Reduced exposure to secondhand smoke at casinos in Puerto Rico after the implementation of a workplace smoking ban in 2007: a pre-post design.

OBJECTIVE: Tobacco use and the involuntary exposition to secondhand smoke (SHS) is one of the leading causes of cancer. The objective of this study was to assess the effect of the smoke free workplace ban implemented in March of 2007 in Puerto Rico on the exposure of casino workers to secondhand smoke measured in terms of fine particulate matter and cotinine level. METHODS: This study used a pre-post comparison design to measure exposure to secondhand smoke before (February, 2007) and after (December, 2007 to February, 2008) the workplace smoking ban was implemented. The samples included level of cotinine in saliva from 20 randomly sampled casino union workers and indoor concentrations of fine particulate matter (2.5 microm diameter, PM2.5) in 10 casinos located in the San Juan metropolitan area. Paired t-tests were used to test any statistically significant change in particulate matter and cotinine levels before and after the ban went into effect. RESULTS: The average PM2.5 level in San Juan metropolitan area casinos decreased by 88.5% (95% CI: 63.9%, 96.3%) and the average cotinine level for the sample of nonsmoking casino workers decreased by 52.1% (95% CI: 40.6%, 61.4%). Both reductions were statistically significant (p < 0.01). CONCLUSION: The implementation of the smoke free workplace ban in 2007 resulted in a significant reduction of the exposure to secondhand smoke to casino workers in the San Juan metropolitan area of Puerto Rico.