Comparison of urine cotinine and the tobacco-specific nitrosamine metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and their ratio to discriminate active from passive smoking

Direct analysis of tobacco-specific nitrosamine NNK and its metabolite NNAL in human urine by LC-MS/MS: evidence of linkage to methylated DNA lesions

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and its urinary metabolite, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), are the most investigated carcinogenic biomarkers of tobacco-specific nitrosamines. Here, we report the development of a sensitive and selective assay based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) to simultaneously measure urinary NNK and NNAL. With the use of isotope internal standards and online solid-phase extraction, urine samples were directly analyzed without prior sample purification. The detection limits of this method were 0.13 and 0.19 pg on column for NNK and NNAL, respectively. Inter- and intra-day imprecision was <10 %. Mean recovery of NNK and NNAL in urine was 99-100 %. This method was applied to measure urinary NNK and NNAL in 101 smokers and 40 nonsmokers to assess tobacco exposure. Urinary nicotine, cotinine, N3-methyladenine (N3-MeA), and N7-methylguanine (N7-MeG) were also measured by isotope-dilution LC-MS/MS methods. The results showed that urinary NNK was not observed in all smokers. Urinary free NNAL (0.10 ± 0.09 ng/mg creatinine) and total NNAL (0.17 ± 0.14 ng/mg creatinine) were detected in all smokers. Urinary concentrations of NNAL were significantly correlated with nicotine, cotinine, N3-MeA, and N7-MeG in smokers (P < 0.001). This method enables the direct and simultaneous measurement of NNK and NNAL in urine using only 50 μL of urine. This study first demonstrated in human that urinary tobacco-specific nitrosamines metabolite (NNAL) are highly correlated with their resulting methylated DNA lesions in urine, which may help to substantiate an increased cancer risk associated with tobacco smoke exposure.

Proposed cutoff for identifying adult smokeless tobacco users with urinary total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanonol: an aggregated analysis of NHANES 2007-2010 data

INTRODUCTION

NNAL [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanonol] is a valid biomarker of tobacco use. However; no study has assessed its use in distinguishing current smokeless tobacco (SLT) users from nonusers. Therefore, this study used aggregated data from the 2007-2008 and 2009-2010 waves of the National Health and Nutrition Examination Survey to determine an optimal threshold for identifying SLT users with NNAL.

METHODS

Optimal urinary total NNAL concentrations for discriminating SLT-only users from nonusers of any tobacco were determined using receiver operating characteristic analysis. Percentage agreement between self-reported SLT use status and NNAL levels was calculated overall and by sociodemographic characteristics. All analyses were weighted and performed with Stata, Version 11, and MedCalc for Windows, Version 9.5.0.0.

RESULTS

In total, 264 individuals reported exclusively using SLT (and no other combustible tobacco product) within the past 5 days, whereas 14,824 were self-reported nonusers of any combustible or smokeless tobacco product. The optimal NNAL cutoff point was 34.0 pg/ml, which was associated with a high sensitivity (95.2%), specificity (93.4%), and overall correct classification rate (93.5%). The area under the curve was 98.3% and the corresponding Youden's Index was 88.7%. There was high agreement between the proposed NNAL cutoff point and self-reported SLT-only use (95.6%) and self-reported SLT nonuse (93.9%).

CONCLUSION

The proposed cutoff point of 34.0 pg/ml had high sensitivity and specificity and may be used by clinicians and researchers to verify or detect recent SLT use. This study also indicated that self-reported SLT use among adults is a reliable measure and has high agreement with biochemical assessment.

Optimum cutoff value of urinary cotinine distinguishing South Korean adult smokers from nonsmokers using data from the KNHANES (2008-2010)

INTRODUCTION

Cutoff values for distinguishing smokers from nonsmokers have generally been derived from studies in White populations. Even though recent population-based studies have demonstrated that cutoff values can differ by race and ethnicity, few studies have explored cutoff values among Asian populations. We established the cutoff values for urinary cotinine and cotinine:creatinine ratio (CCR) using a nationally representative South Korean adult population sample.

