Tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in smokers in the United States: NHANES 2007-2008

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

INTRODUCTION

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.

AIMS AND METHODS

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).

RESULTS

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.

CONCLUSIONS

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.

IMPLICATIONS

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.

Passive exposure to electronic cigarette aerosol in pregnancy: A case study of a family

BACKGROUND

Passive exposure to the aerosols of electronic cigarettes (e-cigarettes) has been little studied. We assessed this exposure in late pregnancy in a woman and her 3-year-old child, exposed through e-cigarette use by another household member.

METHODS

This prospective longitudinal case study involved a family unit consisting of an e-cigarette user, a pregnant woman who delivered an infant during the study, and the couple's older 3-year-old son. At 31, 36, and 40 weeks of the pregnancy, we measured biomarkers (nicotine metabolites, tobacco-specific nitrosamines, propanediols, glycerol, and metals) in the urine and hair of all three participants and in the saliva of the adults, in cord blood at delivery, and in the breast milk at the postpartum period.

RESULTS

Samples from the e-cigarette user showed quantifiable concentrations of all analytes assessed (maximum urinary cotinine concentration, 4.9 ng/mL). Among samples taken from the mother, nicotine and its metabolites were found mainly in urine and also in saliva and hair, but not in cord blood. During the postpartum period, we found cotinine concentrations of 2.2 ng/mL in the mother's urine and 0.22 ng/mL in breast milk; 1,2-propanediol was generally detected in urine and saliva, but not in cord blood or breast milk. The maximum urinary cotinine concentration in the 3-year-old child was 2.6 ng/mL and propanediols also were detected in his urine. Nitrosamines were not detected in samples taken from the mother or the 3-year-old. Metals found in the refill liquid were detected at low levels in both the mother and the 3-year-old.

CONCLUSIONS

We detected low but not negligible concentrations of e-cigarette-related analytes (including cord blood and breast milk) in an exposed pregnant non-user and in a 3-year-old child also living in the home. Passive exposure to e-cigarette aerosols cannot be disregarded and should be assessed in larger observational studies.

Smoke-Free Policies and 30-Day Mortality Rates for Chronic Obstructive Pulmonary Disease

BACKGROUND

Smoke-free policies have been shown to impact 30-day readmission rates due to chronic obstructive pulmonary disease (COPD) among adults aged ≥65 years. However, little is known about the association between smokefree policies and 30-day mortality rates for COPD. Therefore, we investigated the association between comprehensive smoke-free policies and 30-day mortality rates for COPD.

METHODS

We used a cross-sectional study design and retrospectively examined risk-adjusted 30-day mortality rates for COPD across US hospitals in 1171 counties. Data were sourced from Centers for Medicare and Medicaid Services (CMS) Hospital Value-Based Purchasing (HVBP) Program, American Hospital Association (AHA) Annual Surveys, US Census Bureau Current Population Survey, and US Tobacco Control Laws Database from the American Nonsmokers' Rights Foundation (ANRF). Data were averaged at the county level for years 2015-2018. Hierarchical Poisson models adjusted for differences in hospital characteristics and accounted for the clustering of hospitals within a county were used.

RESULTS

Our findings show a consistent association between stronger smoke-free policies and a reduction in COPD mortality. When evaluating smoke-free policy, county characteristics, and hospital characteristics individually, we found that counties with full coverage or partial coverage had a reduced incidence rate of COPD mortality compared to no coverage counties. After adjusting for the county and hospital characteristics, counties with full coverage of smoke-free policies had a reduced rate of 30-day COPD mortality (adjusted incidence rate ratio [IRR]: 0.87, 95% CI: 0.79, 0.96) compared to counties with no policy coverage.

CONCLUSION

Comprehensive smoke-free policies are associated with a reduction in 30-day mortality following hospital admission for COPD. Partial smoke-free legislation is an insufficient preventative measure. These findings have strong implications for hospital policy-makers, suggesting that policy interventions to reduce COPD-related 30-day mortality should include implementing smoke-free policies and public health policy-makers to incentivize comprehensive smokefree policies.

LKB1 phosphorylation and deactivation in lung cancer by NNAL, a metabolite of tobacco-specific carcinogen, in an isomer-dependent manner

LKB1 loss of function is one key oncogenic event in lung cancer. Clinical data suggest that LKB1 loss of function is associated with patients' smoking status. The responsible ingredients and molecular mechanisms in tobacco for LKB1 loss of function, however, are not defined. In this study, we reported that NNAL, a major metabolite of a tobacco-specific carcinogen NNK, induces LKB1 phosphorylation and its loss of function via the β-AR/PKA signaling pathway in an isomer-dependent manner in human lung cancer cells. NNAL exposure also resulted in enhanced lung cancer cell migration and chemoresistance in an LKB1-dependent manner. A 120-day NNAL exposure in lung cancer cells, mimicking its chronic exposure among smokers, resulted in more prominent LKB1 phosphorylation, cell migration, and chemoresistance even in the absence of NNAL, indicating the long-lasting LKB1 loss of function although such an effect eventually disappeared after NNAL was removed for two months. These observations were confirmed in a lung cancer xenograft model. More importantly, human lung cancer tissues revealed elevated LKB1 phosphorylation in comparison to the paired normal lung tissues. These results suggest that LKB1 loss of function in human lung cancer could be extended to its phosphorylation, which may be mediated by NNAL from tobacco smoke in an isomer-dependent manner via the β-AR/PKA signaling pathway.

Short-term smoking increases the risk of insulin resistance

Insulin resistance can be affected directly or indirectly by smoking. This cross-sectional study aimed at examining the association between smoking patterns and insulin resistance using objective biomarkers. Data from 4043 participants sourced from the Korea National Health and Nutrition Examination Survey, conducted from 2016 to 2018, were examined. Short-term smoking patterns were used to classify participants according to urine levels of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and cotinine as continuous-smokers, past-smokers, current-smokers, and non-smokers. Insulin resistance was calculated using the triglyceride-glucose index from blood samples and was defined as either high or low. Multiple logistic regression analysis was performed to investigate the association between smoking behavior and insulin resistance. Men and women who were continuous-smokers (men: odds ratio [OR] = 1.74, p = 0.001; women: OR = 2.01, p = 0.001) and past-smokers (men: OR = 1.47, p = 0.033; women: OR = 1.37, p = 0.050) were more likely to have high insulin resistance than their non-smoking counterparts. Long-term smokers (≥ 40 days) are at an increased risk of insulin resistance in short-term smoking patterns. Smoking cessation may protect against insulin resistance. Therefore, first-time smokers should be educated about the health benefits of quitting smoking.

Association between Second-hand Smoke Exposure and Urinary NNAL Level in Korean Adolescents

BACKGROUND

The 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) is a metabolite of tobacco-specific lung carcinogen that can be found in both smokers and non-smokers. Particularly, NNAL levels of children with a history of exposure to second-hand smoke (SHS) are higher than those of adults. Thus, we aimed to investigate the association between SHS exposure and urine NNAL levels in Korean adolescents.

METHODS

This cross-sectional study used data from the Korea National Health and Nutrition Examination Survey VII. Overall, 648 never-smoking adolescents (425 boys and 223 girls) aged 12 to 18 were included in this study. Logistic regression analyses identified the relationship between SHS exposure and elevated urine NNAL levels.

RESULTS

The mean urine NNAL levels of the no exposure and exposure group in boys were 1.39 and 2.26 ng/mL, respectively, whereas they were 1.01 and 2.45 ng/mL in girls, respectively (P < 0.001). Among the adolescents exposed to SHS, the confounder-adjusted odds ratio (95% confidence intervals) for elevated urine NNAL levels according to exposure area as overall, home, and public area were 2.68 (1.58-4.53), 31.02 (9.46-101.74), and 1.89 (1.12-3.17) in boys; and 6.50 (3.22-13.11), 20.09 (7.08-57.04), and 3.94 (1.98-7.77) in girls, respectively.

CONCLUSION

SHS exposure was significantly associated with elevated urine NNAL levels in Korean adolescents, particularly in female adolescents and in those with home exposure. These findings remind us of the need to protect adolescents from SHS.

Association of a Tobacco-specific Nitrosamine Carcinogen with Urinary Cotinine, Urinary Sodium Excretion, and Total Energy Intake in Adolescents and Children

This study investigated the association of a tobacco-specific nitrosamine carcinogen, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) with urinary cotinine (uCot), urinary sodium (uNa) excretion, systolic blood pressure (sBP), and total energy intake in adolescents and children in relation to the subjects' age. A total of 790 subjects aged 6-19 years were evaluated. NNAL, uCot, corrected NNAL (cNNAL), the NNAL/uCot ratio, uNa, sBP, and nutrient intake were measured. A strong association between uCot and cNNAL was observed in children who were 11 years of age (r=0.881, P<0.001); however, no significant association was noted in adolescents who were 19 years of age. The uNa level was significantly higher (133.9 mmol/L vs. 107.8 mmol/L, P<0.001) and sBP was significantly lower (105.3 mmHg vs. 110.6 mmHg, P=0.012) in adolescents with elevated NNAL than in those without elevated NNAL. NNAL was significantly higher in subjects with increased uNa excretion than in those without increased uNa excretion. NNAL was positively correlated with uNa (r=0.183, P<0.001) and negatively correlated with sBP (r=-0.142, P<0.001). Non-smokers with elevated NNAL/uCot ratios had significantly lower total energy intake than those without elevated NNAL/uCot ratios (1729.0 kcal/day vs. 1911.0 kcal/day, P=0.008). The relationship between NNAL and uCot varied according to the subjects' age. NNAL seems to play a role in decreasing sBP by enhancing uNa excretion. Insufficient nutrient intake may contribute to endogenous formation of NNAL in non-smoking adolescents and children.

