[Bronchial hyperreactivity and epidemiology of bronchial asthma in childhood].

Respiratory symptoms are common in childhood with as many as 25% of children aged 7-10 years being troubled by recurrent episodes of cough and wheeze. Subjects with and without asthma differ both in the ease with which airway narrowing is produced by inhalation of nonallergic or nonsensitizing stimuli. A few epidemiologic studies are concerned with the prevalence of bronchial hyperresponsiveness in unselected children. Although increased airway responsiveness is predominantly reported in atopic individuals, even children with no history of atopy or symptoms suggesting asthma produce a bronchial obstruction being challenged by physical exercise, inhalation of cold air or distilled water and pharmacologic stimuli. The relationship between responsiveness to different challenges was investigated in 2 large epidemiological studies on school aged children. The following reports are an informative survey on acceptance, sensitivity, specificity and predictive value of epidemiologic instruments estimating bronchial responsiveness.