Total Nicotine Equivalents Research Articles

Gender differences in the relationship between nicotine exposure and symptoms of depression

BackgroundTobacco-derived nicotine exposure is linked to depression. However, the associations of nicotine and its metabolites with symptoms of depression, particularly concerning gender differences, remain underexplored. MethodsThe characteristics and total nicotine equivalents (TNE) of 1001 subjects were determined. The association between the TNE and symptoms of depression, accounting for gender differences, was investigated using generalized linear models and subgroup analyses. ResultsMen exhibited significantly greater levels of the nicotine exposure indicators TNE2, TNE3, TNE6, and TNE7 (P < 0.005). A significantly greater percentage of women (23.45 %) than men (9.81 %) exhibited symptoms of depression (P < 0.0001). In women, the relationship between the TNE and depression was reflected by a U-shaped curve with significant inflection points, particularly for TNE3, TNE6, and TNE7. Furthermore, in women, concentrations above 48.98 nmol/mL for TNE3, 53.70 nmol/mL for TNE6, and 57.54 nmol/mL for TNE7 were associated with 154 %, 145 %, and 138 % increases in the risk of depression, respectively. In contrast, these associations did not reach significance among men. LimitationsThe cross-sectional design limits the ability to infer causality between nicotine exposure and depressive symptoms. Larger-scale studies are needed to confirm these findings. ConclusionsGender could be a significant factor influencing the relationship between nicotine exposure levels and symptoms of depression. The impact of nicotine exposure on symptoms of depression should be particularly considered among women. ImplicationsThis study revealed the complex relationship between tobacco-related nicotine exposure and depressive symptoms, with a particular focus on gender differences. Our results revealed a distinct U-shaped correlation between total nicotine equivalents and depression in women, which differed from that in men. These findings emphasize the importance of tailoring clinical approaches to address nicotine exposure and manage depressive symptoms based on gender.

Association of Urinary Biomarkers of Tobacco Exposure with Lung Cancer Risk in African American and White Cigarette Smokers in the Southern Community Cohort Study.

After accounting for smoking history, lung cancer incidence is greater in African Americans than Whites. In the multiethnic cohort, total nicotine equivalents (TNE) are higher in African Americans than Whites at similar reported cigarettes per day. Greater toxicant uptake per cigarette may contribute to the greater lung cancer risk of African Americans. In a nested case-control lung cancer study within the Southern Community Cohort, smoking-related biomarkers were measured in 259 cases and 503 controls (40% White; 56% African American). TNE, the trans-3-hydroxycotinine/cotinine ratio, 4-(methylnitrosamino)-1-3-(pyridyl)-1-butanol (NNAL), mercapturic acid metabolites of volatile organic compounds, phenanthrene metabolites, cadmium (Cd), and (Z)-7-(1R,2R,3R,5S)-3,5-dihydroxy-2-[(E,3S)-3-hydroxyoct-1-enyl]cyclopenyl]hept-5-enoic acid were quantified in urine. Unconditional logistic regression was used to estimate the ORs and 95% confidence intervals (CI) for each biomarker and lung cancer risk. TNE, NNAL, and Cd were higher in cases than controls (adjusted for age, race, sex, body mass index, and cigarettes per day). Among cases, these levels were higher in African Americans compared with Whites. After accounting for age, sex, body mass index, and pack-years, a one-SD increase in log-TNE (OR = 1.30; 95% CI, 1.10-1.54) and log-NNAL (OR = 1.27; 95% CI, 1.03-1.58 with TNE adjustment) was associated with lung cancer risk. In this study, in which NNAL concentration is relatively high, the association for log-TNE was attenuated after adjustment for log-NNAL. Smoking-related biomarkers provide additional information for lung cancer risk in smokers beyond smoking pack-years. Urinary NNAL, TNE, and Cd concentrations in current smokers, particularly African American smokers, may be useful for predicting lung cancer risk.

Assessing the Relationship between Biomarkers of Exposure and Biomarkers of Potential Harm: PATH Study Wave 1 (2013 to 2014).