Tobacco-Specific Nitrosamines (NNAL, NNN, NAT, and NAB) Exposures in the US Population Assessment of Tobacco and Health (PATH) Study Wave 1 (2013-2014)

INTRODUCTION

The tobacco-specific nitrosamines (TSNAs) are an important group of carcinogens found in tobacco and tobacco smoke. To describe and characterize the levels of TSNAs in the Population Assessment of Tobacco and Health (PATH) Study Wave 1 (2013-2014), we present four biomarkers of TSNA exposure: N'-nitrosonornicotine, N'-nitrosoanabasine, N'-nitrosoanatabine, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) which is the primary urinary metabolite of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone.

METHODS

We measured total TSNAs in 11 522 adults who provided urine using automated solid-phase extraction coupled to isotope dilution liquid chromatography-tandem mass spectrometry. After exclusions in this current analysis, we selected 11 004 NNAL results, 10 753 N'-nitrosonornicotine results, 10 919 N'-nitrosoanatabine results, and 10 996 N'-nitrosoanabasine results for data analysis. Geometric means and correlations were calculated using SAS and SUDAAN.

RESULTS

TSNA concentrations were associated with choice of tobacco product and frequency of use. Among established, every day, exclusive tobacco product users, the geometric mean urinary NNAL concentration was highest for smokeless tobacco users (993.3; 95% confidence interval [CI: 839.2, 1147.3] ng/g creatinine), followed by all types of combustible tobacco product users (285.4; 95% CI: [267.9, 303.0] ng/g creatinine), poly tobacco users (278.6; 95% CI: [254.9, 302.2] ng/g creatinine), and e-cigarette product users (6.3; 95% CI: [4.7, 7.9] ng/g creatinine). TSNA concentrations were higher in every day users than in intermittent users for all the tobacco product groups. Among single product users, exposure to TSNAs differed by sex, age, race/ethnicity, and education. Urinary TSNAs and nicotine metabolite biomarkers were also highly correlated.

CONCLUSIONS

We have provided PATH Study estimates of TSNA exposure among US adult users of a variety of tobacco products. These data can inform future tobacco product and human exposure evaluations and related regulatory activities.

Comparing cotinine and NNAL verification of self-reported smoking status among lung cancer screening eligible population from the 2007-2014 National Health and Nutrition Examination Survey (NHANES)

Background: Biochemical verification of self-reported smoking status is not common among the population eligible for lung cancer screening (LCS). Methods: We used urinary NNAL (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronides) and serum cotinine as the gold standard to determine the validity and reliability of self-reported smoking status from the 2007-2014 National Health and Nutrition Examination Survey (NHANES). Results: We found 2.3% (n = 652, equivalent to 5.3 million weighted population) of adults eligible for LCS according to the current United States Preventive Services Task Force guideline. Self-reported current smoking status performed similarly against NNAL and cotinine: sensitivity [89.7% (95%CI: 84.9%-94.5%) vs. 89.5% (95%CI: 84.8%-94.3%)]; specificity [99.7% (95%CI: 99.2%-100.0%) vs. 100% (95%CI:100%-100%)]; positive predictive value (PPV) and negative predictive value (NPV) were 99.8% (95%CI:99.4%-100.0%) versus 100% (95%CI:100%-100%) and 85.3% (95%CI: 79.1%-91.5%) versus 85.1% (95%CI: 79.1%-1.0%), respectively; and Kappa [86.5% (95%CI:80.5%-92.5%) vs. 86.5% (95%CI:80.6%-92.3%)]. Performance measures were better among females than males; worst among the non-Hispanic white and best among other race/ethnicity group. The validity and reliability of self-reported smoking status increased with increasing cutpoint levels of both NNAL and cotinine. Conclusions: Self-reported smoking status among people who are at high risk of lung cancer is reasonably reliable. The difference between using NNAL and cotinine appears to be minimal.

Helen G, Benowitz N, Hatsukami DK. Relationships Between Race, Gender, and Spot Urine Levels of Biomarkers of Tobacco Exposure Vary Based on How Creatinine Is Handled in Analyses

INTRODUCTION

We illustrate the differential impact of common analysis approaches to handling urinary creatinine, a measure for urine dilution, on relationships between race, gender, and biomarkers of exposure measured in spot urine.

METHODS

In smokers, spot urine levels of total nicotine equivalents (TNE, sum of total nicotine, total cotinine, and total 3'-hydroxycotinine) and total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) overall and per cigarette were examined. Relationships between race (African Americans [AA] n = 373, Whites n = 758) or gender (males n = 629, females n = 502) and TNE or NNAL were examined using the following approaches to handling creatinine: (1) unadjusted/unstandardized; (2) standardization; (3) adjustment as a covariate. Significance was considered at p < .05.

RESULTS

Creatinine was higher in AA versus Whites (1.19 vs. 0.96 mg/mL; p < .0001) and in males versus females (1.21 vs. 0.84 mg/mL; p < .0001). Independent of how creatinine was handled, TNE was lower among AA than Whites (TNE ratios AA vs. Whites: 0.67-0.84; p's < .05). Unadjusted TNE per cigarette was higher among AA versus Whites (ratio 1.12; p = .0411); however, the relationship flipped with standardization (ratio 0.90; p = .0360) and adjustment (ratio 0.95; p = .3165). Regarding gender, unadjusted TNE was higher among males versus females (ratio 1.13; p = .0063), but the relationship flipped with standardization (ratio 0.79; p < .0001) or adjustment (ratio 0.89; p = .0018). Unadjusted TNE per cigarette did not differ across gender (ratio 0.98; p = .6591), but lower levels were found in males versus females with standardization (ratio 0.68; p < .0001) and adjustment (ratio 0.74; p < .0001). NNAL displayed similar patterns.

CONCLUSIONS

Relationships between race, gender, and spot urine levels of biomarkers of exposure can vary greatly based on how creatinine is handled in analyses.

IMPLICATIONS

Lack of appropriate methods can lead to discrepancies across reports on variability of urinary biomarkers by race and gender. We recommend that for any analyses of biomarkers of exposure measure in spot urine samples across race, gender, or other population subgroups that differ in urinary creatinine levels, sensitivity analyses comparing the different methods for handling urinary creatinine should be conducted. If methods result in discrepant findings, this should be clearly noted and discussed.

Korean male active smokers: quantifying their smoking habits and the transformation factor among biomarkers in urine and blood

OBJECTIVES

The aim of the study was to investigate the correlations within the levels of biomarkers in different biological matrices, along with smoking topography variables, among active male smokers in Korea. Accordingly, we defined a transformation factor to convert level of tobacco smoke exposure and impact biomarkers from different biometrics.

METHODS

We examined smoking topography of recruited volunteers using a self-reporting survey. The level of tobacco smoke exposure and impact biomarkers in subjects' urine and blood were analysed. Results were used to assess the correlations between the topography survey items with biomarkers in biological matrices. The relationship between the biomarkers in urine and blood was analysed. Accordingly, we defined a transformation factor as the ratio of different biomarkers in urine and blood matrices.

RESULTS

Significant correlations among smoking topography variables and biomarkers were found. Besides, a strong significant association was found among urine and blood cotinine (ρ = 0.817) and NMR (ρ = 0.905). Urine vs blood cotinine and NMR transformation factors were calculated to be 6.17 L-Blood/g-Creatinine and 10.2, respectively.

CONCLUSIONS

The validated transformation factor connects epidemiological cohort studies with tobacco smoking exposure risk assessment. Hence, this study might be beneficial for further habit-based smoking risk assessments to obtain successful regional cession policies.

PhenX: Host: Biobehavioral measures for tobacco regulatory research

A working group (WG) of experts from diverse fields related to nicotine and tobacco addiction was constituted to identify constructs and measures for the PhenX (Phenotypes and eXposures) Tobacco Regulatory Research (TRR) Host: Biobehavioral Collection with potential relevance to users of both conventional and newer tobacco products. This paper describes the methods and results the WG used to identify, select, approve and place measures in the PhenX TRR Collection. The WG recognised 13 constructs of importance to guide their categorisation of measures already in the PhenX Toolkit ('complementary measures') and to identify novel or improved measures of special relevance to tobacco regulatory science. In addition to the 22 complementary measures of relevance to tobacco use already in the PhenX Toolkit, the WG identified and recommended nine additional Host: Biobehavioral measures characterising the use, exposure and health outcomes of tobacco products for application to TRR. Of these, five were self-administered or interviewer-administered measures: amount, type and frequency of recent tobacco use; flavor preference in e-cigarette users (adult and youth); pregnancy status and tobacco use; pregnancy status-mother and baby health and withdrawal from tobacco use. The remaining four measures were laboratory-based: cotinine in serum, expired carbon monoxide, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol in urine and cue reactivity. Although a number of validated tools are now available in the Host: Biobehavioral Collection, several gaps were identified, including a need to develop and test the identified measures in adolescent samples and to develop or identify measures of nicotine dependence, tolerance and withdrawal associated with newer non-combusted tobacco products.

Betel quid containing safrole enhances metabolic activation of tobacco specific 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)

Cigarette smoking (CS) and betel quid (BQ) chewing are two known risk factors that have synergistic potential for the enhancing the development of oral squamous cell carcinoma (OSCC) in Taiwan. Most mutagens and carcinogens are metabolically activated by cytochrome P450 (CYP450) to exert their mutagenicity or carcinogenicity. Previous studies have shown that metabolic activation of the tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), by CYP2A6 activity determines NNK-induced carcinogenesis. In addition, safrole affects cytochrome P450 activity in rodents. However, the effect of BQ safrole on the metabolism of tobacco-specific NNK and its carcinogenicity remains elusive. This study demonstrates that safrole (1 mg/kg/d) induced CYP2A6 activity, reduced urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) levels, and increased NNK-induced DNA damage, including N7-methylguanine, 8-OH-deoxyguanosine and DNA strand breaks in a Syrian golden hamster model. Furthermore, altered NNK metabolism and increased NNK-induced DNA damage were also observed in healthy subjects with CS and BQ chewing histories compared to healthy subjects with CS histories. In conclusion, BQ containing safrole induced tobacco-specific NNK metabolic activation, resulting in higher NNK-induced genotoxicity. This study provides valuable insight into the synergistic mechanisms of CS- and BQ-induced OSCC.

