Main findings of this study
This study has found that the majority of casino workers in London who participated in the survey reported at least one sensory and respiratory irritation symptom in the previous four weeks. Reporting the presence of irritation symptoms was most strongly associated with reporting the highest level of exposure to SHS at work. The apparent link between exposure to SHS and respiratory and sensory irritation symptoms is strengthened by the suggestive dose-response relationship between self-reported frequency and intensity of exposure and both symptom types.
The association between high levels of sensory and respiratory irritation symptoms and exposure to SHS is consistent with that found in other studies of workers. Evidence is particularly strong in the studies of bar workers that demonstrated decreases in prevalence of symptoms after the introduction of smoke-free policies. Most decreases were statistically significant compared to baseline [20–24]. As reported elsewhere, many casino workers in this study believed that SHS affected their health, with 57% (315/558) believing that their health had been affected by exposure to SHS at work .
Our research demonstrates that among this sample of casino workers, the prevalence of respiratory and sensory irritation symptoms is generally higher than those reported in studies of bar workers and the previous study of casino workers. This could be because of differing exposure to SHS between casino and bar environments. As the studies of bar workers suggest that workers report similar frequency of exposure to SHS whilst in the workplace, the higher prevalence may relate to longer working hours and greater intensity of exposure in casino workers. Casino workers are in their workplace for a greater proportion of the working week, working an average 38 hours per week compared to a range of 21–40 hours per week for bar workers [20–23]. Unlike pubs or bars, casinos often do not have windows or other sources of fresh air and our previous research has revealed that casino workers are often face to face with several smokers at gaming tables for significant periods of time . The difference in prevalence of symptoms between our study and the previous research on casino workers may be because of the smaller sample size in that study and/or the fact that 5% of the casino workers reported that smoking was banned at their workstation (suggesting that this workforce may have been exposed to less SHS than the London sample) .
As noted, our study also found associations between symptoms and other variables. The association between working for more hours per week in the casino and respiratory irritation symptoms is logical, as this could be viewed as an alternative measure of exposure; suggesting a higher frequency of exposure to SHS during the working day. However there was little variation in average hours worked in casinos between workers, which may explain why average hours worked was only weakly associated with respiratory symptoms and not associated with sensory irritation symptoms. The association between smoking status and sensory irritation symptoms (but not respiratory symptoms) may be because sensory symptoms are primarily associated with SHS (of which smokers might be less affected), while respiratory symptoms are related more closely to the effects of active smoking. The study of bar workers in Wisconsin also found this association between smoking status and symptoms . It is not clear why there is a link between having degree or higher educational qualifications and reporting sensory irritation symptoms.
What this study adds
To our knowledge this is the first study to estimate prevalence of sensory and respiratory irritation symptoms among a large sample of casino workers. As most studies of respiratory and sensory irritation symptoms have focussed on bar workers, it offers a valuable insight into how exposure to SHS affects other exposed workforces. This is particularly important when those workforces are at risk of being excluded from smoke-free legislation. The sample size of 559 workers is larger than that of previous studies of bar and casino workers. As such, the paper provides further evidence using a larger population that exposure to SHS in the workplace is associated with reporting of both sensory and respiratory irritation symptoms.
The lack of other such studies might be in part due to the difficulties in accessing casino workers. We have already outlined how the casino companies refused to co-operate in our research, and it is likely that other such employers around the world may be reluctant to allow access to employees for fear of bad publicity and worker unrest. Indeed, without the option of sampling through trade unions, this workforce would not have been accessible to us. It may be that in other parts of the world, trade unions offer a route to access otherwise hard to reach working groups such as casino workers. In the debates on smoke-free legislation around the world, it is vital that the voices of those workers who are exposed to high levels of SHS at work are heard.
Limitations of this study
This study has several limitations. The main limitation relates to the potential of responder bias among the sample of casino workers. As outlined, the survey had a response of 36%. Unfortunately, other than gender, the unions held no other summary data on their members against which to assess the representativeness of the responders to the targeted unionised population. It was also not possible to assess how responders compared to the wider casino workforce in London, due to being unable to obtain such data from the casino companies.
Although the proportion of smokers among the respondents (22%) is comparable to national UK estimates of smoking prevalence, there is likely to be under-representation of smokers in the study results . A previous study in London estimated that 37% of manual workers were current smokers, and casino workers are likely to fall in this group . An underestimation of smokers among the respondents would affect overall estimates of the prevalence of irritation symptoms, as smoking status is an important variable in the logistic regression. However, it is not possible to determine whether there is under-representation, as data on smoking prevalence among casino workers in the United Kingdom is not collected either nationally or by the trade unions.
It is possible that those who were suffering from ill-health that they associated with exposure to SHS were more likely to respond to the survey. In this scenario, the prevalence of respiratory and sensory irritation symptoms among casino workers may be overestimated. Unfortunately it is not possible to determine if this occurred. Other studies of workers also note weaknesses relating to possible responder bias [20–23]. These studies, like ours, lacked the necessary baseline data to assess whether such bias was likely.
Our study relied on self-reports of exposure to SHS. This measures perception of exposure to SHS, not actual exposure. Existing evidence suggests that while workers and others are usually able to report accurately on whether they are exposed to SHS or not, quantifying the extent of their exposure is more problematic . In order to validate the self-reported measures of exposure, an objective measure of exposure to SHS could have been gathered from each worker, such as a before- and after-shift cotinine sample. However, resource limitations meant that this was not feasible.
Our study and previous studies have used respiratory and sensory irritation symptoms as indicators of acute health effects of SHS. Symptoms such as coughing and having a sore throat and runny nose could also be associated with other causes, such as bacterial and viral infections. We did not control for the presence of cold or other respiratory conditions. However, the previous study of casino workers did find an association between exposure to SHS and symptoms, after adjusting for presence of cold and other respiratory conditions . In addition, the observed decreases in respiratory and sensory irritation symptoms in the bar worker studies following the introduction of smoke-free legislation (and accompanying decreases in cotinine levels) strengthens the likelihood that SHS exposure does play a large role in the prevalence of these symptoms.
Implications of the findings
The existing evidence that SHS is harmful to health is already sufficient to demonstrate the need for smoke-free legislation that protects all workers, including those in casinos. In fact, the recent legislation in England now means that the casino workers surveyed as part of this research are now protected from SHS at work, as are those workers in countries such as Ireland, Italy, and Norway [11–13, 15]. Unfortunately, the decision to exclude casino workers from smoke-free legislation in some parts of the United States and the creation of exempted areas in casinos in Australia demonstrates that some policy makers continue to ignore the health needs of the most vulnerable workers.
The findings reported here emphasise that while casino workers represent a working group that is most likely to be excluded from smoke-free legislation, they report high levels of ill-health associated with exposure to SHS. Unless smoke-free legislation is comprehensive, it will fail in its aim to protect workers and improve public health; instead, widening health inequalities by leaving the most vulnerable workers at risk. Inequalities will not only widen because of the direct health effects of exposure to SHS, as it is known that when smoke-free policies are introduced in workplaces, smokers are more likely to cut down or quit completely . Those smokers working in settings that are excluded from legislation will be denied this benefit.