Intake and Uptake of Chemicals Upon Use of Various Tobacco/Nicotine Products: Can Users be Differentiated by Single or Combinations of Biomarkers?

Abstract

Summary With increasing use of new generation tobacco/nicotine products (TNPs) instead or in addition to conventional cigarettes (CCs), the question arises, whether the user of these new TNPs and CCs can be distinguished on the basis of their exposure in terms of intake and uptake of specific chemicals. For this purpose, the exposure to chemicals for users of 5 product types including CCs, HNB (heat-not-burn products), electronic cigarettes (ECs), oral tobacco products (OT, with the focus on snus), nicotine replacement therapy (NRT) products (only nicotine gum (NG) was considered in this study) was evaluated on the basis of published data. For both intake and biomarker-based uptake, 4 relative exposure levels with the assigned values from 1 (lowest exposure) to 4 (highest exposure) were defined resulting in exposure level patterns. Unique single-biomarker-based exposure levels were found for smokers (11 chemicals), vapers (1 chemical) and non-users (NU, 1 chemical). A few selected biomarkers (usually with relative levels of 3–4) were found to be sufficient for unequivocal differentiation of one user/NU group from the other 5 groups. The impact of dual-product use is also briefly discussed. [Contrib. Tob. Nicotine Res. 30 (2021) 167–198]

Assessment of nicotine delivery and uptake in users of various tobacco/nicotine products

“…As a possible reason for the deviations between model and measurement, it could be speculated that the applied nicotine yields in the models (CC: 0.5–0.8 mg/cig according to ISO; HTP: 0.5 mg/stick for all 10 users) markedly underestimate the actual, subject-derived nicotine yields. In a similar estimate of daily nicotine doses with slightly different models and application of data from the literature for consumption and products’ nicotine yields, median intakes of 11.7 and 9.0 mg/d for smokers (CC) and HTP users, respectively were reported ( Scherer et al, 2021 ), approximately twice as high as the estimated intakes in this study ( Table 2 ). When comparing the values of the variables in the two approaches, it becomes evident that for the main part the higher nicotine yields (CC: 0.6–1.7 mg/cig, HTP: 0.4–1.2 mg/stick ( Scherer et al, 2021 )) were responsible for the higher intake estimates based on literature data compared to this study.…”

“…In a similar estimate of daily nicotine doses with slightly different models and application of data from the literature for consumption and products’ nicotine yields, median intakes of 11.7 and 9.0 mg/d for smokers (CC) and HTP users, respectively were reported ( Scherer et al, 2021 ), approximately twice as high as the estimated intakes in this study ( Table 2 ). When comparing the values of the variables in the two approaches, it becomes evident that for the main part the higher nicotine yields (CC: 0.6–1.7 mg/cig, HTP: 0.4–1.2 mg/stick ( Scherer et al, 2021 )) were responsible for the higher intake estimates based on literature data compared to this study. More investigations are certainly required to substantiate this hypothesis.…”

“…An evaluation of literature data for urinary nicotine equivalents as well as cotinine in plasma and saliva of users of CC, EC, HTP, nicotine gum (NG, as a representative of NRT products), OT and of NU of any tobacco/nicotine products has recently been published ( Scherer et al, 2021 ). A comparison of the reported averages for Nequ (which have been adjusted in the review to 100 % of the excreted nicotine dose) and those for cotinine in plasma and saliva shows that the measured mean or median levels of the groups in our study ( Table 2 ) almost completely fall into the ranges of the published values for the corresponding groups (relevant literature cited in the review ( Scherer et al, 2021 )).…”

“…The nicotine intake on Day 3 of this study was estimated by applying product-specific models as described in a recent review ( Scherer et al, 2021 ) with modifications as indicated below. Instead of using ranges of values for the variables in the models, individual values for each subject were plugged in the equations.…”

“…(iii) Are there significant correlations between nicotine biomarker levels and commonly used daily consumption measures? (iv) Is there an acceptable agreement between the estimated daily intake of nicotine (by applying adjusted intake models ( Scherer et al, 2021 )) and the excretion of Nequ? If not, what are plausible reasons for the observed deviations?…”