Associations of Cigarettes Smoked Per Day with Biomarkers of Exposure Among U.S. Adult Cigarette Smokers in the Population Assessment of Tobacco and Health (PATH) Study Wave 1 (2013-2014)

BACKGROUND

The dose-response relationships between number of cigarettes smoked per day (CPD) and health outcomes, such as cancer and heart disease, are well established, but much less is known about the relationships between CPD and biomarkers of exposure.

METHODS

We analyzed biomarker data by CPD from more than 2,700 adult daily cigarette smokers in Wave 1 of the Population Assessment of Tobacco and Health Study. Tobacco use categories consisted of exclusive cigarette smokers, dual cigarette and e-cigarette users, and dual cigarette and smokeless tobacco users.

RESULTS

Biomarker concentrations consistently increased with CPD for each tobacco user group, although concentrations tended to level off at high smoking levels, such as those at and above 20 CPD. Dual cigarette and e-cigarette users had higher levels of some biomarkers such as Total Nicotine Equivalents-2 (P = 0.0036) than exclusive cigarette smokers, and dual cigarette and smokeless tobacco users had higher levels of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (P < 0.0001) and N'-nitrosonornicotine (P = 0.0236) than exclusive cigarette smokers.

CONCLUSIONS

Among daily smokers, exposure to tobacco toxicants and constituents exhibits a dose-response relationship by number of cigarettes smoked, but the relationship is not necessarily linear in form. Dual users of cigarettes with either e-cigarettes or smokeless tobacco are exposed to higher levels of certain toxicants and carcinogens than exclusive cigarette smokers.

IMPACT

Availability of biomarker data by CPD may aid in comparisons between cigarette smoking and use of new and potentially reduced exposure tobacco products, which may result in different levels of constituent and toxicant exposure.

Counselling for smoking cessation during pregnancy reduces tobacco-specific nitrosamine (NNAL) concentrations: A randomized controlled trial

INTRODUCTION

Smoking cessation during pregnancy is beneficial to both the mother and child. Our objective was to assess if an intensive smoking cessation intervention for pregnant women increases: a) rates of smoking cessation, and b) reduces exposure to tobacco-specific carcinogens during pregnancy.

METHODS

A two-group single-blinded parallel randomized controlled trial (RCT) was conducted involving 84 pregnant smokers in either a high intensity (n=42) or minimal contact control group (n=42). Women assigned to the high intensity smoking cessation intervention group received a single 30-minute behavioural counselling session and a tailored self-help booklet. The primary outcome measures were: 7-day point prevalence abstinence measured by selfreport and urine cotinine levels, and maternal tobacco specific carcinogens nitrosamine (NNAL) urine concentrations assessed at 32 weeks of gestation.

RESULTS

A significantly greater percentage of pregnant smokers quit smoking in the high intensity group compared to the low intensity control group (45.2% vs 21.4%; p=0.001). A significant decrease in urine cotinine concentrations was documented in the experimental group (-140.74 ± 361.70 ng/mL; p=0.004), with no significant decrease documented in the control group. A significant decrease in NNAL levels was also documented in the experimental group (158.17 ± 145.03 pg/mL before, 86.43 ± 112.54 pg/mL after; p=0.032) with no significant changes in the control group.

CONCLUSIONS

The high intensity intervention tested resulted in significantly greater cessation rates. Intensive smoking cessation interventions can be effective in reducing fetal exposure to NNAL. This is the first trial to report on NNAL tobacco-specific carcinogen concentrations before and after an intervention for smoking cessation during pregnancy.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01210118.

ABBREVIATIONS

5Αs: ask, advise, asses, assist, arrange; GHQ: general health questionnaire; ANOVA: analysis of variance; RCT: randomized control trials; NNAL: 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol.

Secondhand exposure to aerosol from electronic cigarettes: pilot study of assessment of tobacco-specific nitrosamine (NNAL) in urine

OBJECTIVE

To assess the levels of a tobacco-specific nitrosamine (NNAL) in non-smokers passively exposed to the second-hand aerosol (SHA) emitted from users of electronic cigarettes (e-cigarettes).

METHOD

We conducted an observational study involving 55 non-smoking volunteers divided into three groups: 25 living at home with conventional smokers, 6 living with e-cigarette users, and 24 in control homes (smoke-free homes). We obtained urine samples from all volunteers to determine NNAL.

RESULTS

We detected NNAL in the urine of volunteers exposed to e-cigarettes (median:0.55 pg/mL; interquartile range: 0.26-2.94 pg/mL). The percentage of urine samples with quantifiable NNAL differed significantly among the three groups of homes: 29.2%, 66.7% and 76.0%, respectively (p=0.004).

CONCLUSIONS

We found NNAL nitrosamine in urine samples from people exposed to SHA from e-cigarettes. However, these results could be confirmed with more studies with larger sample sizes.

Trends Over Time in Tobacco-Specific Nitrosamines (TSNAs) in Whole Tobacco and Smoke Emissions From Cigarettes Sold in Canada

Introduction

Tobacco-specific nitrosamines (TSNAs) are potent carcinogens. Levels of TSNAs can be modified through manufacturing practices. In the 2000s, TSNA levels in cigarettes sold in Canada were reduced by changes in tobacco curing processes. The current study examined TSNA levels over the following decade to examine trends over time.

Methods

Data submitted to Health Canada under the Tobacco Reporting Regulations were used to examine whole tobacco constituents for 1809 brands and mainstream smoke emissions for 191 brands manufactured by Canada's three leading cigarette companies from 2005 through 2011/12 using one-way analysis of variances (ANOVAs) and linear regression models.

Results

Levels of N-nitrosoanatabine (NAT) (p < .001) and 4-(methylnitrosamino-1-(3-pyridyl)-1-butanone (NNK) (p < .001) in whole tobacco showed significant differences over time, decreasing between 2005 and 2007, and generally increasing from 2007 through 2012. Levels of all TSNAs in mainstream smoke emissions reflected a similar pattern: N-nitrosoanabasine (NAB) (p < .001), NAT (p < .001), NNK (p < .001), and N'-nitrosonornicotine (NNN) (p = .021). Linear regression analyses showed that TSNA levels varied by manufacturer over time in whole tobacco for NAT, NNK, and NNN (p < .001 for all), and in smoke emissions for NAB, NAT, NNK, and NNN (p < .001 for all).

Conclusions

The findings indicate that levels of TSNAs in whole tobacco and smoke emissions of cigarettes sold in Canada increased from 2007 through 2011/12, following initial reductions over the previous 2 years. Differences in TSNA levels between companies raise questions about manufacturing practices that may be responsible for these changes. Although increased levels of carcinogenic TSNAs may be alarming, it remains unclear whether these differences translate into differences in health risk.

Implications

The wide variation of TSNAs within the Canadian market across time and across cigarette companies demonstrates the feasibility of reducing the levels of these potent carcinogens. Although it is unclear whether changes made to levels of TSNAs will result in less tobacco-related disease, the tobacco industry bears a responsibility to minimize the harm from smoking to the fullest extent possible.

Comparison of Urine 4-(Methylnitrosamino)-1-(3)Pyridyl-1-Butanol and Cotinine for Assessment of Active and Passive Smoke Exposure in Urban Adolescents

Background: Many adolescents are exposed to tobacco smoke, from either active smoking (CS) or secondhand smoke (SHS) exposure. Tobacco-specific biomarkers of exposure include cotinine (detects use in past 2-4 days) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL; detects use for a month or longer). NNAL is expected to detect more intermittent tobacco exposure. We compared NNAL and cotinine as biomarkers of exposure to tobacco in urban adolescents and determined the optimal NNAL cutoff point to distinguish CS from SHS exposure.Methods: Surplus urine samples, collected from 466 adolescents attending pediatric well or urgent care visits at Zuckerberg San Francisco General Hospital in 2013 to 2014, were assayed for cotinine and NNAL.Results: Ninety-four percent of adolescents had measurable levels of NNAL compared with 87% for cotinine. The optimal NNAL cutoff point to distinguish CS from SHS was 9.6 pg/mL by latent class or 14.4 pg/mL by receiver-operating characteristic analysis. Cotinine and NNAL were strongly correlated, but the correlation slopes differed for active versus SHS-exposed adolescents. Among nonsmokers, NNAL levels were significantly higher in African American (median, 3.3 pg/mL) compared with other groups (0.9-1.9 pg/mL), suggesting greater exposure to SHS.Conclusions: Urine NNAL screening finds a large majority (94%) of urban adolescents are exposed to tobacco. African Americans are exposed to higher levels of SHS than other ethnic/racial groups.Impact: SHS is associated with significant medical morbidity in adolescents. Routine biochemical screening with NNAL or cotinine detects high prevalence of SHS exposure and should be considered as a tool to reduce SHS exposure in high-risk populations. Cancer Epidemiol Biomarkers Prev; 27(3); 254-61. ©2018 AACR.

