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J Allergy Clin Immunol. 2005 Jul;116(1):88-93.

Short and long-term effects of cigarette smoking independently influence exhaled nitric oxide concentration in asthma.

Author information

1
Department of Immunology, Division of Immunology, Infection and Inflammation, University of Glasgow, United Kingdom. cms4q@clinmed.gla.ac.uk

Abstract

BACKGROUND:

The fractional concentration of nitric oxide in exhaled breath (FeNO) is elevated in asthma. FeNO measurement has been proposed as a noninvasive index of disease activity. Cigarette smoking suppresses FeNO, which limits its use in smokers.

OBJECTIVE:

To identify and model short-term and long-term influences of cigarette smoking on FeNO.

METHODS:

The smoking history, FeNO, and fractional concentration of carbon monoxide in exhaled breath (FeCO) were measured in 53 subjects with asthma and 51 control subjects. A mathematical model of the short-term and long-term effects of cigarette smoking on FeNO was derived.

RESULTS:

Subjects with asthma had higher FeNO than controls ( P < .001). Smokers had increased FeCO ( P < .001). The short-term effect (hours since last cigarette) was associated with increased FeNO ( P < .01) and decreased FeCO ( P < .05). The long-term effect (years smoked) was associated with decreasing FeNO only in the subjects with asthma ( r = -0.62; P = .005). These short-term and long-term effects were independent and were combined in a model predicting FeNO, predicted log 10 FeNO = 1.23 - 0.58 e -0.34t - 0.00000103 x (lifetime cigarettes), where t = hours since the last cigarette. This gave a convincing prediction of FeNO ( r = 0.83; P < .0001).

CONCLUSION:

Short-term and long-term effects of smoking influenced the measurement of FeNO. We defined a model that describes these effects. The use of this formula may improve the value of FeNO measurements in smokers with asthma.

PMID:
15990779
DOI:
10.1016/j.jaci.2005.03.025
[Indexed for MEDLINE]

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