Personal exposure to environmental tobacco smoke: salivary cotinine, airborne nicotine, and nonsmoker misclassification

Abstract

A large study was conducted to assess exposure to environmental tobacco smoke (ETS) in a geographically dispersed study population using personal breathing zone air sampling and salivary cotinine levels. Approximately 100 self-reported nonsmoking subjects in each of 16 metropolitan areas were recruited for this investigation. Cumulative distributions of salivary cotinine levels for subjects in smoking and nonsmoking homes and workplaces exhibited a general trend of decreasing salivary cotinine levels with decreasing time spent in smoking environments. Median salivary cotinine levels for the four experimental cells in the study (product of smoking and nonsmoking home and workplaces) were comparable to those reported for a large national study of serum levels of cotinine (Third National Health and Nutrition Examination Survey, NHANES III), when the latter was corrected for expected differences between serum and saliva concentrations. However, the most highly exposed group in this study had a median salivary cotinine concentration approximately a factor of 2 greater than that of the comparable group in the NHANES III study. Misclassification rates, both simple (for self-reported nonsmokers) and complex (self-reported lifetime never smokers), were near the median of those reported for other studies. Estimated misclassification rates for self-reported lifetime never-smoking females are sufficiently high (2.95% using a discrimination level of 106 ng/ml) that, if used in the Environmental Protection Agency (EPA) risk assessment related to ETS and lung cancer, would place the lower 90% confidence interval (CI) for relative risk at nearly 1.00, i.e., no statistically significant increased risk. For the 263 most highly exposed subjects in the study whose self-reported nonsmoking status was accurate, the correlation between airborne exposure to nicotine and average salivary cotinine is so small, on an individual basis, that it makes the relationship useless for estimating exposure on a quantitative basis. When subjects are grouped according to likely categories of nicotine exposure, correlation between group median airborne nicotine exposure and salivary cotinine level increases dramatically. The comparison improves for the most highly exposed subjects, suggesting that such quantitative comparisons are useful for only those subjects who are exposed to the higher levels of ETS. However, airborne nicotine exposure for most of the subjects does not account for estimated systemic levels of nicotine, based on salivary cotinine levels.

Personal exposures to PM2.5 and polycyclic aromatic hydrocarbons and their relationship to environmental tobacco smoke at two locations in Greece

“…On the other hand, location -or season -specific cotinine levels exhibited no correlation with CHRYS / BPer ratios, while their correlation with declared ETS exposure was not consistent. However, there is still no general agreement on the degree to which cotinine can serve as a quantitative or semi -quantitative indicator of ETS exposure particularly at low levels of exposure ( Henderson et al, 1989;Coultas et al, 1990a,b;Benowitz, 1999;Jenkins and Counts, 1999 ). In particular, inter-individual differences in the nicotine metabolism may have contributed to the poor quantitative correlation of plasma cotinine with the other ETS -related parameters observed in the present study.…”

Determination of exposure to environmental tobacco smoke in restaurant and tavern workers in one US city

“…While data from a study previously conducted by the authors (Jenkins and Counts, 1999;Jenkins et al, 1996 ) have demonstrated little correlation between individual salivary cotinine levels and individual 24-h nicotine exposures, on a group basis, median or mean levels of salivary cotinine are highly correlated with median /mean ETS nicotine exposures. Judging from the group statistics for salivary cotinine in this study, for wait staff and bartenders who live with smokers, exposure to ETS outside the workplace appears to be at least as important as exposure in the workplace.…”

Measurement of Tobacco Smoke Exposure: Comparison of Toenail Nicotine Biomarkers and Self-Reports

“…Relying on toenail biomarkers to produce cutoff points for differentiating those exposed to SHS and those not exposed is also problematic because there are no population-based measures of these biomarkers. Attempts by several investigators to use cutoff points for a more widely used biomarker of SHS, such as cotinine, have failed to reach consistent values (23)(24)(25)(26).…”