The adequacy of biomarkers of potential harm (BOPH) for assessing tobacco products was explored based on their ability to distinguish tobacco use from non-use, change with cessation, and to show biological gradient. The sample included individuals with biomarker data in wave 1 of the Population Assessment of Tobacco Health study who never used tobacco, currently smoke cigarettes exclusively, used to smoke cigarettes exclusively (quit in past 12 months), currently use smokeless tobacco exclusively, and currently use e-cigarettes exclusively. We compared BOPH levels between groups and assessed the relationships between log-transformed biomarkers of exposure [BOE; total nicotine equivalents including seven nicotine metabolites (TNE-7), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanonol (NNAL), N-acetyl-S-(2-cyanoethyl)-L-cysteine, 1-hydroxypyrene, cadmium, and serum cotinine (SCOT)], and BOPH [high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), fibrinogen, soluble intercellular adhesion molecule-1 (sICAM-1), and 8-isoprostane]. Among people who smoke, both sICAM-1 and 8-isoprostane distinguished smoking from non-use and were associated with all six BOE. Among people who use smokeless tobacco, 8-isoprostane was associated with TNE-7 and NNAL whereas hs-CRP was associated with SCOT. Among people who use e-cigarettes, no associations between BOPH and BOE were observed. Both sICAM-1 and 8-isoprostane may be useful for assessing the use or changes in use of some tobacco products. Studies examining their predictive validity could further strengthen our understanding of these two biomarkers. We found that two biomarkers of potential harm, soluble intercellular adhesion molecule-1 and 8-isoprostane, may have utility in studies assessing the potential harm of tobacco use in absence of long-term epidemiological studies.

Abstract 1015: Potential of kava in reducing lung cancer risk and associated disparities: Mechanism-based biomarker discovery and analysis

Abstract Background: Lung cancer is the leading cause of cancer-related deaths. Tobacco smoke is well-recognized as the dominant risk factor. Stress, lung inflammation, air pollution and other factors also contribute to the risk of developing lung cancer Racial/ethnic disparities in lung cancer risks exit as well. The quantitative contributions of different these risk factors to lung cancer and associated disparities, however, have not been systematically characterized. One major barrier is the lack of tools to non-invasively and objectively quantify these risk factors, which precludes the identification of high-risk individuals and the development of effective prevention. Data from our group, particularly results from a pilot clinical trial, suggest that kava, traditionally consumed in the South Pacific Islands as a beverage to reduce stress and promote relaxation, may holistically reduce lung cancer risk by impacting multiple factors that contribute to lung cancer risk. Aim: This study aims to discover mechanism-based non-invasive biomarkers reflective of different lung cancer risk factors and explore their potential roles in lung cancer risk disparities. Such biomarkers are also employed to characterize the holistic effects of kava in reducing lung cancer risk and its potential in mitigating associated disparities. Results and Analysis: One-week of kava significantly reduced the level of nicotine exposure among smokers, quantified by the Total Nicotine Equivalents (TNE) in the 24-h urine sample. Excitingly the reduction in TNE appeared to be higher among African American smokers in comparison to participants of other race/ethnicity. Biomarkers for stress (plasma cortisol and urinary total cortisol equivalents (TCE)) were significantly reduced upon one-week kava use, which may mechanistically contribute to the reductions in tobacco use. The reduction in plasma cortisol and TCE were higher among African American smokers as well. One-week kava exposure also increased urinary excretion of total NNAL and reduced urinary 3-methyladenine (3-mA) in participants, suggestive of its ability to reduce the carcinogenicity of nicotine-derived nitrosamine ketone (NNK). Kava effects on NNAL and 3mA were again more pronounced among African American smokers. Conclusion and future directions: These results demonstrate the potential of mechanism-based biomarkers in investigating lung cancer risks and associated disparities. Such biomarkers may also facilitate the translational development of effective and targeted interventions, such as kava, which may not only reduce lung cancer risk but also mitigate the associated disparities. Additional mechanism-based biomarkers on other tobacco carcinogens and inflammation are currently under development. Two clinical trials are ongoing that the current clinical samples will help validate these discoveries. Citation Format: Chengguo Xing, Breanne Freeman, Jessica Mamallapalli, Allison Lynch, Naomi Fujioka, Ramzi G. Salloum, John Malaty, Frank Orlando, Zhiguang Huo. Potential of kava in reducing lung cancer risk and associated disparities: Mechanism-based biomarker discovery and analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1015.

