Comparison of ETS Nicotine Exposure to Total Nicotine Exposure. Willard R. Chappell and Lawrence B. Gratt, IWG Corp., 2241 Kettner Blvd., Suite 220, San Diego, CA 92101
Exposure and pharmacokinetic parameters are used to estimate the daily nicotine dose from environmental tobacco smoke (ETS) exposure (using personal monitor data) and from all sources (using salivary cotinine, a metabolite of nicotine). The air nicotine exposure data and the salivary cotinine data are from a recent survey by Oak Ridge National Laboratory. The reported cumulative exposures allow us to generate distributions for the estimated nicotine doses. Data from the literature is used to develop distributions for parameters such as breathing rate and pharmacokinetic parameters. @RISK software is used to generate probability distributions for the ETS and total nicotine doses. When these estimates are compared it is found that the total nicotine estimate derived from salivary cotinine data is significantly greater than the ETS-estimated dose. This indicates that there might be other nicotine sources, such as diet, which are significant compared to the measured ETS exposure. Previous work has indicated tea consumption alone contributes a mean daily nicotine dose of 11.5 mg. Another possible explanation is that there is large interpersonal variability in nicotine metabolism. Either way, it appears that salivary cotinine is not a good biomarker for ETS exposure as has been previously assumed.