Cross-sectional and prospective associations between passive smoking and respiratory symptoms at the workplace.
OBJECTIVE
The purpose of the study is to investigate the cross-sectional and prospective relation between workplace secondhand smoke (SHS) exposure and respiratory symptoms.


METHODS
Cross-sectional data for workplace SHS exposure and respiratory symptoms were collected by using random digit dialing from 7336 never-smoking Hong Kong workers 15 years or older in 1997 to 1998. In the 2000 to 2001 follow-up, 2213 workers who remained never smoking, had the same SHS exposure status, worked at the same job for at least 2 years, and were not exposed to SHS at home at follow-up were included for prospective analysis.


RESULTS
Cross-sectionally, SHS was associated significantly with frequent colds, cough and phlegm, throat problems, and the presence of any respiratory symptoms with adjusted odds ratios of 1.89 (95% confidence interval [CI], 1.66-2.15), 1.65 (95% CI, 1.35-2.02), 1.88 (95% CI, 1.63-2.15), and 1.96 (95% CI, 1.75-2.20) at baseline, each having significant linear associations with duration of exposure. SHS was not associated with rhinitis. Prospectively, consistent SHS exposure increased the risk for cough and phlegm and any respiratory symptoms by 48% (12% to 97%) and 54% (13% to 109%), respectively.


CONCLUSIONS
This first non-Western population-based prospective study shows that workplace SHS exposure is associated significantly with frequent respiratory symptoms, both cross-sectionally and prospectively, thus providing strong evidence that the association is causal.
Ho
Sai Yin
SY
Department of Community Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong.
Lam
Tai Hing
TH
Chung
Siu Fung
SF
Lam
Ting Pui
TP
D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure; D011446:Prospective Studies; D012140:Respiratory Tract Diseases / Q000453:epidemiology* / Q000503:physiopathology; D014028:Tobacco Smoke Pollution; D017132:Workplace
D014028:Tobacco Smoke Pollution