Epigenome-wide association study of total nicotine equivalents in multiethnic current smokers from three prospective cohorts

The impact of tobacco exposure on health varies by race and ethnicity and is closely tied to internal nicotine dose, a marker of carcinogen uptake. DNA methylation is strongly responsive to smoking status and may mediate health effects, but study of associations with internal dose is limited. We performed a blood leukocyte epigenome-wide association study (EWAS) of urinary total nicotine equivalents (TNEs; a measure of nicotine uptake) and DNA methylation measured using the MethylationEPIC v1.0 BeadChip (EPIC) in six racial and ethnic groups across three cohort studies. In the Multiethnic Cohort Study (discovery, n= 1994), TNEs were associated with differential methylation at 408 CpG sites across >250 genomic regions (p<9×10-8). The top significant sites were annotated to AHRR, F2RL3, RARA, GPR15, PRSS23, and 2q37.1, all of which had decreasing methylation with increasing TNEs. We identified 45 novel CpG sites, of which 42 were unique to the EPIC array and eight annotated to genes not previously linked with smoking-related DNA methylation. The most significant signal in a novel gene was cg03748458 in MIR383;SGCZ. Fifty-one of the 408 discovery sites were validated in the Singapore Chinese Health Study (n= 340) and the Southern Community Cohort Study (n= 394) (Bonferroni corrected p<1.23×10-4). Significant heterogeneity by race and ethnicity was detected for CpG sites in MYO1G and CYTH1. Furthermore, TNEs significantly mediated the association between cigarettes per day and DNA methylation at 15 sites (average 22.5%-44.3% proportion mediated). Our multiethnic study highlights the transethnic and ethnic-specific methylation associations with internal nicotine dose, a strong predictor of smoking-related morbidities.

Association of Urinary N7-(1-hydroxyl-3-buten-1-yl) Guanine (EB-GII) Adducts and Butadiene-Mercapturic Acids with Lung Cancer Development in Cigarette Smokers.

Approximately 10% of smokers will develop lung cancer. Sensitive predictive biomarkers are needed to identify susceptible individuals. 1,3-Butadiene (BD) is among the most abundant tobacco smoke carcinogens. BD is metabolically activated to 3,4-epoxy-1-butene (EB), which is detoxified via the glutathione conjugation/mercapturic acid pathway to form monohydroxybutenyl mercapturic acid (MHBMA) and dihydroxybutyl mercapturic acid (DHBMA). Alternatively, EB can react with guanine nucleobases of DNA to form N7-(1-hydroxyl-3-buten-1-yl) guanine (EB-GII) adducts. We employed isotope dilution LC/ESI-HRMS/MS methodologies to quantify MHBMA, DHBMA, and EB-GII in urine of smokers who developed lung cancer (N = 260) and matched smoking controls (N = 259) from the Southern Community Cohort (white and African American). The concentrations of all three biomarkers were significantly higher in smokers that subsequently developed lung cancer as compared to matched smoker controls after adjusting for age, sex, and race/ethnicity (p < 0.0001 for EB-GII, p < 0.0001 for MHBMA, and p = 0.0007 for DHBMA). The odds ratio (OR) for lung cancer development was 1.63 for MHBMA, 1.37 for DHBMA, and 1.97 for EB-GII, with a higher OR in African American subjects than in whites. The association of urinary EB-GII, MHBMA, and DHBMA with lung cancer status did not remain upon adjustment for total nicotine equivalents. These findings reveal that urinary MHBMA, DHBMA, and EB-GII are directly correlated with the BD dose delivered via smoking and are associated with lung cancer risk.

Simultaneous Measurement and Distribution Analysis of Urinary Nicotine, Cotinine, Trans-3′-Hydroxycotinine, Nornicotine, Anabasine, and Total Nicotine Equivalents in a Large Korean Population

Measurement of multiple nicotine metabolites and total nicotine equivalents (TNE) might be a more reliable strategy for tobacco exposure verification than measuring single urinary cotinine alone. We simultaneously measured nicotine, cotinine, 3-OH cotinine, nornicotine, and anabasine using 19,874 urine samples collected from the Korean National Health and Nutrition Examination Survey. Of all samples, 18.6% were positive for cotinine, 17.4% for nicotine, 17.3% for nornicotine, 17.6% for 3-OH cotinine, and 13.2% for anabasine. Of the cotinine negative samples, less than 0.3% were positive for all nicotine metabolites, but not for anabasine (5.7%). The agreement of the classification of smoking status by cotinine combined with nicotine metabolites was 0.982–0.994 (Cohen’s kappa). TNE3 (the molar sum of urinary nicotine, cotinine, and 3-OH cotinine) was most strongly correlated with cotinine compared to the other nicotine metabolites; however, anabasine was less strongly correlated with other biomarkers. Among anabasine-positive samples, 30% were negative for nicotine or its metabolites, and 25% were undetectable. Our study shows that the single measurement of urinary cotinine is simple and has a comparable classification of smoking status to differentiate between current smokers and non-smokers relative to the measurement of multiple nicotine metabolites. However, measurement of multiple nicotine metabolites and TNE3 could be useful for monitoring exposure to low-level or secondhand smoke exposure and for determining individual differences in nicotine metabolism. Geometric or cultural factors should be considered for the differentiation of tobacco use from patients with nicotine replacement therapy by anabasine.