METHODS

Data were obtained from the Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2010 with pooled sampling weights. Adult participants (n = 11,629) aged ≥19 were included. Optimal cutoff values were determined by performing receiver operating characteristic curve analysis.

RESULTS

The optimum cutoff values for urinary cotinine and CCR for Korean adults were found to be 164ng/mL and 1122ng/mg, respectively. The application of these urinary cotinine and CCR cutoff values for the female subpopulations aged 19-34, 35-54, and ≥55 years provided sensitivities ranging from 87.1% to 93.8% and from 82.9% to 94.9%, respectively, while maintaining specificity of ≥92%. For the 3 male age-based subpopulations, we obtained sensitivities and specificities for cotinine ranging from 93.1% to 94.5% and from 92.8% to 97.0%, respectively, and for CCR ranging from 90.0% to 96.9% and from 92.2% to 96.8%, respectively.

CONCLUSIONS

Our cutoff values should allow researchers conducting environmental epidemiological or clinical studies in South Korea to distinguish adult smokers from nonsmokers effectively. However, different values may be applicable for subpopulations with different smoking prevalence rates or higher exposure levels to secondhand smoke.

Secondhand smoke exposure and osteoporosis in never-smoking postmenopausal women: the Fourth Korea National Health and Nutrition Examination Survey

SUMMARY

The association between secondhand smoke (SHS) exposure and lumbar and femoral neck osteoporosis was assessed in postmenopausal never-smoking Korean women. The presence of family members who actively smoked was associated with femoral neck osteoporosis. The number of cigarettes consumed by cohabitant smokers was positively associated with lumbar and femoral neck osteoporosis.

INTRODUCTION

This study aimed to assess the association between SHS and postmenopausal osteoporosis.

METHODS

Of 2,067 postmenopausal women (age, ≥55 years) participating in the Fourth Korea National Health and Nutrition Examination Survey, 925 never-smokers identified through interviews and urinary cotinine level verification were enrolled. Cross-sectional relationships between self-reported SHS exposure and osteoporosis of the lumbar vertebrae and femoral neck (defined using the World Health Organization T-score criteria) were investigated by bone densitometry.

RESULTS

Participants having actively smoking family members showed increased adjusted odds ratio (aOR) for femoral neck osteoporosis compared with participants not exposed to SHS (aOR, 3.68; 95 % confidence interval [CI], 1.23-10.92). Participants whose cohabitant smokers consumed any number of cigarettes per day showed increased occurrences for lumbar and femoral neck osteoporosis compared with the nonexposed group. Participants whose cohabitant smokers consumed ≥20 cigarettes/day showed increased aORs for lumbar (aOR, 5.40; 95 % CI, 1.04-28.04) and femoral neck (aOR, 4.35; 95 % CI, 1.07-17.68) osteoporosis compared with participants not exposed to SHS.

CONCLUSIONS

In postmenopausal never-smoking Korean women, exposure to SHS was positively associated with osteoporosis. This finding further emphasizes a need to identify vulnerable groups exposed to SHS to increase bone health.

Alaska Native smokers and smokeless tobacco users with slower CYP2A6 activity have lower tobacco consumption, lower tobacco-specific nitrosamine exposure and lower tobacco-specific nitrosamine bioactivation

Nicotine, the psychoactive ingredient in tobacco, is metabolically inactivated by CYP2A6 to cotinine. CYP2A6 also activates procarcinogenic tobacco-specific nitrosamines (TSNA). Genetic variation in CYP2A6 is known to alter smoking quantity and lung cancer risk in heavy smokers. Our objective was to investigate how CYP2A6 activity influences tobacco consumption and procarcinogen levels in light smokers and smokeless tobacco users. Cigarette smokers (n = 141), commercial smokeless tobacco users (n = 73) and iqmik users (n = 20) were recruited in a cross-sectional study of Alaska Native people. The participants' CYP2A6 activity was measured by both endophenotype and genotype, and their tobacco and procarcinogen exposure biomarker levels were also measured. Smokers, smokeless tobacco users and iqmik users with lower CYP2A6 activity had lower urinary total nicotine equivalents (TNE) and (methylnitrosamino)-1-(3)pyridyl-1-butanol (NNAL) levels (a biomarker of TSNA exposure). Levels of N-nitrosonornicotine (NNN), a TSNA metabolically bioactivated by CYP2A6, were higher in smokers with lower CYP2A6 activities. Light smokers and smokeless tobacco users with lower CYP2A6 activity reduce their tobacco consumption in ways (e.g. inhaling less deeply) that are not reflected by self-report indicators. Tobacco users with lower CYP2A6 activity are exposed to lower procarcinogen levels (lower NNAL levels) and have lower procarcinogen bioactivation (as indicated by the higher urinary NNN levels suggesting reduced clearance), which is consistent with a lower risk of developing smoking-related cancers. This study demonstrates the importance of CYP2A6 in the regulation of tobacco consumption behaviors, procarcinogen exposure and metabolism in both light smokers and smokeless tobacco users.

