Greater severity of new onset asthma in allergic subjects who smoke: a 10-year longitudinal study.
BACKGROUND
Little is known about the association between cigarette smoking and asthma severity. We assessed smoking as a determinant of disease severity and control in a cohort of clinic-referred allergic subjects who developed new onset asthma.


METHODS
Allergic rhinitis subjects with no asthma (n = 371) were followed-up for 10 years and routinely examined for asthma diagnosis. In those who developed asthma (n = 152), clinical severity and levels of asthma control were determined. Among these subjects, 74 (48.7%) were current smokers, 17 (11.2%) former smokers, and 61 (40.1%) never smokers.


RESULTS
When comparing current or past smokers to never smokers they had a higher risk of severe asthma in the univariate analysis, which became non-significant in the multivariate analysis. On the other hand, the categories of pack-years were significantly related to severe asthma in a dose response relationship in both the univariate and multivariate analysis: compared to 0 pack years, those who smoked 1-10 pack-years had an OR(95% CI) of 1.47(0.46-4.68), those who smoked 11-20 pack-years had an OR of 2.85(1.09-7.46) and those who smoked more than 20 pack-years had an OR of 5.59(1.44-21.67) to develop more severe asthma. Smokers with asthma were also more likely to have uncontrolled disease. A significant dose-response relationship was observed for pack-years and uncontrolled asthma. Compared to 0 pack years, those who smoked 1-10 pack-years had an OR of 5.51(1.73-17.54) and those who smoked more than 10 pack-years had an OR of 13.38(4.57-39.19) to have uncontrolled asthma.


CONCLUSIONS
The current findings support the hypothesis that cigarette smoking is an important predictor of asthma severity and poor asthma control.
Dipartimento di biomedicina clinica e molecolare-S, Marta Hospital, azienda ospedaliero-universitaria O.V.E., Università di Catania, Catania, Italy. polosa@unict.it
Riccardo
R
Polosa
Cristina
C
Russo
Pasquale
P
Caponnetto
Gaetano
G
Bertino
Maria
M
Sarvà
Tjana
T
Antic
Stefania
S
Mancuso
Wael K
WK
Al-Delaimy
D000328:Adult; D018926:Anti-Allergic Agents / Q000627:therapeutic use; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D016017:Odds Ratio; D012221:Rhinitis, Allergic, Perennial / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*; D006255:Rhinitis, Allergic, Seasonal / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D012907:Smoking / Q000453:epidemiology*; D016540:Smoking Cessation; D000074606:Smoking Prevention; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
D018926:Anti-Allergic Agents; D018927:Anti-Asthmatic Agents
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