"Titrating Tobacco Treatment Medications Using Total Nicotine Equivalents and Expired Breath Carbon Monoxide: A Path to Increasing Quit Rates and Medical Revenues"

"Titrating Tobacco Treatment Medications Using Total Nicotine Equivalents and Expired Breath Carbon Monoxide: A Path to Increasing Quit Rates and Medical Revenues"

Epigenome-wide association study of urinary total nicotine equivalents in multiethnic current smokers from three prospective cohorts

Epigenome-wide association study of urinary total nicotine equivalents in multiethnic current smokers from three prospective cohorts

Nicotine Intake in Adult Pod E-cigarette Users: Impact of User and Device Characteristics.

This study examined user behavior, e-cigarette dependence, and device characteristics on nicotine intake among users of pod-mod e-cigarettes. In 2019-2020, people who use pod-mods in the San Francisco Bay Area completed questionnaires and provided a urine sample for analysis of total nicotine equivalents (TNE). The relationship between TNE and e-cigarette use, e-cigarette brands, e-liquid nicotine strength, e-cigarette dependence, and urine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), as a measure of combustible cigarette exposure, were examined. Of 100 participants (64% male, 71% in the 18-34 age group, 45% white), 53 used JUUL primarily, 12 used Puff Bar primarily, and 35 used other brands, including Suorin; 48 participants reported current cigarette smoking. Participants most often reported use of e-liquid with 4.5%-6.0% nicotine (68%), fruit (35%), tobacco (28%), and menthol or mint flavors (26%), used e-cigarettes on 25.5 (SD = 6.3) days a month, 10.2 (SD = 14.2) times a day, and 40% used 1-2 pods/cartridges per week. In bivariate analysis, urinary TNE was higher with greater frequency (days used) and intensity (number of pods used) of e-cigarette use, e-cigarette dependence, and combustible cigarette use. In multivariable analysis, days of e-cigarette use in the last 30 days, number of pods used per week, and NNAL levels were significantly associated with TNE. There was no significant impact of e-liquid nicotine strength on TNE. Nicotine intake among people who used pod-mod e-cigarettes increased with e-cigarette consumption and e-cigarette dependence, but not with e-liquid nicotine strength. Our findings may inform whether FDA adopts a nicotine standard for e-cigarettes. The study examined how device and user characteristics influence nicotine intake among pod-mod e-cigarette users. Nicotine intake increased with frequency (days of e-cigarette use in past 30 days) intensity of use (number of pods used per day) and e-cigarette dependence but not with the flavor or nicotine concentration of the e-liquids. Regulation of nicotine concentration of e-liquids is unlikely to influence nicotine exposure among adult experienced pod-mod users.

Validation of Urinary Thiocyanate as a Robust Biomarker of Active Tobacco Smoking in the Prospective Urban and Rural Epidemiological Study.

Tobacco smoking is a leading preventable cause of premature death globally. Urinary thiocyanate is a biomarker of cyanide exposure from tobacco smoke; however, few studies have evaluated its utility in diverse populations of smokers. We examined the associations between urinary thiocyanate and self-reported never and current smokers among 1000 participants from 14 countries in the Prospective Urban and Rural Epidemiological study. We analyzed urinary thiocyanate in light and heavy smokers as compared to never-smokers from high- (HICs), middle- (MICs), and low-income countries (LICs) using a validated capillary electrophoresis method in conjunction with standardized questionnaires. The median urinary thiocyanate concentration was 31 μM, which ranged from 8.6 μM to 52 μM for never-smokers (n = 335) and current smokers (n = 660), respectively. Urinary thiocyanate was correlated with daily cigarette consumption (r = 0.621) and total nicotine equivalents (r = 0.514). Thiocyanate also displayed a better dose-response than urinary cotinine. A moderate association of urinary thiocyanate was found in biochemically verified never-smokers (r ~0.38) because of intake of vegetables, fruits, and dairy. Receiver-operating characteristic curves established cutoff values for urinary thiocyanate to differentiate current from never-smokers with an optimal threshold of 23.9 μM (Area Under the Curve or AUC = 0.861), which lowered progressively from HICs, MICs, and LICs. Elevated thiocyanate was evident in current smokers from high-income countries likely reflecting differences in smoking topography and greater toxicant burden. Background urinary thiocyanate in never-smokers was associated with goitrogenic food intake that obscured detection of secondhand smoke exposure. Urinary thiocyanate is a sensitive biomarker of active tobacco smoking relative to cotinine that can be measured by an inexpensive capillary electrophoresis assay. Regional cutoff values are demonstrated to improve discrimination of smoking status in developing countries because of differences in smoking habits and cigarette products consumed, as well as intake of goitrogenic foods. Urinary thiocyanate may allow for more reliable estimates of the hazards of tobacco smoking between countries with varying socioeconomic development as compared to self-reports.