Metastasis to the F344 Rat Pancreas from Lung Cancer Induced by 4-(Methylnitrosamino)- 1-(3-pyridyl)-1-butanone and Enantiomers of Its Metabolite 4-(Methylnitrosamino)-1-(3-pyridyl)- 1-butanol, Constituents of Tobacco Products

Lung cancer is the most common cause of cancer-related deaths in humans worldwide. There is strong evidence that the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and its metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) play an important role in carcinogenesis caused by tobacco products. NNK and racemic NNAL are reported to induce lung and pancreatic tumors in rats. The carcinogenicity in Fischer 344 rats of NNK, NNAL, and its enantiomers ( R)-NNAL and ( S)-NNAL has been studied recently, and all test compounds induced significant numbers of lung tumors. We report here the detailed histopathological and immunohistochemical characterization of these tumors and their aggressive nature as shown by their metastasis locally and to the pancreas. The spectrum of treatment-related histopathological findings comprised pulmonary alveolar/bronchiolar (A/B) epithelial hyperplasia, A/B adenomas, and A/B carcinomas. A/B carcinomas frequently exhibited local invasion/metastasis within the mediastinum and thoracic cavity and distant metastasis to the pancreas that was confirmed by immunohistochemistry using the lung-specific markers prosurfactant protein-C and club (Clara) cell-10. Our observation regarding metastasis to the pancreas was an important, and unexpected, finding in this study both for the experimental animal model and potential human relevance.

Carcinogen Exposure among Canadian Tobacco Users: Changes in NNK Exposure from 2007-2009 through 2012-2013

Background: Tobacco-specific nitrosamines (TSNAs) are a class of carcinogens found in tobacco products, whose levels can vary considerably depending on tobacco blends and manufacturing processes. The current study examined whether recent increases in levels of the TSNA NNK [4-(methylnitrosamino-1-(3-pyridyl)-1-butanone] in Canadian cigarettes translated into differences in exposure among Canadian tobacco users.Methods: Nationally representative data from the Canadian Health Measures Survey (CHMS) were used to measure levels of total urinary NNAL [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol], a metabolite of the TSNA NNK, among tobacco users. Data from CHMS Cycle 3 (2012-13) were used to examine NNAL, and linear regression was used to examine predictors. Data from CHMS Cycle 1 (2007-09) and Cycle 3 (2012-13) were used to examine changes in NNAL over time.Results: From 2007-2009 through 2012-2013, levels of creatinine-corrected NNAL increased by 64% (P < 0.0001). Levels of NNAL in 2012-2013 were higher among older respondents (P = 0.04), among females (P = 0.03), among respondents identifying as "white" and "Aboriginal" (P < 0.0001), and among those with greater daily cigarette consumption (P < 0.001), as well as greater levels of urinary free cotinine (P < 0.0001) and urinary creatinine (P < 0.0001).Conclusions: The findings indicate that exposure to the TSNA NNK among Canadian tobacco users has increased considerably from 2007-2009 through 2012-2013, in parallel to changes in TSNA levels in Canadian cigarettes. In the absence of epidemiologic data, it is unclear whether this change translates into increased risk.Impact: The study findings have potential implications for tobacco manufacturers, who bear a responsibility to reduce levels of tobacco carcinogens to the full extent possible. Cancer Epidemiol Biomarkers Prev; 27(3); 262-7. ©2018 AACR.

Review of biomarkers to assess the effects of switching from cigarettes to modified risk tobacco products

Context: One approach to reducing the harm caused by cigarette smoking, at both individual and population level, is to develop, assess and commercialize modified risk alternatives that adult smokers can switch to. Studies to demonstrate the exposure and risk reduction potential of such products generally involve the measuring of biomarkers, of both exposure and effect, sampled in various biological matrices.Objective: In this review, we detail the pros and cons for using several biomarkers as indicators of effects of changing from conventional cigarettes to modified risk products.Materials and methods: English language publications between 2008 and 2017 were retrieved from PubMed using the same search criteria for each of the 25 assessed biomarkers. Nine exclusion criteria were applied to exclude non-relevant publications.Results: A total of 8876 articles were retrieved (of which 7476 were excluded according to the exclusion criteria). The literature indicates that not all assessed biomarkers return to baseline levels following smoking cessation during the study periods but that nine had potential for use in medium to long-term studies.Discussion and conclusion: In clinical studies, it is important to choose biomarkers that show the biological effect of cessation within the duration of the study.

Biomarkers of exposure to new and emerging tobacco delivery products

Accurate and reliable measurements of exposure to tobacco products are essential for identifying and confirming patterns of tobacco product use and for assessing their potential biological effects in both human populations and experimental systems. Due to the introduction of new tobacco-derived products and the development of novel ways to modify and use conventional tobacco products, precise and specific assessments of exposure to tobacco are now more important than ever. Biomarkers that were developed and validated to measure exposure to cigarettes are being evaluated to assess their use for measuring exposure to these new products. Here, we review current methods for measuring exposure to new and emerging tobacco products, such as electronic cigarettes, little cigars, water pipes, and cigarillos. Rigorously validated biomarkers specific to these new products have not yet been identified. Here, we discuss the strengths and limitations of current approaches, including whether they provide reliable exposure estimates for new and emerging products. We provide specific guidance for choosing practical and economical biomarkers for different study designs and experimental conditions. Our goal is to help both new and experienced investigators measure exposure to tobacco products accurately and avoid common experimental errors. With the identification of the capacity gaps in biomarker research on new and emerging tobacco products, we hope to provide researchers, policymakers, and funding agencies with a clear action plan for conducting and promoting research on the patterns of use and health effects of these products.

Cigarette Filter Ventilation and its Relationship to Increasing Rates of Lung Adenocarcinoma

The 2014 Surgeon General's Report on smoking and health concluded that changing cigarette designs have caused an increase in lung adenocarcinomas, implicating cigarette filter ventilation that lowers smoking machine tar yields. The Food and Drug Administration (FDA) now has the authority to regulate cigarette design if doing so would improve public health. To support a potential regulatory action, two weight-of-evidence reviews were applied for causally relating filter ventilation to lung adenocarcinoma. Published scientific literature (3284 citations) and internal tobacco company documents contributed to causation analysis evidence blocks and the identification of research gaps. Filter ventilation was adopted in the mid-1960s and was initially equated with making a cigarette safer. Since then, lung adenocarcinoma rates paradoxically increased relative to other lung cancer subtypes. Filter ventilation 1) alters tobacco combustion, increasing smoke toxicants; 2) allows for elasticity of use so that smokers inhale more smoke to maintain their nicotine intake; and 3) causes a false perception of lower health risk from "lighter" smoke. Seemingly not supportive of a causal relationship is that human exposure biomarker studies indicate no reduction in exposure, but these do not measure exposure in the lung or utilize known biomarkers of harm. Altered puffing and inhalation may make smoke available to lung cells prone to adenocarcinomas. The analysis strongly suggests that filter ventilation has contributed to the rise in lung adenocarcinomas among smokers. Thus, the FDA should consider regulating its use, up to and including a ban. Herein, we propose a research agenda to support such an effort.

Greater Coronary Heart Disease Risk With Lower Intensity and Longer Duration Smoking Compared With Higher Intensity and Shorter Duration Smoking: Congruent Results Across Diverse Cohorts

INTRODUCTION

Relative risks (RRs) for coronary heart disease (CHD) by cigarettes/day exhibit a concave pattern, implying the RR increase with each additional cigarette/day consumed decreases with greater intensity. Interpreting this pattern faces limitations, since cigarettes/day alone does not fully characterize smoking-related exposure. A more complete understanding of smoking and CHD risk requires a more comprehensive representation of smoking.

METHODS

Using Poisson regression, we applied a RR model in pack-years and cigarettes/day to analyze two diverse cohorts, the US Agricultural Health Study, with 4396 CHD events and 1 425 976 person-years of follow-up, and the Finnish Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, with 5979 CHD events and 486 643 person-years.

RESULTS

In both cohorts, the concave RR pattern with cigarettes/day was consistent with cigarettes/day modifying a linear RR association for CHD by pack-years within categories of cigarettes/day, indicating that strength of the pack-years association depended on cigarettes/day (p < .01). For example, at 50 pack-years (365 000 total cigarettes), estimated RRs of CHD were 2.1 for accrual at 20 cigarettes/day and 1.5 for accrual at 50 cigarettes/day.

CONCLUSIONS

RRs for CHD increased with pack-years with smoking intensities affecting the strength of association. For equal pack-years, smoking fewer cigarettes/day for longer duration was more deleterious than smoking more cigarettes/day for shorter duration. We have now observed inverse smoking intensity effects in multiple cohorts with differing smoking patterns and other characteristics, suggesting a common underlying phenomenon.

IMPLICATIONS

Risk of CHD increases with pack-years of smoking, but accrual intensity strongly influences the strength of the association, such that smoking fewer cigarettes/day for longer duration is more deleterious than smoking more cigarettes/day for shorter duration. This observation offers clues to better understanding biological mechanisms, and reinforces the importance of cessation rather than smoking less to reduce CHD risk.

Risk of Cardiovascular Disease from Cumulative Cigarette Use and the Impact of Smoking Intensity

BACKGROUND

Relative risks (RRs) for cardiovascular disease (CVD) by smoking rate exhibit a concave pattern, with RRs in low rate smokers exceeding a linear extrapolation from higher rate smokers. However, cigarettes/day does not by itself fully characterize smoking-related risks. A reexamination of the concave pattern using a comprehensive representation of smoking may enhance insights.

METHODS

Data were from the Atherosclerosis Risk in Communities (ARIC) Study, a prospective cohort enrolled in four areas of the US in 1987-1989. Follow-up was through 2008. Analyses included 14,233 participants, 245,915 person-years, and 3,411 CVD events.

RESULTS

The concave RRs with cigarettes/day were consistent with cigarettes/day modifying a linear RR association of pack-years with CVD (i.e., strength of the pack-years association depended on cigarettes/day, indicating that the manner of pack-years accrual impacted risk). Smoking fewer cigarettes/day for longer duration was more deleterious than smoking more cigarettes/day for shorter duration (P < 0.01). For 50 pack-years (365,000 cigarettes), estimated RRs of CVD were 2.1 for accrual at 20 cigarettes/day and 1.6 for accrual at 50 cigarettes/day. Years since smoking cessation did not alter the diminishing strength of association with increasing cigarettes/day. Analyses that accounted for competing risks did not affect findings.