Thirty minute-exposure to aged cigarette smoke increases nasal congestion in nonsmokers

The aim of this study was to assess the effects of short exposures to experimentally aged cigarette smoke on the nose and upper airways. This crossover study compared the effects of 30-min exposures to (1) experimentally aged cigarette smoke at 1 mg/m³ particulate matter (PM)/14 ppm carbon monoxide (CO) and (2) conditioned filtered air on urinary metabolites of nicotine and tobacco-specific nitrosamines. Subjective nasal symptoms were assessed by questionnaire, objective nasal congestion was assessed by anterior rhinomanometry and nasal nitric oxide (NO) concentrations were determined. Experimentally aged cigarette smoke is a validated model for secondhand smoke (SHS). Twenty-six healthy nonsmokers (10 normal, 7 atopic/nonrhinitic, 7 atopic rhinitic, 2 nonatopic/rhinitic) were studied. A 30-min exposure to SHS increased nasal resistance in healthy nonsmokers. The rise in nasal resistance was most pronounced in rhinitic subjects. Significant increases were not noted when atopic subjects were considered independent of rhinitis status. Secondhand smoke exposure also elevated subjective nasal symptoms and urinary concentrations of metabolites of nicotine (cotinine and trans-3´-hydroxycotinine) and tobacco-specific nitrosamines [(4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL)] in all subgroups of subjects. Exposure-related, subjective nasal symptoms were significantly higher in rhinitic than in normal subjects. Significant changes in nasal NO concentrations were not detected. Data indicate a 30-min exposure to secondhand smoke at 1 mg/m³ PM increases subjective upper respiratory symptoms, increases urinary cotinine and NNAL, and produces objective nasal airflow obstruction in human subjects.

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.

The Associations Between Smoking and Occupational Categories

The implementation of smoke-free policies for workplaces and their impacts have been far from satisfactory. We investigated smoking prevalence in various occupations using data (n = 9283) from the Korea National Health and Nutrition Examination Survey collected from 2008 to 2010. Young adults who were working in the occupation categories of “service and sales,” “skilled agricultural, fishery, and forest workers,” and “crafts and machine operation” for men and “service and sales” for women showed 1.8 to 7.1 and 3.7 times higher ( P < .05) smoking prevalence compared with the reference (managers and professionals), respectively, and the highest prevalence among the 7 occupational categories that were studied. Drinking and stress level were positively associated with being current smokers. We provide quantitative evidence supporting clinicians and policy makers wishing to establish smoking-cessation programs in workplaces for young adults in South Korea, and evidence supporting the improvement of prevention by the concomitant reduction of risk factors.

Urine Cotinine for Assessing Tobacco Smoke Exposure in Korean: Analysis of the Korea National Health and Nutrition Examination Survey (KNHANES)

Background

The level of urine cotinine is an indicator of tobacco smoke exposure. The purpose of this study is to investigate urine cotinine for the purpose of assessing the smoking status of Korean smokers and non-smokers exposed to tobacco smoke.

Methods

The subjects were identified from the 2007-2009 and the 2010 data sets of the Korea National Health and Nutrition Examination Survey (KNHANES). They were assigned as non-smokers, current smokers and ex-smokers. Non-smokers were also divided into three subset groups according to the duration of smoke exposure. Each group was stratified by gender prior to analysis.

