Urinary concentrations of monohydroxylated polycyclic aromatic hydrocarbons in adults from the U.S. Population Assessment of Tobacco and Health (PATH) Study Wave 1 (2013–2014)

Abstract

Background: Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants formed from incomplete combustion of organic matter; some PAHs are carcinogens. Smoking, diet, and other activities contribute to exposure to PAHs. Exposure data to PAHs among combustible tobacco product users (e.g. cigarette smokers) exist; however, among non-combustible tobacco products users (e.g., e-cigarette users), such data are rather limited. Objectives: We sought to evaluate exposure to PAHs among participants in Wave 1 (2013–2014) of the Population Assessment of Tobacco and Health (PATH) Study based on the type of tobacco product (combustible vs non-combustible), and frequency and intensity of product use. Methods: We quantified seven PAH urinary biomarkers in 11,519 PATH Study participants. From self-reported information, we categorized 8327 participants based on their use of tobacco products as never-tobacco user (never user, n = 1700), exclusive current established combustible products user (combustible products user, n = 5767), and exclusive current established non-combustible products user (non-combustible products user, n = 860). We further classified tobacco users as exclusive cigarette user (cigarette user, n = 3964), exclusive smokeless product user (SLT user, n = 509), and exclusive e-cigarette user (e-cigarette user, n = 280). Last, we categorized frequency of product use (everyday vs some days) and time since use (last hour, within 3 days, over 3 days). We calculated geometric mean (GM) concentrations, and evaluated associations between tobacco product user categories and PAH biomarkers concentrations. Results: Combustible products users had significantly higher GMs of all biomarkers than non-combustible products users and never users; non-combustible products users had significantly higher GMs than never users for four of seven biomarkers. For all biomarkers examined, cigarette users had the highest GMs compared to other tobacco-product users. Interestingly, GMs of 2-hydroxyfluorene, 3-hydroxyfluorene and Σ2,3-hydroxyphenanthrene were significantly higher in SLT users than in e-cigarette users; 3-hydroxyfluorene and 1-hydroxypyrene were also significantly higher in e-cigarette and SLT users than in never users. Everyday cigarette and SLT users had significantly higher GMs for most biomarkers than some days’ users; cigarette and SLT users who used the product in the last hour had significantly higher GMs of most biomarkers than other occasional cigarette or SLT users respectively. By contrast, everyday e-cigarette users’ GMs of most biomarkers did not differ significantly from those in some days’ e-cigarette users; we did not observe clear trends by time of last use among e-cigarette users. Conclusions: Users of tobacco products had higher PAH urinary biomarker concentrations compared to never users, and concentrations differed by type and frequency of tobacco product use.

Carcinogen Biomarkers in the Urine of Electronic Cigarette Users and Implications for the Development of Bladder Cancer: A Systematic Review

“…Compared with never-user controls, e-cigarette users had significantly higher levels of both 3-hydroxyfluorene [27] and 1-hydroxypyrene present in their urine [27,28]. These carcinogens are metabolites of fluorene and pyrene, respectively, and portend an increased risk of bladder cancer [27]. Similarly, both o-toluidine and 2-naphthylamine, which are known to produce bladder cancer in human and animal studies, were found in urine at 2.3-and 1.3-fold higher levels, respectively, than in non-e-cigarette user controls [12].…”

“…Similarly, both o-toluidine and 2-naphthylamine, which are known to produce bladder cancer in human and animal studies, were found in urine at 2.3-and 1.3-fold higher levels, respectively, than in non-e-cigarette user controls [12]. Thus, e-cigarette users can have urinary biomarker concentrations of several carcinogenic compounds, which are linked to bladder cancer, above the background levels that were found in the samples of nonuser controls [1,12,27,28] Very low levels of such carcinogenic compounds are usually found in human urine samples resulting from environmental or endogenous (eg, food) exposure [6,22,44]. These data suggest that although environmental and endogenous sources may contribute to some of the carcinogenic urinary biomarker levels detected, e-cigarette use extends these levels beyond the background levels of environmental exposures.…”

“…It is well established that aromatic amines and PAHs are carcinogenic to the human bladder [42]. These compounds have been identified as components of e-cigarette aerosols [6,43], and the presence of these biomarkers has been confirmed in the urine of e-cigarette users [12,27]. Compared with never-user controls, e-cigarette users had significantly higher levels of both 3-hydroxyfluorene [27] and 1-hydroxypyrene present in their urine [27,28].…”

“…Of the 22 included studies, four were randomized controlled trials [9,[23][24][25], six were multi-institutional studies [8,[24][25][26], 10 were single-institutional studies, two analyses were of the US Population Assessment of Tobacco and Health [27,28], and one was an analysis of the National Health and Nutrition Examination Survey [29]. In addition, two pairs of studies reported results from common datasets [7,9,23,30] and four were sponsored by the tobacco or ecigarette industry [9,23,25,31].…”

“…included a nonuser control group [1,12,[27][28][29]34], only a single study objectively confirmed a lack of combustible, ecigarette, or nicotine use through urine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNAL) and salivary cotinine testing [1]. Five studies confirmed absence of noncombustible tobacco use by carbon monoxide levels (<10 ppm) in expired breath [7,8,24,26,35].…”