The results of this study are consistent with others that we have conducted examining SHS exposure levels in patrons and workers in restaurants and bars (29
). In one of the prior studies, total NNAL and total cotinine were measured in workers at bars and restaurants that allowed smoking (30
). Twenty-four hour urine collections were obtained during and after their work day and during a non-work day. The results showed that for total cotinine the median difference was 7.5 ng/mL and the mean difference was 11.6 ng/mL on work days compared to non-work days. The values were 0.025 pmol/mL and 0.033 pmol/mL, respectively, for total NNAL. In another study, total NNAL and cotinine levels of 32 non-smoking workers in bars and restaurants that prohibited smoking were compared with 52 non-smoking employees of bars and restaurants where smoking was allowed (31
). The employees of restaurants and bars where smoking was permitted were significantly more likely to have detectable levels of urinary total NNAL as well as urinary total cotinine and to experience 3 times greater increase in levels of total NNAL and 10 times greater increase in total cotinine levels compared to workers in similar venues that did not allow smoking.
It is notable that 8 of the subjects in the current study did not have detectable levels of total NNAL prior to the ban. Five of these eight subjects were employees of 2 restaurants. The low levels of total NNAL may have been a function of the level of exposure on the day that they collected urine samples; perhaps they had higher exposure on other days. The 57% to 77% reductions in total NNAL levels is consistent with studies that have shown reductions in particulate matter or respirable suspended particles that range from 68% to 99%, with the majority of studies showing greater than 80% reductions (10
). The percent reduction in total NNAL exceeds the 30% coefficient of variation observed across repeated total NNAL measurements in smokers, according to our unpublished data, but no similar data are available for nonsmokers exposed to SHS.
Unlike total NNAL, the majority of subjects did have detectable levels of total cotinine in their urine prior to the ban. Prior studies using cotinine as an outcome measure demonstrated a reduction in levels pre and post-ban that ranged from 43% to 95% with a mean reduction of about 76% (4
). These observations are in line with the approximately 80% reduction observed in total cotinine in this study and these findings are consistent with the 83% and 98% reduction observed in air nicotine concentrations observed before and after bans (15
). Similar to total NNAL, the coefficient of variation observed across repeated total cotinine measurements in smokers is approximately 30%, according to our unpublished data, but no data are available for nonsmokers exposed to secondhand smoke.
The levels of NNK and nicotine exposure reported here are significantly less than found among smokers. However, in spite of these low exposure levels, SHS is believed to contribute to 3000 lung cancer deaths and more than 35,000 coronary heart disease deaths per year in the U.S. (1
) and can negatively affect the health outcomes of individuals who already have a disease (34
With accumulating findings such as those observed in this study, there is increasingly less challenge to the concept that reducing tobacco smoke in hospitality venues will reduce employee exposure to tobacco toxicants and ultimately reduce health risk. Consistent with significant reductions in exposures, smoke-free bans have resulted in a rapid impact on reduction in hospital admissions for acute myocardial infarctions in the community (35
) as well as decreased respiratory symptoms and increased pulmonary function in bartenders (13
) or other hospitality workers (23
) and improved systemic inflammatory markers (24
). Not only do these laws provide health benefits to employees and patrons, smoke-free workplace bans provide benefits to other groups. Rates of smoking initiation after bans have been shown to be reduced in adolescents (39
). A review of 26 studies before and after smoking bans estimated that bans resulted in a reduction in the prevalence of smoking by 3.8%, reduction in the number of cigarettes/day by 3.1 and an estimated drop in US consumption of 4.5% (40
). In addition, smokers are more likely to make a quit attempt and be successful (41
). Studies also show minimal economic problems associated with bans (43
A limitation of this study is that the subjects were self-selected. They were recruited by local tobacco control leaders who support and in some cases work to advance comprehensive smoke-free workplace policies. It is possible that a participant may have altered his or her behavior to influence the study outcome. However, our results are consistent with other published studies on restaurant and bar workers showing decreased levels of cotinine and other tobacco related exposure biomarkers after smoking bans went into effect (11
). Additional limitations included the lack of sensitivity in our analytic methods to adequately determine the concentrations of NNAL in all workers before the ban and only a single measurement point before and after the ban.
In summary, it is critical for states and communities to continue to support strict restrictions on smoking in workplaces to ensure that all employees, including those in the hospitality industry, are guaranteed a safe work environment, free of exposures to carcinogens and toxicants that enhance the risk of cancer, cardiovascular and pulmonary disease.