Background and aim: In an inception cohort study of 457
asthmatic children diagnosed at the age of 3 to 4 years, airway
hyperresponsiveness (AHR) was assessed 6 years after first diagnosis in
a subgroup of 84 children. Our objective was to associate the level of
AHR with the symptomatic asthma status at follow-up.
Methods: Information on respiratory symptoms and medication
use for the previous 6 years was obtained. Children with reported
wheezing episodes during the previous year (n = 169) or for ≥ 2
years at any time during the follow-up period (n = 85) were eligible
for the challenge test.
Results: Among the 254
eligible children, 166 were randomly selected. The parents of 88 of
them consented to have their child participate. At the time of
assessment of AHR, 19 children (22%) were asymptomatic and 24 others
(29%) had symptoms but did not use any medication. Forty-one children
(49%) were symptomatic and required medication, including
antiinflammatory preparations in 26 instances (31%). All but two
children had significant AHR. There was no significant association
between the level of AHR and graded symptomatic and medication score.
Twenty-four of the 70 children (34%) with greatly enhanced AHR used no
Conclusions: This study shows that (1)
almost all children first diagnosed with asthma 6 years ago and with
persisting but not necessarily current symptoms of asthma have
increased AHR, which satisfies a proposed epidemiologic definition of
asthma; (2) AHR was present in 95% of the 20 currently asymptomatic
children; and (3) one third of children with greatly enhanced AHR did
not use any treatment.