Effects of smoking cessation on lung function and airway inflammation in smokers with asthma.
BACKGROUND
Active smoking in asthma is associated with worsening of symptoms, accelerated decline in lung function, and impaired response to corticosteroids.


OBJECTIVE
To examine the short-term effects of smoking cessation on lung function, airway inflammation, and corticosteroid responsiveness in smokers with asthma.


METHODS
Smokers with asthma were given the option to quit or continue smoking. Both groups underwent spirometry and induced sputum at baseline and at 1, 3, and 6 wk. Cutaneous vasoconstrictor response to topical beclometasone, airway response to oral prednisolone, and sensitivity of peripheral blood lymphocytes to corticosteroids were measured before smoking cessation and at 6 wk.


RESULTS
Of 32 subjects recruited, 11 opted to continue smoking (smoking control group). Of 21 subjects who opted for smoking cessation, 10 quit smoking for 6 wk (quit group). In the comparison of quitters with smokers at 6 wk, the mean (confidence interval [CI]) difference in FEV(1) was 407 ml (21, 793), p = 0.040, and the proportion of sputum neutrophils was reduced by 29 (51, 8), p = 0.039. Total cutaneous vasoconstrictor response score to topical beclometasone improved after smoking cessation with a mean (CI) difference of 3.56 (0.84, 6.28), p = 0.042, between quitters and smokers. There was no change in airway corticosteroid responses after smoking cessation.


CONCLUSIONS
By 6 wk after smoking cessation, subjects who quit smoking had achieved considerable improvement in lung function and a fall in sputum neutrophil count compared with subjects who continued to smoke. These findings highlight the importance of smoking cessation in asthma.
Chaudhuri
Rekha
R
FRCP, Department of Respiratory Medicine, Division of Immunology, Infection and Inflammation, University of Glasgow and Western Infirmary, Glasgow G11 6NT, UK.
Livingston
Eric
E
McMahon
Alex D
AD
Lafferty
Jane
J
Fraser
Iona
I
Spears
Mark
M
McSharry
Charles P
CP
Thomson
Neil C
NC
D000328:Adult; D001249:Asthma / Q000453:epidemiology / Q000276:immunology / Q000503:physiopathology*; D002452:Cell Count; D015897:Comorbidity; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D005938:Glucocorticoids / Q000494:pharmacology; D006801:Humans; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012907:Smoking / Q000453:epidemiology / Q000276:immunology / Q000503:physiopathology*; D016540:Smoking Cessation; D013183:Sputum / Q000166:cytology
D005938:Glucocorticoids