[Studies on airway hyperresponsiveness by the Astograph(r) method in asthmatics and young adult non-asthmatic asymptomatics].
We investigated airway hyperresponsiveness (AHR) by the continuous inhalation method using an Astograph(R) in 105 asthmatics and 141 non-asthmatic asymptomatics. The range of Dmin (1 U=one minute inhalation of 1 mg/ml of methacholine) of asthmatics was 0.001 to 28.70 U, and that of adjusted Dmin of non-asthmatic asymptomatics was 0.28 to 190 U; thus, an apparent overlap was recognized in the distributions of Dmin. Ninety-five percent of asthmatics had a Dmin lower than 7 U, and 95% of non-asthmatic asymptomatics had a Dmin higher than 0.9 U. Presuming that almost all asthmatics had AHR, it was inferred that nearly half of non-asthmatic asymptomatics had AHR, too. Comparison with previous reports suggests that AHR in healthy people may be increasing generally. When Dmin is determined to be>7 U by the Astograph(R) method, it is likely that the patient does not have asthma. When a patient has a Dmin<0.9 U, it is highly probable that the patient has asthma.
Fukui
Yoshinobu
Y
First Department of Medicine, Hokkaido University School of Medicine, Hokkaido, Japan. yo-fukui@med.hokudai.ac.jp
Yamaguchi
Etsuro
E
Hizawa
Nobuyuki
N
Maeda
Yukiko
Y
Takahashi
Daisuke
D
Konno
Satoshi
S
Kobayashi
Motoko
M
Hosokawa
Takeshi
T
Jinushi
Eisei
E
Takamura
Kei
K
Nasuhara
Yasuyuki
Y
Nishimura
Masaharu
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001249:Asthma / Q000503:physiopathology*; D016535:Bronchial Hyperreactivity / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D008875:Middle Aged
D016210:Methacholine Chloride