Relationship between exposure to second-hand smoke in the workplace and occupational injury in the Republic of Korea

Background: Most studies in the field of smoking exposure in the workplace linked to occupational safety have only focused on active smoking. Few studies have reported that exposure to secondhand smoke in the workplace is a possible factor increasing the risk of occupational injury without considering occupational characteristics.The aim of this study was to determine the association between occupational injury and level of exposure to second-hand smoke at the workplace among Korean workers, after taking into account occupational characteristics. Method: Using data from the third Korean Working Conditions Survey, levels of exposure to second-hand smoke were categorized as none, moderate, and high. We investigated the influence of exposure to second-hand smoke on occupational injury using logistic regression analysis with stratification by sex, smoking status, smoke-free policy in the workplace, and occupational characteristics. Occupational characteristics (occupational classification, working schedule, length of working day, and co-exposure to occupational hazards in the workplace) were stratified and analyzed using logistic regression models to estimate the risk of occupational injury linked to exposure to second-hand smoke. Results: Among all participants, there was a significant dose-dependent association between risk of occupational injury and level of exposure level to second-hand smoke. After stratification by sex and smoking status, there was a significant association between risk of occupational injury and exposure level to second-hand smoke. Moreover, there was a significant relationship between exposure to second-hand smoke in the workplace and occupational injury, depending on the smoking-free policy at workplace (odds ratio [OR] in completely non-smoking workplace, 4.23; OR in non-smoking workplace with separate smoking area, 2.98; OR in smoking workplace 2.84). Additionally, there was a significant relationship between risk of occupational injury and exposure to second-hand smoke after stratification by occupational classification, working schedule, long working hours, and co-exposure to hazards in the workplace. Discussion: There was a dose–response relationship between occupational injury and exposure to second-hand smoke, even after stratification to reduce the impact of various potential confounders and after taking into account occupational characteristics.These findings provide greater insight into the effects of exposure to second-hand smoke on the working population and may direct further research and policy-making in this field.