Results

The median value of urine cotinine in the male current smokers was 1,221.93 ng/mL which was the highest among all groups. The difference between levels of urine cotinine for male and the female groups was statistically significant (p<0.01). In the female group, passive smoke exposure groups reported higher urine cotinine levels than non-exposure groups (p=0.01). The cutoff point for the discrimination of current smokers from non-smokers was 95.6 ng/mL in males and 96.8 ng/mL in females. The sensitivity and specificity were 95.2% and 97.1%, respectively, in males, 96.1% and 96.5% in females. However, the determination of urine cotinine level was not useful in distinguishing between passive smoke exposure groups and non-exposure groups.

Conclusion

Urine cotinine concentration is a useful biomarker for discriminating non-smokers from current smokers. However, careful interpretation is necessary for assessing passive smoke exposure by urine cotinine concentration.

Correlates of NNAL levels among nondaily and daily smokers in the college student population

INTRODUCTION

Recent simultaneous increases in nondaily smoking and decreases in daily smoking make the identification of nondaily smokers through biomarker measures as well as the relationship of biomarker levels to smoking behaviors important topics. However, little is known about biochemical identification and carcinogen exposure of nondaily smokers. One tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), has a long half-life, making it a useful marker for long-term and intermittent tobacco exposure. Thus, we examined correlates of urine NNAL levels among nondaily and daily smokers.

METHODS

In 2011, we obtained urine samples from 64 current cigarette smokers (37 nondaily; 27 daily) in the Southeastern US and assessed participants' sociodemographics, smoking-related information, and other tobacco use. Our sample included 14 participants concurrently using other combustible tobacco products and eight concurrently using smokeless tobacco.

RESULTS

Of six participants smoking for only one day in the past 30, four had detectable NNAL levels; thus, two nondaily smokers were excluded from the remainder of the analyses. In multivariate analysis, average cigarettes per day on smoking days (B = 23.00, 95% Confidence Interval [CI] 13.81, 32.20, P < 0.001) and number of days of smokeless tobacco use (B = 17.11, CI 13.53, 20.70, P < 0.001) were associated with NNAL levels among nondaily smokers (R² = 0.234). Multivariate analysis indicated that average cigarettes per day (B = 15.83, CI 2.89, 28.76, P = 0.02) was the only significant correlate of NNAL levels among daily smokers. We used receiver operating characteristic (ROC) analyses to identify a potential urinary NNAL (normalized for creatinine) cutoff point of 81.6 pg/mL/g creatinine (88.9% sensitivity, 80.0% specificity) to discriminate nondaily from daily smokers. Excluding polytobacco-product users from these analyses provided similar results.

CONCLUSION

Different correlates of NNAL levels exist among nondaily and daily cigarette smokers. Urine NNAL demonstrates the potential to be used to discriminate nondaily from daily smokers among young adults.

Small proportions of actively-smoking patrons and high PM2.5 levels in southern California tribal casinos: support for smoking bans or designated smoking areas

Background

Nearly all California casinos currently allow smoking, which leads to potentially high patron exposure to secondhand tobacco smoke pollutants. Some argue that smoking restrictions or bans would result in a business drop, assuming > 50% of patrons smoke. Evidence in Nevada and responses from the 2008 California tobacco survey refute this assertion. The present study investigates the proportion of active smokers in southern California tribal casinos, as well as occupancy and PM_2.5 levels in smoking and nonsmoking sections.

Methods

We measured active-smoker and total-patron counts during Friday or Saturday night visits (two per casino) to smoking and nonsmoking gaming areas inside 11 southern California casinos. We counted slot machines and table games in each section, deriving theoretical maximum capacities and occupancy rates. We also measured PM_2.5 concentrations (or used published levels) in both nonsmoking and smoking areas.

