Exposure to Secondhand Smoke Outside of a Bar and a Restaurant and Tobacco Exposure Biomarkers in Non-smokers
Gideon St.Helen, J. Thomas Bernert, Daniel B. Hall, Connie S. Sosnoff, Yang Xia, John R. Balmes, John E. Vena, Jia-Sheng Wang, Nina T. Holland, Luke P. Naeher
Background: With an increase in indoor smoking bans, many smokers smoke outside establishments and near their entrances, and this has become a public health concern.
Objectives: To characterize the exposure of non-smokers to secondhand smoke (SHS) outside a restaurant and bar in Athens, Georgia, where indoor smoking is banned, using salivary cotinine and urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-bu?tanol (NNAL).
Methods: We assigned twenty-eight subjects to outdoor patios of a restaurant and a bar and an open-air site with no smokers on three weekend days in a crossover study; subjects visited each site once and stayed for 3 hours. We collected saliva and urine samples immediately before and after visits (post-exposure) and on the following morning, and analyzed samples for cotinine and total NNAL, respectively. Regression models were fit and changes in biomarkers were contrasted between locations.
Results: Post-exposure and pre-exposure geometric mean salivary cotinine concentrations differed by 0.115 ng/mL (95% CI: 0.105, 0.126) and 0.030 ng/mL (95% CI: 0.028, 0.031) for bar and restaurant visits, respectively. There were no significant post- and pre-exposure differences in cotinine levels after control site visits, and changes after bar and restaurant site visits were significantly different from changes after control site visits (p<0.001). Results comparing next-day and pre-exposure salivary cotinine levels were similar. Next-day creatinine-corrected urinary NNAL concentrations also were higher than pre-exposure levels following bar and restaurant visits (1.858 pg/mL 95% CI: 0.897, 3.758 and 0.615 pg/mL 95% CI: 0.210, 1.761, respectively), and were significantly different from changes following control visits (p=0.005).
Conclusion: Salivary cotinine and urinary NNAL increased significantly in non-smokers following outdoor SHS exposure, indicating that such exposures may increase risks of health effects associated with tobacco carcinogens.