This study examined the prospective association between physical exertion at work and tobacco, cannabis, alcohol use, and a diet rich in sugar and fat among employees from a large population-based cohort while taking into account sociodemographic factors and depressive symptoms. Overall, high physical exertion at work was positively associated with tobacco and cannabis use, as well as with the consumptions of a diet that is rich in sugar and fat. Regarding tobacco use, when exposed to high physical exertion at work, former smokers were more likely to relapse and current smokers were more likely to increase their consumption with dose-dependent relationships.
This study has some strengths. First, we used the RPE Borg scale which is a well-validated standardized tool to assess physical exertion at work 20. Second, we had the necessary data to adjust the analyses for potential confounders, and sufficient power to run stratified analyses. This study has also some limitations. First, although such a large sample of population-based workers studies a large heterogeneity of different work settings, participants in are not representative of the general population, even when randomly recruited. Thus, our results should be extrapolated with caution to other settings. Second, we cannot exclude the possibility of residual confounding since some contributing factors such as personality traits or other work factors like long-working hours, have not been measured. Third, even if we performed stratified analyses according to sociodemographic factors, we could not rule out that our associations concern only certain occupations. Fourth, the absence of quantities of fat and sugar intakes limited our ability to calculate energy intakes from these macronutrients and quantify their association with physical exertion at work. However, we do not believe this information may bias our finding as the frequency of consumption provides good information on nutrient intakes.
High physical exertion was associated with tobacco, cannabis use and diet rich in sugar and fat but not with alcohol use. Prior studies were mainly cross-sectional and none of them focused on physical exertion at work 23–27. However, our findings are overall in accordance with prior findings showing increased risks of substance use in employees experiencing difficult working conditions (e.g., high job demand, work stress and work-related musculoskeletal disorders) 28–30. We may hypothesize that work-related physical exertion could increase the need of more frequent breaks as well as close ties with peers to better cope with the intensity of work 31. However, these situations may increase the likelihood of smoking 32. Furthermore, physical exertion may promote sleep disorders 33, and/or physical pain 34, that one can try to alleviate by using cannabis. No associations were found with alcohol use. Even if this result has to be confirmed in future studies with longer duration of follow-up and measurement of alcohol use disorder, patterns of alcohol use mainly rely on other occupational factors (e.g., business lunches and machine driving) and may not be considered by employees as a good way to deal with physical exertion by seeking relaxation and rest rather than festive situations and disinhibition.
Two cross-sectional studies found that a detrimental work environment (measured by physical and biomechanical factors) was associated with obesity (BMI ≥ 30kg/m2) 28,29. Employees who are experiencing a tiring job could tend to cope with this situation by increasing or modifying their eating habits into comfortable foods (with a high fat and sugar content). Moreover, access to healthy foods may not always be available or easy at work, especially when exposed to difficult working conditions, making it thus harder to optimize food intake. Finally, our findings are overall in accordance with the propensity to use substance and to overconsume sugar and fat to cope with stressful life events 28,29,35−38.
When stratified by age and sex, we did not find any differences across age categories. Hence, we believe that the probability of having less healthy individuals more likely to be unemployed than are healthy individuals to be low. Hence, the associations are unlikely to be explained by a “healthy worker effect” where older employees have better resilience regarding their work exposures 39.
However, we found gender differences regarding tobacco and cannabis use. The lack of association in women while studying tobacco relapse is most likely the result of a reduction in statistical power. The lack of association in men while studying cannabis use needs further studies, especially by considering other potential confounders.
In conclusion, high perceived physical exertion at work was positively associated with tobacco and cannabis use and diet rich in sugar and fat. Regarding tobacco use, dose-dependent relationships were found, and when exposed to high physical exertion at work, former smokers were more likely to relapse whereas current smokers were less likely to quit. These associations should be considered when designing preventive strategies regarding poor health outcomes associated with physical exertion at work. For example, promoting other options to have a break than smoking, informing on healthy strategies to manage sleep disorders in the workplace. Furthermore, physical exertion, which can be shortly and easily assessed in occupational health, may be an indicator of the risk of unhealthy behaviors. Thus, employees exposed to such difficult working conditions should benefit from a standardized screening for substance use and deleterious eating behaviors, and to be referred to specialized care if needed. Since the present study did not find any substantial moderating effect of sociodemographic factors and depressive symptoms, these information and prevention strategies should be spread in all the exposed employees. Future studies should examine the benefits of such interventions on reducing the likelihood of unhealthy behaviors in employees.