Association of Urinary Biomarkers of Smoking-Related Toxicants with Lung Cancer Incidence in Smokers: The Multiethnic Cohort Study.

While cigarette smoking is the leading cause of lung cancer, the majority of smokers do not develop the disease over their lifetime. The inter-individual differences in risk among smokers may in part be due to variations in exposure to smoking-related toxicants. Using data from a subcohort of 2,309 current smokers at the time of urine collection from the Multiethnic Cohort Study, we prospectively evaluated the association of ten urinary biomarkers of smoking-related toxicants [total nicotine equivalents (TNE), a ratio of total trans-3'-hydroxycotinine (3-HCOT)/cotinine (a phenotypic measure of CYP2A6 enzymatic activity), 4-(methylnitrosamino)-1-3-(pyridyl)-1-butanol (NNAL), S-phenylmercapturic acid (SPMA), 3-hydroxypropyl mercapturic acid (3-HPMA), phenanthrene tetraol (PheT), 3-hydroxyphenanthrene (PheOH), the ratio of PheT/PheOH, cadmium (Cd), and (Z)-7-(1R,2R,3R,5S)-3,5-dihydroxy-2-[(E,3S)-3-hydroxyoct-1-enyl]cyclopenyl]hept-5-enoic acid (8-iso-PGF2α)] with lung cancer risk (n = 140 incident lung cancer cases over an average of 13.4 years of follow-up). Lung cancer risk was estimated using Cox proportional hazards models. After adjusting for decade of birth, sex, race/ethnicity, body mass index, self-reported pack-years, creatinine, and urinary TNE (a biomarker of internal smoking dose), a one SD increase in log total 3-HCOT/cotinine (HR, 1.33; 95% CI, 1.06-1.66), 3-HPMA (HR, 1.41; 95% CI, 1.07-1.85), and Cd (HR, 1.45; 95% CI, 1.18-1.79) were each associated with increased lung cancer risk. Our study demonstrates that urinary total 3-HCOT/cotinine, 3-HPMA, and Cd are positively associated with lung cancer risk. These findings warrant replication and consideration as potential biomarkers for smoking-related lung cancer risk. These biomarkers may provide additional information on lung cancer risk that is not captured by self-reported smoking history or TNE. See related commentary by Etemadi et al., p. 289.

Immediate Switching to Reduced Nicotine Cigarettes in a U.S.-Based Sample: The Impact on Cannabis Use and Related Variables at 20 Weeks.

The FDA proposed rule-making to reduce nicotine in cigarettes to minimally addictive levels. Research suggests decreasing nicotine levels (i.e. very low nicotine content cigarettes [VLNCs]) produced greater quit attempts, reduced smoking, and reduced exposure to harmful constituents among smokers. The impact of long-term VLNC use among people who co-use cigarettes and cannabis on non-tobacco-specific toxicant and carcinogen exposure has not been investigated. This study presents secondary analyses of a controlled clinical trial examining switching to VLNC (versus a normal nicotine cigarettes control group [NNCs]) between people who co-use cigarettes and cannabis (n = 174) versus smoked cigarettes (n = 555). Linear mixed-effects models compared changes in smoking behavior, and tobacco-specific (i.e. total nicotine equivalents [TNE], 4-[methylnitrosamino]-1-[3-pyridyl]-1-butanone [NNK; total NNAL]) and non-tobacco-specific (i.e. carbon monoxide (CO), 2-cyanoethylmercapturic acid [CEMA], phenanthrene tetraol [PheT]) toxicant and carcinogen exposure at week 20 (with random intercept for participants). Cannabis use was measured among co-use groups. CO was significantly lower only among the cigarette-only group assigned VLNCs (interaction: p = .015). Although both VLNC groups demonstrated decreased CEMA, greater decreases emerged among the cigarette-only group (interaction: p = .016). No significant interactions emerged for TNE, cigarettes per day (CPD), NNAL, and PheT (ps > .05); both VLNC groups decreased in TNE, CPD, and NNAL. Only the cigarette-only group assigned VLNCs demonstrated decreased PheT (p < .001). The VLNC co-use group showed increased cannabis use over time (p = .012; 0.5 more days per week by week 20). Those who co-use cannabis and cigarettes may still be at risk for greater exposure to non-tobacco-specific toxicants and carcinogens compared to those who only smoke cigarettes. The present study is the longest longitudinal, prospective comparison study of smoking behavior and exposure to harmful constituents among those who co-use cigarettes and cannabis versus cigarette-only after immediately switching to very low nicotine content cigarettes (VLNC). Those who co-use experienced similar reductions in CPD and tobacco-specific exposure, compared to those who only use cigarettes. However, co-use groups experienced smaller reductions in non-tobacco-specific toxicants and carcinogens compared to the cigarette-only group, potentially because of combustible cannabis use. Additionally, those who co-use and switched to VLNC may be susceptible to slight increases in cannabis use (approximately two more days per year).