CONCLUSION

Pack-years remained the primary determinant of smoking-related CVD risk; however, accrual influenced RRs. For equal pack-years, smoking fewer cigarettes/day for longer duration was more deleterious than smoking more cigarettes/day for shorter duration. This observation provides clues to better understanding the biological mechanisms, and reinforces the importance of cessation rather than smoking less to reduce CVD risk.

Biomarkers of Tobacco Exposure: Summary of an FDA-Sponsored Public Workshop

Since 2009, the FDA Center for Tobacco Products (CTP) has had the authority to regulate the manufacturing, distribution, and marketing of tobacco products in order to reduce the death and disease caused by tobacco use. Biomarkers of exposure pertain to actual human exposure to chemicals arising from tobacco use and could play an important role across a number of FDA regulatory activities, including assessing new and modified-risk tobacco products and identifying and evaluating potential product standards. On August 3-4, 2015, FDA/CTP hosted a public workshop focused on biomarkers of exposure with participants from government, industry, academia, and other organizations. The workshop was divided into four sessions focused on: (i) approaches to evaluating and selecting biomarkers; (ii) biomarkers of exposure and relationship to disease risk; (iii) currently used biomarkers of exposure and biomarkers in development; and (iv) biomarkers of exposure and the assessment of smokeless tobacco and electronic nicotine delivery systems. This article synthesizes the main findings from the workshop and highlights research areas that could further strengthen the science around biomarkers of exposure and help determine their application in tobacco product regulation. Cancer Epidemiol Biomarkers Prev; 26(3); 291-302. ©2016 AACR.

Assessment of tobacco specific nitrosamines (TSNAs) in oral fluid as biomarkers of cancer risk: A population-based study

BACKGROUND

Smoke-free laws are expected to reduce smoking habits and exposure to secondhand smoke. The objective of this study was the measurement of tobacco specific carcinogens (TSNAs) in oral fluid to assess the most suitable biomarker of cancer risk associated with tobacco smoke.

METHODS

TSNAs, N'-nitrosonornicotine (NNN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), as well as nicotine and cotinine were measured in oral fluid samples from 166 smokers and 532 non-smokers of the adult population of Barcelona, Spain. A simple method with an alkaline single liquid-liquid extraction with dichloromethane/isopropanol was used and lower limits of quantification for cotinine, NNN, NNK and NNAL were set at 0.10ng/mL, 1.0, 2.0 and 0.50pg/mL respectively. The NNN/cotinine ratio was also calculated.

RESULTS

NNN was the most abundant TSNA present in oral fluid with a significant difference between smokers and non-smokers (mean concentrations of 118 and 5.3pg/mL, respectively, p<0.001). NNK and NNAL were detectable in fewer samples. NNN and cotinine concentrations had a moderate correlation within both groups (Spearman's rank correlation coefficient of 0.312, p<0.001 in smokers and 0.279, p=0.022 in non-smokers). NNN/cotinine ratio was significantly higher (p<0.001) in non-smokers than in smokers, in line with equivalent findings for the NNAL/cotinine ratio in urine.

CONCLUSIONS

TSNAs are detectable in oral fluid of smokers and non-smokers. NNN is the most abundant, in line with its association with esophageal and oral cavity cancers. The NNN/cotinine ratio confirms the relative NNN increase in second hand smoke. Findings provide a new oral fluid biomarker of cancer risk associated with exposure to tobacco smoke.

Nicotine and Toxicant Exposure among U.S. Smokeless Tobacco Users: Results from 1999 to 2012 National Health and Nutrition Examination Survey Data

BACKGROUND

It has been suggested that smokeless tobacco users have high nicotine and toxicant exposure, but studies with nationally representative data have been limited.

METHODS

We analyzed biomarkers of tobacco exposure for 23,684 adult participants from the National Health and Nutrition Examination Survey from 1999 to 2012. The biomarkers analyzed were serum cotinine, urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), blood lead, blood cadmium, blood mercury, urinary arsenic, and urinary N-acetyl-S-(2-cyanoethyl)-L-cysteine. We calculated geometric mean concentrations for each biomarker by tobacco use category and geometric mean ratios adjusting for demographic factors.

RESULTS

Exclusive smokeless tobacco users had higher geometric mean concentrations of serum cotinine [178.9 ng/mL, 95% confidence interval (CI), 145.5-220.0] and NNAL (583.0 pg/mg creatinine, 95% CI, 445.2-763.5) than exclusive cigarette smokers (130.6 ng/mL, 95% CI, 122.3-139.6 and 217.6 pg/mg creatinine, 95% CI, 193.0-245.2, respectively). Smokeless tobacco users also had higher concentrations of blood lead compared with nontobacco users (adjusted geometric mean ratio = 1.30, 95% CI, 1.21-1.38). Based on limited sample sizes, NNAL concentrations for smokeless tobacco users appear to have declined from 2007 to 2008 (geometric mean = 1013.7 pg/mg creatinine, 95% CI, 738.9-1390.8) to 2011 to 2012 (geometric mean = 325.7 pg/mg creatinine, 95% CI, 159.6-664.9).

CONCLUSIONS

Exclusive smokeless tobacco users have higher observed levels of exposure to nicotine and carcinogenic tobacco-specific nitrosamines, as measured by cotinine and NNAL biomarker concentrations, than exclusive cigarette smokers. These patterns in NNAL levels for smokeless tobacco users may be changing over time.

IMPACT

High exposure to harmful constituents among smokeless tobacco users is a continuing health issue.

Ratio-based vs. model-based methods to correct for urinary creatinine concentrations

Creatinine-corrected urinary analyte concentration is usually computed as the ratio of the observed level of analyte concentration divided by the observed level of the urinary creatinine concentration (UCR). This ratio-based method is flawed since it implicitly assumes that hydration is the only factor that affects urinary creatinine concentrations. On the contrary, it has been shown in the literature, that age, gender, race/ethnicity, and other factors also affect UCR. Consequently, an optimal method to correct for UCR should correct for hydration as well as other factors like age, gender, and race/ethnicity that affect UCR. Model-based creatinine correction in which observed UCRs are used as an independent variable in regression models has been proposed. This study was conducted to evaluate the performance of ratio-based and model-based creatinine correction methods when the effects of gender, age, and race/ethnicity are evaluated one factor at a time for selected urinary analytes and metabolites. It was observed that ratio-based method leads to statistically significant pairwise differences, for example, between males and females or between non-Hispanic whites (NHW) and non-Hispanic blacks (NHB), more often than the model-based method. However, depending upon the analyte of interest, the reverse is also possible. The estimated ratios of geometric means (GM), for example, male to female or NHW to NHB, were also compared for the two methods. When estimated UCRs were higher for the group (for example, males) in the numerator of this ratio, these ratios were higher for the model-based method, for example, male to female ratio of GMs. When estimated UCR were lower for the group (for example, NHW) in the numerator of this ratio, these ratios were higher for the ratio-based method, for example, NHW to NHB ratio of GMs. Model-based method is the method of choice if all factors that affect UCR are to be accounted for.

Tobacco Use, Insulin Resistance, and Risk of Type 2 Diabetes: Results from the Multi-Ethnic Study of Atherosclerosis

INTRODUCTION

Tobacco use is associated with insulin resistance and incident diabetes. Given the racial/ethnic differences in smoking patterns and incident type 2 diabetes our objective was to evaluate the association between tobacco use and insulin resistance (IR) as well as incident type 2 diabetes mellitus in a contemporary multiethnic cohort.

METHODS AND RESULTS

We studied 5,931 Multi- Ethnic Study of Atherosclerosis (MESA) participants who at baseline were free of type 2 diabetes (fasting glucose ≥7.0 mmol/l (126 mg/dl) and/or use of insulin or oral hypoglycemic medications) categorized by self-reported tobacco status and reclassified by urinary cotinine (available in 58% of participants) as never, current or former tobacco users. The association between tobacco use, IR (fasting plasma glucose, insulin, and the homeostatic model assessment of insulin resistance (HOMA-IR)) and incident diabetes over 10 years was evaluated using multivariable linear regression and Cox proportional hazards models, respectively. Mean age of the participants was 62 (±10) years, 46% were male, 41% Caucasian, 12% Chinese, 26% African American and 21% Hispanic/Latino. IR biomarkers did not significantly differ between current, former, and never cigarette users (P >0.10) but showed limited unadjusted differences for users of cigar, pipe and smokeless tobacco (All P <0.05). Fully adjusted models showed no association between dose or intensity of tobacco exposure and any index of IR. When stratified into participants that quit smoking vs. those who continued smoking during the 10-year study there was no difference in serum glucose levels or frequency of diabetes. In fully adjusted models, there was no significant difference in diabetes risk between former or current cigarette smokers compared to never smokers [HR (95% CI) 1.02 (0.77,1.37) and 0.81 (0.52,1.26) respectively].

CONCLUSION

In a contemporary multi-ethnic cohort, there was no independent association between tobacco use and IR or incident type 2 diabetes. The role smoking plays in causing diabetes may be more complicated than originally thought and warrants more in-depth large contemporary multi-ethnic studies.

