Airway responsiveness to acetaldehyde in patients with asthma: relationship to methacholine responsiveness and peak expiratory flow variation.
BACKGROUND
Although airway hyperresponsiveness to inhaled acetaldehyde has been documented in Japanese patients with asthma, the response to this bronchoconstrictor agent has never been studied in Caucasians.


OBJECTIVE
The objectives of the study were to determine differences in airway responsiveness to acetaldehyde between asthmatic and healthy subjects, and to examine the relationship between acetaldehyde responsiveness and the variability of peak expiratory flow (PEF).


METHODS
The response to methacholine and acetaldehyde challenges was measured in 81 non-smoking adults (61 asthmatics and 20 normal controls). Subjects recorded PEF morning and evening for 14 days. The response to both bronchoconstrictor agents was measured by the PC20 (provocative concentration required to produce a 20% fall in FEV1). PEF variation was expressed as amplitude percentage mean, and as low percentage best (lowest PEF expressed as a percentage of the best PEF recorded).


RESULTS
The two types of challenge yielded a similarly high level of sensitivity (100% for methacholine and 92% for acetaldehyde) and specificity (90 and 100%, respectively) to distinguish between asthma and controls. Asthmatic subjects were on average 265-fold less sensitive to acetaldehyde than to methacholine. PC20 acetaldehyde correlated weakly but significantly with both indices of PEF variation (amplitude percentage mean: rho = - 0.36, P = 0. 004; low percentage best: rho = 0.42, P = 0.001).


CONCLUSIONS
These results indicate that airway hyperresponsiveness to acetaldehyde is a sensitive and specific indicator for separating asthmatic and normal subjects. Airway responsiveness to methacholine or acetaldehyde and PEF variation are not reflecting the same pathophysiological process in the airways.
Prieto
L
L
Sección de Alergología, Valencia, Spain.
Sánchez-Toril
F
F
Brotons
B
B
Soriano
S
S
Casañ
R
R
Belenguer
J L
JL
D000079:Acetaldehyde; D000328:Adult; D000403:Airway Resistance / Q000187:drug effects; D001249:Asthma / Q000175:diagnosis / Q000503:physiopathology*; D016535:Bronchial Hyperreactivity / Q000139:chemically induced / Q000503:physiopathology*; D001985:Bronchial Provocation Tests; D016085:Bronchoconstrictor Agents; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D010366:Peak Expiratory Flow Rate / Q000187:drug effects; D016037:Single-Blind Method
D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride; D000079:Acetaldehyde