THE CHEST TOBACCO TREATMENT TOOLKIT: CHRONIC DISEASE MANAGEMENT, POINT-OF-CARE BIOCHEMISTRY ASSAYS, AND TITRATION OF TOBACCO TREATMENT MEDICATIONS INCREASES QUIT RATES

THE CHEST TOBACCO TREATMENT TOOLKIT: CHRONIC DISEASE MANAGEMENT, POINT-OF-CARE BIOCHEMISTRY ASSAYS, AND TITRATION OF TOBACCO TREATMENT MEDICATIONS INCREASES QUIT RATES

Increased Levels of the Acrolein Metabolite 3-Hydroxypropyl Mercapturic Acid in the Urine of e-Cigarette Users.

Carcinogen and toxicant uptake by e-cigarette users have not been fully evaluated. In the study reported here, we recruited 30 e-cigarette users, 63 nonsmokers, and 33 cigarette smokers who gave monthly urine samples over a period of 4-6 months. Their product use status was confirmed by measurements of exhaled CO, urinary total nicotine equivalents, cyanoethyl mercapturic acid (CEMA), and total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol. Urinary biomarkers of exposure to the carcinogens acrolein (3-hydroxypropyl mercapturic acid, 3-HPMA), benzene (S-phenyl mercapturic acid, SPMA), acrylonitrile (CEMA), and a combination of crotonaldehyde, methyl vinyl ketone, and methacrolein (3-hydroxy-1-methylpropyl mercapturic acid, HMPMA) were quantified at each visit. Data from subject visits with CEMA > 27 pmol/mL were excluded from the statistical analysis of the results because of possible unreported exposures to volatile combustion products such as secondhand cigarette smoke or marijuana smoke exposure; this left 22 e-cigarette users with 4 or more monthly visits and all 63 nonsmokers. Geometric mean levels of 3-HPMA (1249 versus 679.3 pmol/mL urine) were significantly higher (P = 0.003) in e-cigarette users than in nonsmokers, whereas levels of SPMA, CEMA, and HMPMA did not differ between these two groups. All analytes were significantly higher in cigarette smokers than in either e-cigarette users or nonsmokers. The results of this unique multimonth longitudinal study demonstrate consistent significantly higher uptake of the carcinogen acrolein in e-cigarette users versus nonsmokers, presenting a warning signal regarding e-cigarette use.

Abstract 5705: Identifying DNA methylation quantitative trait loci across multi-ethnic populations

