Household environmental tobacco smoke and risks of asthma, wheeze and bronchitic symptoms among children in Taiwan.
BACKGROUND
Although studies show that maternal smoking during pregnancy increases the risks of respiratory outcomes in childhood, evidence concerning the effects of household environmental tobacco smoke (ETS) exposure remains inconsistent.


METHODS
We conducted a population-based study comprised of 5,019 seventh and eighth-grade children in 14 Taiwanese communities. Questionnaire responses by parents were used to ascertain children's exposure and disease status. Logistic regression models were fitted to estimate the effects of ETS exposures on the prevalence of asthma, wheeze, and bronchitic symptoms.


RESULTS
The lifetime prevalence of wheeze was 11.6% and physician-diagnosed asthma was 7.5% in our population. After adjustment for potential confounders, in utero exposure showed the strongest effect on all respiratory outcomes. Current household ETS exposure was significantly associated with increased prevalence of active asthma, ever wheeze, wheeze with nighttime awakening, and bronchitis. Maternal smoking was associated with the increased prevalence of a wide range of wheeze subcategories, serious asthma, and chronic cough, but paternal smoking had no significant effects. Although maternal smoking alone and paternal smoking alone were not independently associated with respiratory outcomes, joint exposure appeared to increase the effects. Furthermore, joint exposure to parental smoking showed a significant effect on early-onset asthma (OR, 2.01; 95% CI, 1.00-4.02), but did not show a significant effect on late-onset asthma (OR, 1.17; 95% CI, 0.36-3.87).


CONCLUSIONS
We concluded that prenatal and household ETS exposure had significant adverse effects on respiratory health in Taiwanese children.
Tsai
Ching-Hui
CH
Institute of Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan.
Huang
Jiun-Hau
JH
Hwang
Bing-Fang
BF
Lee
Yungling L
YL
D000293:Adolescent; D016902:Air Pollution, Indoor / Q000706:statistics & numerical data*; D001249:Asthma / Q000453:epidemiology*; D001991:Bronchitis / Q000453:epidemiology*; D002648:Child; D015897:Comorbidity; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D016016:Proportional Hazards Models; D012135:Respiratory Sounds; D018570:Risk Assessment; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013624:Taiwan / Q000453:epidemiology; D014028:Tobacco Smoke Pollution / Q000706:statistics & numerical data*; D055815:Young Adult
D014028:Tobacco Smoke Pollution