asthma.