Abstract Objective: To date, genome-wide association studies (GWAS), which are primarily conducted in Europeans, have identified a large number of validated DNA methylation quantitative trait loci (meQTLs) acting in both cis and trans. However, it is recognized that there are racial differences in genetic architectures such as allele frequencies and linkage equilibrium patterns, which may differentially influence DNA methylation levels. This points to a critical need to conduct a methylome wide association study (MWAS) to identify meQTLs across multiethnic populations including understudied African Americans (AAs), Latinos, Japanese Americans (JAs), and Native Hawaiians (NHs). Methods: We are performing a GWAS to identify meQTLs in blood leukocytes in a multiethnic population using data from the Multiethnic Cohort Study (MEC). In MEC, “genome-wide” germline genetic variants and DNA methylation levels of blood leukocytes have been measured using the Illumina 1M and MethEPIC array, respectively, for 372 AAs, 408 Latinos, 531 JAs, 319 NHs, and 406 European Americans who were current smokers at time of blood draw. Genotyped data has been imputed with 1000 Genomes phase 3 dataset. For DNA methylation data, standardized quality control (QC) and normalization have been performed. We adjusted for the following potential confounders at time of blood draw: age, sex, body mass index, estimated cell type composition variables, genetic principal components, smoking pack-years, and urinary total nicotine equivalents (a biomarker for internal smoking dose). A stringent Bonferroni-corrected threshold (P&amp;lt;5×10-8/(850,355×6) = 9.80×10-15) was used to define statistical significance. An independent dataset of MEC participants including 114 AAs, 142 Latinos, 286 JAs, 108 NHs, and 270 European Americans will be used to replicate the identified meQTLs. Results: Our preliminary analyses for identifying cis-meQTL SNPs (residing within 1 Mb upstream or downstream of a CpG site of interest) found 169,823 CpG sites (20.0%) are associated with at least one nearby genetic variant in AAs. Similarly, 284,371 CpG sites (33.4%) in JAs, 168,580 CpG sites (19.8%) in Latinos, 123,032 CpG sites (14.5%) in NHs, and 234,822 CpG sites (27.6%) in European Americans are significantly associated with at least one nearby genetic variant. In the pan-ethnic analyses including all five ethnic/racial groups, 193,743 CpG sites (23.0%) are associated with at least one nearby genetic variant. Conclusion: Our preliminary findings identified ethnic-specific and pan-ethnic cis-meQTL SNPs across a multiethnic population that includes understudied AAs, Latinos, JAs, NHs, along with European Americans. If replicated in independent datasets, these findings will significantly improve our understanding of genetic regulation of DNA methylation levels in these populations. Citation Format: Lang Wu, Xiequn Xu, Dalia Ghoneim, Kayla Kim, Alexandra Binder, Yesha Patel, Daniel O. Stram, Loïc Le Marchand, Sungshim L. Park. Identifying DNA methylation quantitative trait loci across multi-ethnic populations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5705.

Exploring Potential for a Personalized Medicine Approach to Smoking Cessation With an American Indian Tribe.

A potential precision medicine approach to smoking cessation is tailoring pharmacotherapy to a biomarker known as the nicotine metabolite ratio (NMR). Little is known about the potential impact and acceptability of this approach for American Indian (AI) persons. Tribal-academic collaboration was formed and during 2019-2020 AI adults who smoke(N = 54) were recruited to (1) examine correlations between NMR, dependence, and smoking exposure; (2) assess the extent to which pharmacotherapy preference aligned with NMR-informed recommendations; (3) explore acceptability of NMR-informed pharmacotherapy selection. Participants provided samples for assessment of salivary NMR and urinary total nicotine equivalents (TNE) and completed a questionnaire that assessed cigarettes per day (CPD), Fagerstrom Test for Cigarette Dependence (FTCD), pharmacotherapy preference, and perceptions of NMR-informed pharmacotherapy selection. Significant positive correlations were observed between NMR and FTCD (r = 0.29;p = .0383) and its abbreviated version Heaviness of Smoking Index (HIS) (r = 0.28;p =.0426). Post-hoc analyses suggest that relationships between dependence and NMR were driven by time to first cigarette. Nonsignificant, but directionally consistent, relationships were observed between NMR and CPD (r = 0.21; p =0.1436) and TNE (r = 0.24;p = .2906). Most participants preferred nicotine replacement therapy (71%) over varenicline (29%) and preference for pharmacotherapy matched NMR-based recommendations in 54% of participants. NMR-informed pharmacotherapy selection was supported by 62% of participants. In a sample of AI adults who smoke, NMR was related to cigarette dependence and about one-half of participants' pharmacotherapy preference matched their NMR-informed recommendation. There was lower acceptability of NMR-informed approach in this sample of AI adults than prior studies among white or black/African American people who smoke. Relationships between NMR, dependence, and self-preference for pharmacotherapy suggest that NMR-informed pharmacotherapy selection may have potential for enhancing smoking quitting success in this Tribe. Lower acceptability of NMR-informed pharmacotherapy in this Tribe suggests that this approach may not be equitably utilized. Future work could include identifying community-driven solutions to mitigate precision medicine concerns.

Variability in Urinary Nicotine Exposure Biomarker Levels Between Waves 1 (2013-2014) and 2 (2014-2015) in the Population Assessment of Tobacco and Health Study.

