title: Airway responses to methacholine in asymptomatic nonatopic cigarette smokers.
abstract: We prospectively performed methacholine bronchoprovocation challenges on 46 young smokers to examine the effects of cigarette smoking on airway responsiveness. The subjects, ages 18-35 yr, had no past or present history or physical examination findings of asthma or other lung diseases, rhinitis, allergic diseases, or respiratory infections; were skin test negative to 29 common aeroallergens; and had base-line pulmonary function values greater than 80% predicted. Sixteen of 46 (35%) subjects had a 20% or greater drop in forced expiratory volume in 1 s at a provocative methacholine concentration less than or equal to 25 mg/ml. The degree of methacholine responsiveness was not dependent upon base-line pulmonary function values or the amount of cigarettes consumed, and there was no association between the amount of cigarettes consumed and base-line pulmonary function values. These data suggest that many young asymptomatic nonatopic smokers have increased airway responsiveness to inhaled methacholine without clinically significant hyperreactive airway disease.
authors.forename: T B
authors.initials: TB
authors.lastname: Casale
authors.forename: B J
authors.initials: BJ
authors.lastname: Rhodes
authors.forename: A L
authors.initials: AL
authors.lastname: Donnelly
authors.forename: J M
authors.initials: JM
authors.lastname: Weiler
mesh_terms: D000293:Adolescent; D000328:Adult; D000403:Airway Resistance / Q000187:drug effects*; D001980:Bronchi / Q000187:drug effects / Q000502:physiology; D001985:Bronchial Provocation Tests; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D008688:Methacholine Compounds / Q000494:pharmacology*; D012907:Smoking; D014797:Vital Capacity
chemical_list: D008688:Methacholine Compounds; D016210:Methacholine Chloride