Passive and active smoking and exhaled nitric oxide levels according to asthma and atopy in adults.
BACKGROUND
No data are available regarding the utility of fractional exhaled nitric oxide (FeNO) level in guiding therapy in smoking asthmatic patients. Identification of the effect of smoking in a large sample is needed.


OBJECTIVE
To study the association between smoking and FeNO level according to current asthma and atopy status in adults from the French EGEA (Epidemiological study on the Genetics and Environment of Asthma, bronchial hyperresponsiveness and atopy).


METHODS
Levels of FeNO were measured at 50 mL/s in 654 adults (268 asthmatic participants). Active smoking and environmental tobacco smoke (ETS) exposure at home, at work, and during leisure activities were recorded. Participants were categorized as having no exposure to ETS, mild exposure (ETS <2 h/d), and noticeable exposure (ETS > or = 2 h/d). Multivariate analyses were performed, with adjustment for age, sex, height, and center.


RESULTS
Mean adjusted FeNO values increased with asthma (15.1 vs 19.5 ppb), atopy (14.2 vs 18.9 ppb), and eosinophilia (15.8 vs 24.8 ppb) (P < .001 for all). Mean FeNO levels decreased with smoking (18.4, 17.5, and 14.5 ppb in nonsmokers, ex-smokers, and current smokers, respectively; P for trend = .001). The association with smoking was observed in nonasthmatic and asthmatic participants, especially in atopic asthmatic participants. Multivariate analyses showed that ETS exposure of at least 2 h/d and active smoking were negatively and significantly associated with FeNO levels independent of age, sex, height, and center in nonasthmatic participants (mean [SE], -0.13 [0.06], P = .03 and -0.10 [0.03], P < .001) and in asthmatic participants (mean [SE], -0.18 [0.07], P = .01 and -0.14 [0.04], P = .02).


CONCLUSIONS
Active and passive smoking decreased FeNO levels in adults. Careful consideration of asthma, atopy, and active and passive smoking are needed to interpret FeNO values.
Nadif
Rachel
R
Inserm, CESP Centre for Research in Epidemiology and Population Health, Respiratory and Environmental Epidemiology Team U1018, Villejuif, France. rachel.nadif@inserm.fr
Matran
Regis
R
Maccario
Jean
J
Bechet
Magali
M
Le Moual
Nicole
N
Scheinmann
Pierre
P
Bousquet
Jean
J
Kauffmann
Francine
F
Pin
Isabelle
I
D000328:Adult; D001249:Asthma / Q000175:diagnosis / Q000453:epidemiology* / Q000378:metabolism; D001944:Breath Tests / Q000379:methods; D003876:Dermatitis, Atopic / Q000175:diagnosis / Q000453:epidemiology* / Q000378:metabolism; D004802:Eosinophilia / Q000453:epidemiology / Q000378:metabolism; D045853:Exhalation; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000032:analysis / Q000378:metabolism*; D012680:Sensitivity and Specificity; D012907:Smoking / Q000378:metabolism*; D014028:Tobacco Smoke Pollution
D014028:Tobacco Smoke Pollution; D009569:Nitric Oxide