To date, no studies have evaluated the consistency of biomarker levels in people who smoke over a long-time period in real-world conditions with a large number of subjects and included use behavior and measures of nicotine metabolism. We evaluated the variability of biomarkers of nicotine exposure over approximately a 1-year period in people who exclusively smoke cigarettes, including intensity and recency of use and brand switching to assess impact on understanding associations with product characteristics. Multivariate regression analysis of longitudinal repeated measures of urinary biomarkers of nicotine exposure from 916 adults in the Population Assessment of Tobacco and Health (PATH) Study with demographic characteristics and use behavior variables. Intraclass correlation coefficients (ICCs) were calculated to examine individual variation of nicotine biomarkers and the uncertainty of repeat measures at two time points (Waves 1 and 2). Age, race, and urinary creatinine were significant covariates of urinary cotinine. When including use behavior, recency, and intensity of use were highly significant and variance decreased to a higher extent between than within subjects. The ICC for urinary cotinine decreased from 0.7530 with no use behavior variables in the model to 0.5763 when included. Similar results were found for total nicotine equivalents. Urinary nicotine biomarkers in the PATH Study showed good consistency between Waves 1 and 2. Use behavior measures such as time since last smoked a cigarette and number of cigarettes smoked in the past 30 days are important to include when assessing factors that may influence biomarker concentrations. The results of this study show that the consistency of the nicotine biomarkers cotinine and total nicotine equivalents in spot urine samples from Waves 1 to 2 of the PATH Study is high enough that these data are useful to evaluate the association of cigarette characteristics with biomarkers of exposure under real-world use conditions.

Nicotine Exposure in the U.S. Population: Total Urinary Nicotine Biomarkers in NHANES 2015-2016.

We characterize nicotine exposure in the U.S. population by measuring urinary nicotine and its major (cotinine, trans-3′-hydroxycotinine) and minor (nicotine 1′-oxide, cotinine N-oxide, and 1-(3-pyridyl)-1-butanol-4-carboxylic acid, nornicotine) metabolites in participants from the 2015–2016 National Health and Nutrition Examination Survey. This is one of the first U.S. population-based urinary nicotine biomarker reports using the derived total nicotine equivalents (i.e., TNEs) to characterize exposure. Serum cotinine data is used to stratify tobacco non-users with no detectable serum cotinine (−sCOT), non-users with detectable serum cotinine (+sCOT), and individuals who use tobacco (users). The molar concentration sum of cotinine and trans-3′-hydroxycotinine was calculated to derive the TNE2 for non-users. Additionally, for users, the molar concentration sum of nicotine and TNE2 was calculated to derive the TNE3, and the molar concentration sum of the minor metabolites and TNE3 was calculated to derive the TNE7. Sample-weighted summary statistics are reported. We also generated multiple linear regression models to analyze the association between biomarker concentrations and tobacco use status, after adjusting for select demographic factors. We found TNE7 is positively correlated with TNE3 and TNE2 (r = 0.99 and 0.98, respectively), and TNE3 is positively correlated with TNE2 (r = 0.98). The mean TNE2 concentration was elevated for the +sCOT compared with the −sCOT group (0.0143 [0.0120, 0.0172] µmol/g creatinine and 0.00188 [0.00172, 0.00205] µmol/g creatinine, respectively), and highest among users (33.5 [29.6, 37.9] µmol/g creatinine). Non-daily tobacco use was associated with 50% lower TNE7 concentrations (p < 0.0001) compared with daily use. In this report, we show tobacco use frequency and passive exposure to nicotine are important sources of nicotine exposure. Furthermore, this report provides more information on non-users than a serum biomarker report, which underscores the value of urinary nicotine biomarkers in extending the range of trace-level exposures that can be characterized.

Increased acrolein-DNA adducts in buccal brushings of e-cigarette users.

DNA adducts are central in the mechanism of carcinogenesis by genotoxic agents. We compared levels of a DNA adduct of acrolein, a genotoxic carcinogen found in e-cigarette vapor, in oral cell DNA of e-cigarette users and non-users of any tobacco or nicotine product. e-Cigarette users and non-users visited our clinic once monthly for 6 months, and oral brushings and urine samples were collected. For this study, we analyzed oral cell DNA adducts from three monthly visits in e-cigarette users and non-users as confirmed by urinary cyanoethyl mercapturic acid and total nicotine equivalents. DNA was isolated from the oral brushings and analyzed by a validated liquid chromatography-nanoelectrospray ionization-high resolution tandem mass spectrometry method for the acrolein DNA adduct 8R/S-3-(2'-deoxyribos-1'-yl)-5,6,7,8-tetrahydro-8-hydroxypyrimido[1,2-a]purine-10-(3H)-one (γ-OH-Acr-dGuo). The median value of this DNA adduct in the e-cigarette users was 179 fmol/µmol dGuo (range 5.0 - 793 fmol/µmol dGuo) while that for non-users was 21.0 fmol/µmol dGuo (range 5.0 - 539 fmol/µmol dGuo), P = 0.001. These results demonstrate for the first time that e-cigarette users have elevated levels of a carcinogen-DNA adduct in their oral cells.