Active smoking, environmental tobacco smoke and bronchitic symptoms among adolescents in Taiwan: a prospective cohort study.
OBJECTIVE
The study investigates the association between active smoking, exposure to environmental tobacco smoke (ETS) and the development of bronchitis and bronchitic symptoms among adolescents.


METHODS
A prospective cohort study was conducted with 4134 adolescents aged 12-14 from the Taiwan Children Health Study in 14 communities in Taiwan since 2007. Parents or guardians completed written questionnaires regarding demographic information, household ETS and respiratory symptoms at baseline. The adolescents themselves completed identical questionnaires on respiratory outcomes in the 2009 survey. Associations between active smoking, exposure to ETS and the 2-year incidence of respiratory outcomes were analyzed by multiple Poisson regression models, taking overdispersion into account.


RESULTS
Active smoking was associated with an increased risk of developing chronic cough and chronic phlegm. We found significant dose-response associations between the duration of smoking, the numbers of cigarettes and the onset of bronchitic symptoms. Exposure to ETS was a significant risk factor for the development of chronic cough. Among asthmatic adolescents, exposure to ETS was associated with an additional risk for the onset of chronic phlegm.


CONCLUSIONS
This study demonstrates that active smoking and exposure to ETS are associated with higher risks for developing bronchitic symptoms among adolescents.
Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan; Department of Family Medicine, Taipei City Hospital, Taipei, Taiwan. Electronic address: airobo33@gmail.com.
Jer-Min
JM
Chen
Departiment of Occupational Safety and Health, College of Public Health, China Medical University, Taichung, Taiwan. Electronic address: bfhwang@mail.cmu.edu.tw.
Bing-Fang
BF
Hwang
Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan; Department of Family Medicine, Taipei City Hospital, Taipei, Taiwan. Electronic address: melisa26@gmail.com.
Yang-Ching
YC
Chen
Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan; Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan. Electronic address: leolee@ntu.edu.tw.
Yungling Leo
YL
Lee
D000293:Adolescent; D001249:Asthma / Q000453:epidemiology*; D001991:Bronchitis / Q000453:epidemiology*; D002648:Child; D002908:Chronic Disease; D015897:Comorbidity; D003371:Cough / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012907:Smoking / Q000453:epidemiology*; D013624:Taiwan / Q000453:epidemiology; D014028:Tobacco Smoke Pollution / Q000009:adverse effects / Q000706:statistics & numerical data*
D014028:Tobacco Smoke Pollution
Adolescents; Asthma; Bronchitis; Smoking; Tobacco smoke pollution