Evaluation of biomarkers of exposure to selected cigarette smoke constituents in adult smokers switched to carbon-filtered cigarettes in short-term and long-term clinical studies

Abstract

Cigarette smoke is a complex aerosol that includes a gas vapor phase and a particulate phase. Inclusion of activated carbon in the cigarette filter can reduce some of the gas-phase smoke constituents implicated as toxicologically relevant. The present study evaluated exposure to selected gas-phase constituents when adult smokers switched to prototype cigarettes with a highly activated carbon filter. Smokers (N = 160) in two separate studies were randomized to continue to smoke conventional cigarettes (either a 6-mg or 11-mg FTC tar product), to smoke test cigarettes containing carbon filters (comparable tar levels), or to stop smoking. After completing 8 days in controlled smoking conditions (short-term studies), smokers had the option to continue in 24-week long-term ambulatory studies with unrestricted smoking. Urinary excretion of mercapturic acid metabolites of 1,3-butadiene, acrolein, and benzene; nicotine and five of its metabolites, total NNAL, and 1-hydroxypyrene were measured at baseline in the conventional cigarette group, in all groups in the short-term studies, and every 4 weeks in the long-term studies. In the short-term studies, statistically significant reductions (>70%, p<.001) in gas-phase biomarker levels were observed in the test cigarette group for both tar level products compared with the conventional cigarette group. These reductions were similar to those observed in the stop-smoking groups. The reductions continued consistently (p<.001) throughout the long-term studies. Switching to test cigarettes minimally affected the particulate-phase biomarkers. Statistically significant and consistent reductions in selected gas vapor phase biomarkers were observed when smokers switched to activated carbon filter cigarettes.

Determination of methyl-, 2-hydroxyethyl- and 2-cyanoethylmercapturic acids as biomarkers of exposure to alkylating agents in cigarette smoke

“…Group 3 (n = 20) stopped smoking for the remainder of the study (SS2). Details of this study design, subject characteristics and cigarette characteristics have been reported [18].…”

Biomarkers of Exposure among U.S. Cigar Smokers: An Analysis of 1999–2012 National Health and Nutrition Examination Survey (NHANES) Data

“…Biomarkers of tobacco exposure or potential harm have previously been analyzed for cigarette smokers (16)(17)(18)(19)(20)(21)(22), but less information is available about biomarkers associated with cigar consumption. It has been shown that cigar smoke contains significantly higher concentrations of toxic and carcinogenic constituents such as tobaccospecific N-nitrosamines (TSNA), carbon monoxide, and benzene than does cigarette smoke (6).…”

Reference change values to assess changes in concentrations of biomarkers of exposure in individuals participating in a cigarette-switching study

“…Twenty-one known BoEs for tobacco smoke toxicants with validated analytical methods [13,[23][24][25][26][27][28] were assessed in total (Supplemental Data, Table 1). Levels were reported as quantities of BoEs excreted over 24 h, and were calculated as products of the concentrations in urine and the volumes of urine produced by the subjects over the collection period.…”

“…For example, BoE levels indicating exposure to nitrosamines were lower in smokers of cigarettes with low tobacco-specific nitrosamine yields than in those who smoke cigarettes with higher yields [12], and reductions were seen in BoEs to some vapourphase toxicants following a switch from cellulose acetatefiltered cigarettes to carbon-filtered cigarettes [13].…”