Accurate verification of nicotine and tobacco product use or abstinence using a multi-biomarker approach

Cigarette smokers are exposed to over 7,000 chemicals, including many toxic and carcinogenic agents. Alternative non-combustible nicotine products considerably reduce exposure to harmful constituents. Extensive research on biomarkers of potential harm is crucial to assess smoking’s early health impacts and harm reduction upon quitting or switching to alternative products. However, such clinical trials are constrained by poor verification of self-reported product use as common procedures using exhaled carbon monoxide (eCO) and cotinine strip tests are limited by short detection period and non-specificity, respectively. Therefore, product-use specific biomarkers of exposure (BoE) are needed for accurate biochemical verification in studies evaluating the health impact of new products, such as electronic cigarettes. We conducted a cross-sectional study in 180 participants consisting of current, former and non-smokers and applied several BoEs to verify the participants’ use behavior. Our multi-biomarker approach monitored exposure to nicotine, tobacco-specific nitrosamines, acrylonitrile and propylene glycol (PG), which were significantly elevated in the current smoker group except PG, identifying six non-compliant subjects (4 current, 1 former and 1 non-smoker). The proposed biomarker panel outperformed eCO and was also able to distinguish distinct use patterns such as vaping versus smoking, thereby enhancing data accuracy. Moreover, biochemically determined exposure variables such as carboxyhemoglobin and cotinine showed stronger correlations with BoEs than self-reported cigarette consumption. Therefore, the suggested panel is particularly valuable for non-controlled studies, where reliance on self-report can bias outcomes. Implementing the proposed verification strategy can improve study validity and strengthen evidence on the health impacts of switching to alternative products.