Assessing exposure to tobacco-specific carcinogen NNK using its urinary metabolite NNAL measured in US population: 2011-2012

Carcinogenic tobacco-specific nitrosamines (TSNAs) such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) are found only in tobacco and derived products. Food and Drug Administration of the United States (US FDA) lists NNK as one of the 93 harmful and potentially harmful constituents (HPHCs) found in tobacco products and tobacco smoke. The aim of this study was to use the urinary concentration of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), a major metabolite of NNK, to quantitatively estimate exposure to NNK in the US general population. In 2011-2012, the Centers for Disease Control and Prevention's National Health and Nutrition Examination Survey (NHANES) collected urine and serum samples from a representative sample of US residents. We used a serum cotinine cutoff of 10 ng/ml with combination of questionnaire data to select non-users from cigarette users and used self-reported data to determine different tobacco product user groups. We estimated the absorbed total daily dose of NNK using a probabilistic method based on a two-compartment model. The geometric mean (GM) for the daily dose of NNK among smokers aged 12-16 years was significantly higher than that for non-users at the same age stage exposed to second-hand smoke (SHS) (P<0.001). Among those exposed to SHS, the GM for daily dose of NNK in young children (6-11 years) was nearly three times of those for adults in the age range 21-59 years. Among cigarette users, non-Hispanic Whites had the highest NNK daily dose and Mexican Americans had the lowest levels. Exclusive snuff or chewing product users had significantly higher daily dose of NNK than did cigarette smokers. Our study found that the maximum daily dose of NNK for children aged from 6 to 11 years and that for a significant percentage of cigarette users, chewing product and snuff users were higher than an estimated provisional "reference" risk level.

Exposure and Metabolic Activation Biomarkers of Carcinogenic Tobacco-Specific Nitrosamines

Lung cancer is the leading cause of cancer death in the world, and cigarette smoking is its main cause. Oral cavity cancer is another debilitating and often fatal cancer closely linked to tobacco product use. While great strides have been made in decreasing tobacco use in the United States and some other countries, there are still an estimated 1 billion men and 250 million women in the world who are cigarette smokers and there are hundreds of millions of smokeless tobacco users, all at risk for cancer. Worldwide, lung cancer kills about three people per minute. This Account focuses on metabolites and biomarkers of two powerful tobacco-specific nitrosamine carcinogens, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN), considered to be among the main causes of lung cancer and oral cavity cancer in people who use tobacco products. Three properties of NNK and NNN are critical for successful biomarker studies: they are present in all tobacco products, they are tobacco-specific and are not found in any other product, and they are strong carcinogens. NNK and NNN are converted in humans to urinary metabolites that can be quantified by mass spectrometry as biomarkers of exposure to these carcinogens. They are also metabolized to diazonium ions and related electrophiles that react with DNA to form addition products that can be detected and quantified by mass spectrometry. These urinary metabolites and DNA addition products can serve as biomarkers of exposure and metabolic activation, respectively. The biomarkers of exposure, in particular the urinary NNK metabolites 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronides, have been extensively applied to document tobacco-specific lung carcinogen uptake in smokers and nonsmokers exposed to secondhand tobacco smoke. Highly sensitive mass spectrometric methods have been developed for quantitative analysis of these NNK metabolites as well as metabolites of NNN in human urine, blood, and toenails. Urinary and serum NNAL have been related to lung cancer risk, and urinary NNN has been related to esophageal cancer risk in prospective epidemiology studies. These results are consistent with carcinogenicity studies of NNK, NNAL, and NNN in rats, which show that NNK and NNAL induce mainly lung tumors, while NNN causes tumors of the esophagus and oral cavity. Biomarkers of metabolic activation of NNK and NNN applied in human studies include the metabolism of deuterium labeled substrates to distinguish NNK and NNN metabolism from that of nicotine and the determination of DNA and hemoglobin adducts in tissues, blood, and oral cells from people exposed to tobacco products. As these methods are continually improved in parallel with the ever increasing sensitivity and selectivity of mass spectrometers, development of a comprehensive biomarker panel for identifying tobacco users at high risk for cancer appears to be a realistic goal. Targeting high risk individuals for smoking cessation and cancer surveillance can potentially decrease the risk of developing fatal cancers.

Self-reported Tobacco use does not correlate with carcinogen exposure in smokers with head and neck cancer

OBJECTIVES/HYPOTHESIS

Head and neck squamous cell carcinoma (HNSCC) is strongly associated with tobacco use. We sought to examine the relationship between self-reported tobacco use and the level of urinary tobacco carcinogen metabolites in a cohort of patients with HNSCC.

STUDY DESIGN

Cross-sectional analysis.

METHODS

Eighty-four cigarette smokers with head and neck cancer completed tobacco and alcohol use questionnaires, and the following urinary tobacco metabolites were quantified: 1-hydroxypyrene (1-HOP), N'-nitrosonornicotine and its glucuronides (total NNN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronides (total NNAL), and cotinine. A cross-sectional analysis was performed with assessment of correlation coefficients.

RESULTS

When analyzed based on self-reported cigarettes per day (CPD), no significant correlation with any of the studied tobacco carcinogen metabolites was found. However, urinary cotinine showed significant correlation with total NNN, total NNAL, and 1-HOP. Total NNN, total NNAL, and 1-HOP showed significant correlation with each other suggesting exposure occurs to each proportionally.

CONCLUSIONS

In smokers with HNSCC, self-reported tobacco use does not predict actual carcinogen exposure. In contrast, urinary cotinine levels significantly correlate with carcinogen levels. Therefore, urinary cotinine is the preferred value for estimating carcinogen dose in these patients. 1-HOP levels were significantly associated with total NNN and total NNAL suggesting that smokers are exposed to these carcinogens proportionally. These data indicate that utilizing conventional methods of estimating tobacco exposure (CPD) may not accurately approximate exposure to tobacco carcinogens in smokers with HNSCC. These data have implications for future studies focused on screening and epidemiology of smokers with HNSCC.

LEVEL OF EVIDENCE

NA

Variation in levels of the lung carcinogen NNAL and its glucuronides in the urine of cigarette smokers from five ethnic groups with differing risks for lung cancer

BACKGROUND

Results of the Multiethnic Cohort (MEC) study demonstrated that, for the same quantity of cigarettes smoked, African Americans and Native Hawaiians have a higher risk of lung cancer compared with whites, whereas Latinos and Japanese Americans have a lower risk. We hypothesize that the uptake and/or metabolism of the lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) could explain the differences in lung cancer risk.

METHODS

We measured urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronides and their sum (total NNAL), biomarkers of NNK uptake, in 2,252 smokers from the MEC. Ethnic-specific geometric means were compared adjusting for age at urine collection, sex, creatinine and total nicotine equivalents, a marker of total nicotine uptake.

RESULTS

African Americans had the highest median total NNAL levels (1.80 pmol/mL urine) and Japanese Americans had the lowest (0.914 pmol/mL urine), with intermediate values in the other three groups. Geometric mean of total NNAL in African Americans was also highest, and in Japanese Americans it was lowest; Japanese American geometric mean was statistically different from whites (P = 0.004).

CONCLUSIONS

African Americans had higher levels of total NNAL per mL urine than whites, while Japanese Americans had lower levels, consistent with lung cancer risk among smokers in these groups. However, our data were not consistent with the high and low lung cancer risks of Native Hawaiian and Latino smokers, respectively.

IMPACT

The higher lung cancer susceptibility of African-American smokers and the lower susceptibility of Japanese-American smokers compared with whites can be explained in part by exposure to the potent lung carcinogen NNK. Cancer Epidemiol Biomarkers Prev; 24(3); 561-9. ©2014 AACR.

Combined analysis of the tobacco metabolites cotinine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol in human urine

Two of the most widely measured compounds in the urine of people who use tobacco products are cotinine, a major metabolite of the addictive constituent nicotine, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), a metabolite of the powerful lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Thousands of analyses have been reported in the literature, carried out exclusively, to the best of our knowledge, by separate methods. In the study reported here, we have developed a sensitive, accurate, and precise liquid chromatography-electrospray ionization-tandem mass spectrometry-selected reaction monitoring method for the combined analysis of total cotinine (the sum of cotinine and its glucuronide) and total NNAL (the sum of NNAL and its glucuronide). The new method quantifies naturally occurring [(13)C]cotinine to minimize problems associated with the vast differences in concentration of total cotinine and total NNAL in urine. This method should greatly facilitate future determinations of these important compounds.

Different profiles of carcinogen exposure in Chinese compared with US cigarette smokers

BACKGROUND

Differences in carcinogen exposure from different cigarette products could contribute to differences in smoking-associated cancer incidence among Chinese compared with US smokers.

METHODS

Urine concentrations of metabolites of nicotine, the tobacco-specific nitrosamine (TSNA) 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), and polycyclic aromatic hydrocarbon metabolites (PAHs) were compared in 238 Chinese and 203 US daily smokers.

RESULTS

Comparing Chinese versus US smokers, daily nicotine intake and nicotine intake per cigarette smoked were found to be similar. When normalised for cigarettes per day, urine NNAL excretion was fourfold higher in US smokers, while the excretion of urine metabolites of the PAHs fluorene, phenanthrene and pyrene metabolites was 50% to fourfold higher in Chinese smokers (all, p<0.0001). Similar results were seen when NNAL and PAHs excretion was normalised for daily nicotine intake.

CONCLUSIONS

Patterns of carcinogen exposure differ, with lower exposure to TSNA and higher exposure to PAHs in Chinese compared with US smokers. These results most likely reflect country differences in cigarette tobacco blends and manufacturing processes, as well as different environmental exposures.

TRIAL REGISTRATION NUMBER

NCT00264342.

