Smoking Attenuates Increase in Exhaled Nitric Oxide in Atopic but Not in Nonatopic Young Adults with Asthma

• Published in: International archives of allergy and immunology Vol. 152; no. 3; pp. 226 - 232
• Main Authors: Rouhos, Annamari, Ekroos, Heikki, Karjalainen, Jouko, Sarna, Seppo, Haahtela, Tari, Sovijärvi, Anssi R.A.
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland Karger 01.01.2010; S. Karger AG
• Subjects: Adolescent; Adult; Asthma; Asthma - complications; Asthma - immunology; Asthma - metabolism; Asthma - physiopathology; Biological and medical sciences; Breath Tests; Bronchial Hyperreactivity - physiopathology; Female; Forced Expiratory Volume - physiology; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Hypersensitivity, Immediate - complications; Hypersensitivity, Immediate - immunology; Hypersensitivity, Immediate - metabolism; Immunopathology; Male; Medical sciences; Nitric oxide; Nitric Oxide - metabolism; Original Paper; Sarcoidosis. Granulomatous diseases of unproved etiology. Connective tissue diseases. Elastic tissue diseases. Vasculitis; Skin Tests; Smoking; Smoking - metabolism; Spirometry; Tobacco, tobacco smoking; Toxicology; Vital Capacity - physiology; Young Adult; Young adults; Exhaled nitric oxide; Asthma; Smoking; Atopy; Human; Intrinsic asthma; Allergy; Lung disease; Immunopathology; Exhaled nitric oxide Smoking; Respiratory disease; Tobacco smoking; Expiration; Increase; Immunology; Nitric oxide; Young adult; Bronchus disease; Obstructive pulmonary disease; Respiration
• ISSN: 1018-2438; 1423-0097
• DOI: 10.1159/000283029

Background: Measurement of fractional exhaled nitric oxide (FENO) is useful in assessing eosinophilic airway inflammation. Smoking may modify airway inflammation and reduce FENO levels, compromising the diagnostic value of FENO in smokers. How smoking influences FENO in atopic versus nonatopic asthmatics is unknown. The aim of the present study was to compare FENO in atopic and nonatopic steroid-naive young asthmatic adults and in healthy subjects in terms of smoking. Methods: Forty-six (30 atopic) smoking and 70 (54 atopic) nonsmoking steroid-naive army conscripts (mean age 20 years) with current symptomatic asthma underwent FENO measurement, skin prick tests, spirometry with a bronchodilation test, bronchial histamine challenge, and a standardized exercise test. Ten healthy smokers and 9 healthy nonsmokers underwent FENO measurement, spirometry and bronchial histamine challenge. Results: Smokers with asthma showed significantly higher FENO than did healthy smokers and nonsmokers (p = 0.001, both comparisons). Among atopic asthmatics, FENO was lower in smokers than in nonsmokers (p = 0.002) whereas among nonatopic asthmatics no such difference was detectable (p = 0.89). However, even among nonatopic asthmatic smokers FENO was significantly higher than among healthy controls (p = 0.01). Conclusion: Smoking seems to attenuate the increase in FENO in atopic but not in nonatopic asthmatics. This finding suggests differences in biochemical mechanisms of NO formation in atopic and nonatopic asthma. However, FENO was significantly higher both in atopic and nonatopic asthmatic smokers than in healthy controls. This suggests that FENO can be applied for diagnostic purposes also in young adult smokers.