Workplace second-hand smoke exposure and its association with respiratory symptoms: Findings from cross-sectional surveys 2015–2020

Objectives

We investigated the prevalence and associated factors of exposure to secondhand smoke (SHS) at workplaces from 2015 to 2020, 8+ years after the expansion of smoke-free areas, including all indoor workplaces in Hong Kong since 2007, and its association with respiratory symptoms in Chinese adults.

Study design

Population-based survey.

Methods

13,048 working respondents (aged 15+ years) from 6 waves of population-based random-digit telephone surveys (2015–2020) were included. Information on sociodemographic factors, smoking status, and SHS exposure at workplaces were collected. 4585 respondents were randomly selected to report their recent respiratory symptoms. Log-binomial regressions assessed factors associated with SHS exposure at workplaces and the association between SHS and respiratory symptoms, adjusting for sociodemographic factors.

Results

24.8 % of respondents reported SHS exposure at workplaces in the 7 days preceding the survey. Male, older age, lower education level, work outdoors, work both outdoors and indoors, work in vehicles, work as service and sales workers, and work as manual laborers were associated with SHS exposure at workplaces (all P < 0.05). SHS exposure at workplaces was associated with respiratory symptoms in never smokers (Adjusted prevalence ratio (APR) 1.34, 95 %CI 1.00 to 1.81) and ex-smokers (APR 1.34, 95 %CI 1.02 to 1.77), with dose-response relationships.

Conclusion

Eight to thirteen years after banning smoking at all indoor workplaces, SHS exposure at workplaces was prevalent in outdoor occupations. Exposure to SHS at workplaces was associated with self-reported respiratory symptoms in never and ex-smokers. Policymakers should consider continuously expanding smoke-free areas to more outdoor public places.