Carcinogenicity and DNA adduct formation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and enantiomers of its metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol in F-344 rats

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is metabolized to enantiomers of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), found in the urine of virtually all people exposed to tobacco products. We assessed the carcinogenicity in male F-344 rats of (R)-NNAL (5 ppm in drinking water), (S)-NNAL (5 ppm), NNK (5 ppm) and racemic NNAL (10 ppm) and analyzed DNA adduct formation in lung and pancreas of these rats after 10, 30, 50 and 70 weeks of treatment. All test compounds induced a high incidence of lung tumors, both adenomas and carcinomas. NNK and racemic NNAL were most potent; (R)-NNAL and (S)-NNAL had equivalent activity. Metastasis was observed from primary pulmonary carcinomas to the pancreas, particularly in the racemic NNAL group. DNA adducts analyzed were O (2)-[4-(3-pyridyl)-4-oxobut-1-yl]thymidine (O (2)-POB-dThd), 7-[4-(3-pyridyl)-4-oxobut-1-yl]guanine(7-POB-Gua),O (6)-[4-(3-pyridyl)-4-oxobut-1-yl]deoxyguanosine(O (6)-POB-dGuo),the 4-(3-pyridyl)-4-hydroxybut-1-yl(PHB)adductsO (2)-PHB-dThd and 7-PHB-Gua, O (6)-methylguanine (O (6)-Me-Gua) and 4-hydroxy-1-(3-pyridyl)-1-butanone (HPB)-releasing adducts. Adduct levels significantly decreased with time in the lungs of rats treated with NNK. Pulmonary POB-DNA adducts and O (6)-Me-Gua were similar in rats treated with NNK and (S)-NNAL; both were significantly greater than in the (R)-NNAL rats. In contrast, pulmonary PHB-DNA adduct levels were greatest in the rats treated with (R)-NNAL. Total pulmonary DNA adduct levels were similar in (S)-NNAL and (R)-NNAL rats. Similar trends were observed for DNA adducts in the pancreas, but adduct levels were significantly lower than in the lung. The results of this study clearly demonstrate the potent pulmonary carcinogenicity of both enantiomers of NNAL in rats and provide important new information regarding DNA damage by these compounds in lung and pancreas.

Biomarkers of exposure among U.S. cigar smokers: an analysis of 1999-2012 National Health and Nutrition Examination Survey (NHANES) data

BACKGROUND

Cigar consumption is increasing in the United States, but little information is available about exposure to toxic constituents from cigar smoking.

METHODS

We conducted a cross-sectional analysis of biomarkers of tobacco exposure among 25,522 participants from the National Health and Nutrition Examination Survey (NHANES, 1999-2012). The biomarkers analyzed were serum cotinine, urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), blood lead, blood cadmium, and urinary arsenic. We calculated geometric mean concentrations for each biomarker by tobacco use category and geometric mean ratios controlling for demographic factors.

RESULTS

Cigar smokers had higher cotinine, NNAL, and lead concentrations than nontobacco users. The geometric mean concentration [95% confidence interval (CI)] of cotinine for primary cigar smokers (i.e., current cigar/never cigarette smokers) was 6.2 (4.2-9.2) ng/mL versus 0.045 (0.043-0.048) ng/mL for nontobacco users, and the NNAL concentration was 19.1 (10.6-34.3) pg/mg creatinine for primary cigar smokers versus 1.01 (0.95-1.07) pg/mg creatinine for nontobacco users. Secondary cigar smokers (i.e., current cigar/former cigarette smokers) and dual cigar/cigarette smokers had higher cadmium concentrations than nontobacco users. Cigar smoking was associated with significantly higher concentrations of cotinine, NNAL, cadmium, and lead, after adjusting for demographic factors. Secondary cigar smokers had significantly higher cotinine and NNAL concentrations than primary cigar smokers. The NNAL concentrations in daily cigar smokers were comparable with those in daily cigarette smokers.

CONCLUSIONS

Cigar smokers have higher concentrations of several toxic and carcinogenic substances than nontobacco users.

IMPACT

Our results are consistent with epidemiologic evidence demonstrating cigar smoking as a cause of disease and premature death.

Comparison of creatinine and specific gravity for hydration corrections on measurement of the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in urine

BACKGROUND

Tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) was measured in all participants aged 6 years and older from the Centers for Disease Control and Prevention's National Health and Nutrition Examination Survey 2007-2008. The suitability of using creatinine or specific gravity for urinary NNAL correction in exposure assessment is examined in this study.

METHODS

Effects of both specific gravity and creatinine correction on urinary NNAL among smokers were investigated with multiple linear regression models using either normalization or the fitting of creatinine and specific gravity in the model as covariates.

RESULTS

When log-scaled NNAL was normalized by either creatinine or specific gravity, R(2) was slightly higher for creatinine than for specific gravity (R(2) = 0.1694 and 0.1439, for creatinine and specific gravity, respectively). When log-scaled NNAL was normalized by both factors, the R(2) was improved (R(2) = 0.2068). When specific gravity or creatinine was included as a covariate separately in the models, they were highly significant factors (P < 0.001, R(2) = 0.2226 and 0.1681 for creatinine and specific gravity, respectively). However, when both were included in the model as covariates, creatinine remained highly significant (P < 0.001), whereas the significance of specific gravity was eliminated (P = 0.4294).

CONCLUSION

This study confirms significant relationships between NNAL concentrations and both urine creatinine and specific gravity. We conclude that creatinine is the more influential and preferred variable to account for urine dilution in tobacco-specific nitrosamine exposure assessment.

It is time to regulate carcinogenic tobacco-specific nitrosamines in cigarette tobacco

The Family Smoking Prevention and Tobacco Control Act gives the U.S. Food and Drug Administration power to regulate tobacco products. This commentary calls for immediate regulation of the carcinogenic tobacco-specific nitrosamines 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN) in cigarette tobacco as a logical path to cancer prevention. NNK and NNN, powerful carcinogens in laboratory animals, have been evaluated as "carcinogenic to humans" by the International Agency for Research on Cancer. NNK and NNN are present in the tobacco of virtually all marketed cigarettes; levels in cigarette smoke are directly proportional to the amounts in tobacco. The NNK metabolite NNAL, itself a strong carcinogen, is present in the urine of smokers and nonsmokers exposed to secondhand smoke. Some of the highest levels of NNK and NNN are found in U.S. products. It is well established that factors such as choice of tobacco blend, agricultural conditions, and processing methods influence levels of NNK and NNN in cigarette tobacco and cigarette smoke. Therefore, it is time to control these factors and produce cigarettes with 100 ppb or less each of NNK and NNN in tobacco, which would result in an approximate 15- to 20-fold reduction of these carcinogens in the mainstream smoke of popular cigarettes sold in the United States.

Time to first cigarette predicts 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in adolescent regular and intermittent smokers, National Health and Nutrition and Examination Survey (NHANES) 2007-10

BACKGROUND AND AIMS

The time to first cigarette (TTFC) of the day is an indicator of nicotine intake in adults and adolescents. However, the relation between TTFC and biological markers of nicotine addiction and health risk in youths has not been well described. The current study examined whether an earlier TTFC predicts higher levels of a tobacco-specific carcinogen, 4-(methylnitrosamino)-1-(3-pyridal)-1 (NNAL), in regular and intermittent adolescent smokers and if this relation is mediated by nicotine intake (measured by cotinine) or cigarettes per day (CPD).

DESIGN

A cross-sectional analysis of a nationally representative subsample of adolescents.

SETTING

A general community sample from the 2007-08 and 2009-10 National Health and Nutrition and Examination Survey.

PARTICIPANTS

A total of 215 adolescents in the United States between the ages of 12 and 19 years who reported smoking at least once in the 5 days prior to data collection.

MEASUREMENTS

The primary outcome measure was urinary levels of NNAL.

FINDINGS

In both regular and intermittent smokers, earlier TTFC was associated dose-dependently with higher levels of NNAL (P < 0.03 in both cases). TTFC had an indirect effect on NNAL, mediated by nicotine intake (cotinine) in both regular [β = -0.08, standard error (SE) = 0.03, 95% confidence interval (CI) = -0.15, -0.03] and intermittent (β = -0.02, SE = 0.01, 95% CI = -0.05, -0.002) smokers. CPD was not found to be an important mediator of the relation between TTFC and NNAL.

CONCLUSIONS

Time between waking and the first cigarette of the day is correlated in daily and non-daily adolescent smokers with overall nicotine and therefore carcinogen intake.

Quantitative analysis of five tobacco-specific N-nitrosamines in urine by liquid chromatography-atmospheric pressure ionization tandem mass spectrometry

A liquid chromatography tandem mass spectrometry (LC/MS/MS) method was developed and validated for the determination of five total tobacco-specific N-nitrosamines (TSNA), including free and conjugated forms in urine. The limits of detection for 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, N'-nitrosonornicotine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, N'-nitrosoanatabine and N'-nitrosoanabasine were 0.6, 0.6, 10.0, 0.4 and 0.4 pg/mL, respectively, with a linear calibration range of up to 20,000 pg/mL. Intra- and inter-day precision for TSNA measurements ranged from 0.82 to 3.67% and from 2.04 to 7.73% respectively. For total TSNAs, the β-glucuronidase amount was optimized for hydrolysis time and yield. Different liquid chromatography columns and mobile phases with different pH conditions were evaluated. The validated method was then applied to 50 smoker and 30 nonsmoker urine samples. Our results suggest that this sensitive and relatively simple analytical method is suitable for application to epidemiological investigations of health risks associated with the exposure to tobacco smoke or secondhand smoke in both smokers and nonsmokers.

Identification of tobacco-specific nitrosamines as disinfection byproducts in chloraminated water

Tobacco-specific nitrosamines (TSNAs) exist in environmental waters; however, it is unknown whether TSNAs can be produced during water disinfection. Here we report on the investigation and evidence of TSNAs as a new class of disinfection byproducts (DBPs). Using five common TSNAs, including (methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) as the targets, we first developed a solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) method capable of rapidly determining these TSNAs at levels as low as 0.02 ng/L in treated water. Using this highly sensitive method, we investigated the occurrence and formation potential (FP) (precursor test conducted in the presence of chloramines) of TSNAs in treated water from two wastewater treatment plants (WWTPs) and seven drinking water treatment plants (DWTPs). NNAL was detected in the FP samples, but not in the samples before the FP test, confirming NNAL as a DBP. NNK was detected in the treated wastewater before the FP test, but its concentration increased significantly after chloramination in two of three tests. Thus, NNK could be a DBP and/or a contaminant in wastewater. Moreover, these TSNAs were detected in FP tests of wastewater-impacted DWTP plant influents in 9 of 11 samples. However, TSNAs were not detected at full-scale DWTPs, except for at one DWTP with high ammonia where breakpoint chlorination was not achieved. The concentration of the sum of five TSNAs (0.3 ng/L) was 100-fold lower than NDMA, suggesting that TSNAs have a minor contribution to total nitrosamines in water. We examined several factors in the treatment process and found that chlorine or ozone may destroy TSNA precursors and granular activated carbon (GAC) treatment may remove the precursors. Further research is warranted into the efficiency of these processes at different DWTPs using sources of varying water quality.

