Study objective: We evaluated whether aging may produce
changes in bronchial hyperresponsiveness, risk of enhanced
bronchoconstriction, and changes of bronchoconstriction perception.
Setting: Each subject underwent a methacholine
bronchial challenge. Methacholine challenge was stopped when one of the
following conditions occurred: (1) plateau of bronchoconstriction; (2)
decrease of FEV1 > 40%; (3) FEV1 drop
below 1 L; or (4) excessive respiratory discomfort. Methacholine
dose-response curves were plotted both for FVC and FEV1.
The provocative dose of methacholine causing a 20% decrease in
FEV1 with respect to baseline (PD20) and the
fall in FVC (ΔFVC) at PD20 were computed. The Borg scale
was used for scoring the perception of respiratory
Patients: We compared 17 young
asthmatic patients (aged 22 to 45 years) with 17 older asthmatic
patients (aged 63 to 78 years) selected on the basis of similar
baseline pulmonary function and disease duration.
Results: No significant between-group difference was found
in PD20 and in plateau development. Conversely, ΔFVC was
significantly higher in the older group (mean ± SD, 15.5 ± 3.9%
vs 11.6 ± 5.5% in younger patients). In addition, ΔFVC
showed a positive linear relationship with age (p = 0.0026). Elderly
subjects were less aware of bronchoconstriction during the methacholine
challenge (p = 0.04).
Conclusions: In elderly
patients with asthma having comparable pulmonary function and disease
duration, bronchial responsiveness is not different from that observed
in younger asthmatic patients. Nevertheless, in such patients, an
age-related tendency to an enhanced bronchoconstriction and a reduced
perception of the degree of bronchoconstriction