To the best of our knowledge, this is the first study to test the mediating role of alcohol drinking in the association between smoking and SHS exposure. This study was conducted with a large population-based sample. The results support our hypotheses.
There is consistent evidence regarding the correlation between smoking and alcohol drinking or SHS exposure. However, although smoking prevalence has traditionally been considered a predictor of SHS exposure, it has not been fully clarified whether alcohol use acts as a mediator14,15,21. Our study confirms the proven relationships between smoking and SHS exposure and clarifies the mediating role of alcohol drinking in the relationship between smoking and SHS exposure.
In addition, most prior research examining the relationship between smoking and alcohol use behaviours has used general information. These studies consistently found a positive correlation22–23. However, determining whether these same associations exist for specific domains, such as the workplace, and whether associations differ based on demographic variables could provide more relevant and potentially actionable information for policy makers.
In our study, we found a lower smoking prevalence for males (40.5%) compared to the male smoking prevalence shown in the 2018 Chinese Adult Tobacco Survey (50.5%)24. A possible explanation is that our participants were all from different companies. Their educational attainment was higher than that of the general population; for example, 71.3% of respondents had achieved college graduation. A large number of studies have shown an inverse association between smoking and educational attainment.19, 25–26
The full sample SEM model showed that SF workplace policy was associated with lower SHS exposure; however, this policy had only a limited impact on drinking behaviour. However, subgroup analysis showed different results. A SF policy can have a direct influence on smokers’ drinking behaviour, which in turn works in conjunction with the impact on the smoking amount to contribute to a positive quitting intention. Therefore, it is suggested that the objective of reducing SHS exposure can be achieved through SF policies. However, in terms of triggering stronger quitting intentions or maximizing the impact of SHS exposure reduction, companies should integrate multilevel health promotion, such as alcohol drinking intervention programmes, into their employee care system.
The model of this study has some potential public health implications as it demonstrated the potential impact of alcohol use on health behaviour and the possible relationship for tobacco control policy. On the one hand, our results indicate a spillover effect of SF workplace policy, showing that SF workplace policies are associated not only with lower SHS exposure but also with reduced drinking behaviour. Moreover, our study calls for effective interventions for alcohol use, which may influence other health policy implementation outcomes. This evidence can be used to lobby policymakers to implement an effective integrated health intervention approach.
However, this is a relatively new research topic, and we acknowledge that our findings are limited by the cross-sectional design. Future studies need to explore other potential mediators between smoking and SHS exposure and other possible factors in the pathway between SF workplace policy and SHS exposure and quitting intention. For example, the channel of alcohol use only mediated a maximum of 14.1% of the total effects. What are the other parts of the mechanism? Does a stricter smoking ban policy have a more significant effect on controlling drinking behaviour? These issues have strong policy implications.
This study has several limitations. First, as mentioned, since we employed a cross-sectional design, we cannot infer causality. Second, selection bias might have existed due to the self-selection of participants in the ABWMC programme by company-level decision. However, because the participants were recruited from different parts of China and belonged to different types of companies, it is believed that the overall findings are meaningful. Third, other critical and omitted variables might exist that could affect the role of alcohol consumption in the model, such as smoking harm awareness and SHS harm awareness.