Biomarkers of tobacco smoke exposure and asthma severity in adults

BACKGROUND

Tobacco biomarkers including serum cotinine and urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) have been used in research settings.

PURPOSE

The goal of the study was to examine the association of cotinine and NNAL with asthma outcomes in the U.S. adult population.

METHODS

A cross-sectional design was used, using data from the National Health and Nutrition Examination Survey, 2007-2008, with participants aged >20 years with self-reported asthma (N=456). Past-year asthma exacerbations and emergency room/urgent care visits for asthma were examined. Analyses were conducted in 2013.

RESULTS

Among adult asthmatics, 50.3% reported a past-year asthma attack (61.8% smokers, 46.6% nonsmokers, p=0.029). Among these, 24.7% reported a past-year emergency/urgent visit for asthma (34.7% smokers, 20.1% nonsmokers, p=0.034). Median concentrations of cotinine and creatinine-adjusted NNAL (NNAL/Cr) were significantly higher in those with a past-year asthma attack (0.43 ng/mL and 7.28 pg/mL) than in those without (0.06 ng/mL and 2.26 pg/mL), and highest in those with past-year emergency/urgent visits (0.93 ng/mL and 28.14 pg/mL). Among nonsmokers, increasing levels of log cotinine or log NNAL/Cr, adjusted for demographics, were significantly associated with past-year asthma exacerbation (log cotinine OR=1.46 [95% CI=1.1, 1.92]; log NNAL/Cr OR=1.42 [95% CI=1.07, 1.88]) and past-year emergency/urgent visit (log cotinine OR=1.95 [95% CI=1.32, 2.88]; log NNAL/Cr OR=1.58 [95% CI=1.23, 2.02]). Among smokers, increasing biomarker levels were not significantly associated with either outcome.

CONCLUSIONS

In a population-based cross-sectional analysis, increased cotinine and NNAL were found to be associated with asthma exacerbation and healthcare use in nonsmokers with asthma. If these findings are confirmed in prospective studies, these biomarkers might be candidates for clinical indicators of risk of asthma.

High throughput liquid and gas chromatography-tandem mass spectrometry assays for tobacco-specific nitrosamine and polycyclic aromatic hydrocarbon metabolites associated with lung cancer in smokers

We developed and applied high throughput liquid and gas chromatography-tandem mass spectrometry (LC-MS/MS and GC-MS/MS) methods for the cigarette smoking-associated biomarkers 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene (PheT), which are urinary metabolites of the carcinogenic tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and the polycyclic aromatic hydrocarbon phenanthrene. NNAL and PheT levels have been linked to lung cancer in previous studies of smokers. Confirmation of these relationships will require further molecular epidemiology studies, necessitating improved methodology applicable to large numbers of small urine samples. Furthermore, NNAL is excreted in urine either unconjugated or as an N- or O-glucuronide, but little data are available on the amounts of each in urine. For the high throughput analysis of NNAL, 3 aliquots were processed from each urine sample, one for the analysis of free NNAL, one for free NNAL plus NNAL-N-Gluc, and one for total NNAL (the sum of free NNAL, NNAL-N-Gluc, and NNAL-O-Gluc). Ninety-six well plate technology was used for sample enrichment by supported liquid extraction plates, mixed mode reverse-phase/cation exchange solid-phase extraction, and LC-MS/MS analysis. For the analysis of PheT, the urine samples were cleaned up by solid-phase extraction on styrene-divinylbenzene sorbent, silylated, and analyzed by GC-MS/MS, both in 96-well format. The methods were validated analytically with respect to accuracy and precision, and applied in an ongoing molecular epidemiology study of smokers. The amount of total NNAL in smokers' urine was (mean ± SD) 1.65 ± 2.13 pmol/mL (N = 2641). Free NNAL, NNAL-N-Gluc, and NNAL-O-Gluc represented (mean ± SD) 31 ± 11%, 22 ± 14%, and 48 ± 15% of total NNAL, respectively. The amount of PheT in smokers' urine was (mean ± SD) 1.43 ± 2.16 pmol/mL (N = 2613). The methodology described here should be widely applicable in future studies of tobacco use and cancer.

NNAL exposure by race and menthol cigarette use among U.S. smokers

INTRODUCTION

Researchers have recently suggested that nicotine and carcinogen exposure as measured by biomarkers such as cotinine and NNAL (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol) does not vary with cigarettes smoked per day (CPD) among Black smokers. Researchers have also suggested that nicotine exposure does not differ between menthol and nonmenthol smokers. In this study, we examine NNAL exposure for U.S. smokers by race, CPD, and menthol cigarette use.

METHODS

We analyzed urinary NNAL concentrations for more than 1500 everyday smokers participating in the National Health and Nutrition Examination Survey from 2007-2010. For purposes of comparison, we also analyzed serum cotinine concentrations for these smokers. We used linear regression analysis to estimate mean biomarker concentrations by CPD and race/ethnicity group and to examine the association between biomarker concentrations and menthol cigarette use by race/ethnicity group, controlling for other demographic and smoking characteristics.

RESULTS

Biomarker concentrations increased with CPD for White, Black, and Hispanic smokers although NNAL concentrations leveled off for Black smokers at lower CPD levels compared with other smokers. Mean NNAL concentrations were lower among menthol smokers compared with nonmenthol smokers among smokers overall (β = -0.165, p = .032) and White smokers (β = -0.207, p = .048).

CONCLUSIONS

We find evidence in national health survey data that nicotine and carcinogen exposure generally increases with CPD across race/ethnicity groups although the pattern of NNAL exposure differs by race/ethnicity group at high CPD levels. We also find evidence of differences in NNAL exposure for menthol smokers compared with nonmenthol smokers among smokers overall and White smokers.

Menthol cigarettes, race/ethnicity, and biomarkers of tobacco use in U.S. adults: the 1999-2010 National Health and Nutrition Examination Survey (NHANES)

BACKGROUND

In the United States, cigarette flavorings are banned, with the exception of menthol. The cooling effects of menthol could facilitate the absorption of tobacco toxicants. We examined levels of biomarkers of tobacco exposure among U.S. smokers of menthol and nonmenthol cigarettes.

METHODS

We studied 4,603 White, African-American, and Mexican-American current smokers 20 years of age or older who participated in the National Health and Nutrition Examination Survey (NHANES) from 1999 through 2010 and had data on cigarette type and serum cotinine, blood cadmium, and blood lead concentrations. Urinary total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol) (NNAL) was studied in 1,607 participants with available measures.

RESULTS

A total of 3,210 (74.3%) participants smoked nonmenthol cigarettes compared with 1,393 (25.7%) participants who smoked menthol cigarettes. The geometric mean concentrations comparing smokers of nonmenthol with menthol cigarettes were 163.1 versus 175.9 ng/mL for serum cotinine; 0.95 versus 1.02 μg/L for blood cadmium; 1.87 versus 1.75 μg/dL for blood lead; and 0.27 versus 0.23 ng/mL for urine NNAL. After multivariable adjustment, the ratios [95% confidence interval (CI)] comparing smokers of menthol with nonmenthol cigarettes were 1.03 (0.95-1.11) for cotinine, 1.10 (1.04-1.16) for cadmium, 0.95 (0.90-1.01) for lead, and 0.81 (0.65-1.01) for NNAL.

CONCLUSIONS

In a representative sample of U.S. adult smokers, current menthol cigarette use was associated with increased concentration of blood cadmium, an established carcinogen and highly toxic metal, but not with other biomarkers.

IMPACT

These findings provide information regarding possible differences in exposure to toxic constituents among menthol cigarette smokers compared with nonmenthol cigarette smokers.

Tobacco-specific nitrosamine exposures in smokers and nonsmokers exposed to cigarette or waterpipe tobacco smoke

INTRODUCTION

The causal relationship between tobacco smoking and a variety of cancers is attributable to the carcinogens that smokers inhale, including tobacco-specific nitrosamines (TSNAs). We aimed to assess the exposure to TSNAs in waterpipe smokers (WPS), cigarette smokers (CS), and nonsmoking females exposed to tobacco smoke.

METHODS

We measured 2 metabolites, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronides (NNAl-Gluc) in the urine of males who were either current CS or WPS, and their wives exposed to either cigarette or waterpipe smoke in a sample of 46 subjects from rural Egypt.

RESULTS

Of the 24 current male smokers, 54.2% were exclusive CS and 45.8% were exclusive WPS. Among wives, 59.1% reported exposure to cigarette smoke and 40.9% to waterpipe smoke. The geometric mean of urinary NNAL was 0.19 ± 0.60 pmol/ml urine (range 0.005-2.58) in the total sample. Significantly higher levels of NNAL were observed among male smokers of either cigarettes or waterpipe (0.89 ± 0.53 pmol/ml, range 0.78-2.58 in CS and 0.21-1.71 in WPS) compared with nonsmoking wives (0.04 ± 0.18 pmol/ml, range 0.01-0.60 in CS wives, 0.05-0.23 in WPS wives, p = .000). Among males, CS had significantly higher levels of NNAL compared with WPS (1.22 vs. 0.62; p = .007). However, no significant difference was detected in NNAL levels between wives exposed to cigarette smoke or waterpipe smoke.

CONCLUSIONS

Cigarette smokers levels of NNAL were higher than WPS levels in males. Exposure to tobacco smoke was evident in wives of both CS and WPS. Among WPS, NNAL tended to increase with increasing numbers of hagars smoked/day.