Results

Excluding one casino visit with extremely high occupancy, we counted 24,970 patrons during 21 casino visits of whom 1,737 were actively smoking, for an overall active- smoker proportion of 7.0% and a small range of ~5% across casino visits (minimum of 5% and maximum of 10%). The differences in mean inter-casino active-smoker proportions were not statistically significant. Derived occupancy rates were 24% to 215% in the main (low-stakes) smoking-allowed slot or table areas. No relationship was found between observed active-smoker proportions and occupancy rate. The derived maximum capacities of nonsmoking areas were 1% to 29% of the overall casino capacity (most under 10%) and their observed occupancies were 0.1 to over 3 times that of the main smoking-allowed casino areas. Seven of twelve visits to nonsmoking areas with no separation had occupancy rates greater than main smoking areas. Unenclosed nonsmoking areas don’t substantially protect occupants from PM_2.5 exposure. Nonsmoking areas encapsulated inside smoking areas or in a separate, but unenclosed, area had PM_2.5 levels that were 10 to 60 μg/m³ and 6 to 23 μg/m³ higher than outdoor levels, respectively, indicating contamination from smoking.

Conclusions

Although fewer than roughly 10% of casino patrons are actively smoking on average, these individuals substantially increase PM_2.5 exposure for all patrons in smoking and unenclosed nonsmoking areas. Nonsmoking areas may be too inconvenient, small, or undesirable to serve a substantial number of nonsmoking patrons. Imposing indoor smoking bans, or contained smoking areas with a maximum capacity of up to 10% of the total patronage, would offer protection from PM_2.5 exposures for nonsmoking patrons and reduce employee exposures.

Chapter 6: Lung cancer in never smokers: epidemiology and risk prediction models

In this chapter we review the epidemiology of lung cancer incidence and mortality among never smokers/nonsmokers and describe the never smoker lung cancer risk models used by the Cancer Intervention and Surveillance Network (CISNET) modelers. Our review focuses on those influences likely to have measurable population impact on never smoker risk, such as secondhand smoke, even though the individual-level impact may be small. Occupational exposures may also contribute importantly to the population attributable risk of lung cancer. We examine the following risk factors in this chapter: age, environmental tobacco smoke, cooking fumes, ionizing radiation including radon gas, inherited genetic susceptibility, selected occupational exposures, preexisting lung disease, and oncogenic viruses. We also compare the prevalence of never smokers between the three CISNET smoking scenarios and present the corresponding lung cancer mortality estimates among never smokers as predicted by a typical CISNET model.

Exposure to secondhand smoke outside of a bar and a restaurant and tobacco exposure biomarkers in nonsmokers

BACKGROUND

With an increase in indoor smoking bans, many smokers smoke outside establishments and near their entrances, which has become a public health concern.

OBJECTIVES

We characterized the exposure of nonsmokers to secondhand smoke (SHS) outside a restaurant and bar in Athens, Georgia, where indoor smoking is banned, using salivary cotinine and urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL).

METHODS

In a crossover study, we assigned 28 participants to outdoor patios of a restaurant and a bar and an open-air site with no smokers on three weekend days; participants visited each site once and stayed for 3 hr. We collected saliva and urine samples immediately before and after the visits (postexposure) and on the following morning and analyzed samples for cotinine and total NNAL, respectively. Regression models were fitted and changes in biomarkers were contrasted between locations.

RESULTS

Postexposure and preexposure geometric mean salivary cotinine concentrations differed by 0.115 ng/mL [95% confidence interval (CI): 0.105, 0.126)] and by 0.030 ng/mL (95% CI: 0.028, 0.031) for bar and restaurant visits, respectively. There were no significant post- and preexposure differences in cotinine levels after control site visits, and changes after bar and restaurant site visits were significantly different from changes after control site visits (p < 0.001). Results comparing next-day and preexposure salivary cotinine levels were similar. Next-day creatinine-corrected urinary NNAL concentrations also were higher than preexposure levels following bar and restaurant visits [1.858 pg/mg creatinine higher (95% CI: 0.897, 3.758) and 0.615 pg/mg creatinine higher (95% CI: 0.210, 1.761), respectively], and were significantly different from changes after the control visits (p = 0.005).

CONCLUSION

Salivary cotinine and urinary NNAL increased significantly in nonsmokers after outdoor SHS exposure. Our findings indicate that such exposures may increase risks of health effects associated with tobacco carcinogens.

Reduced exercise tolerance and pulmonary capillary recruitment with remote secondhand smoke exposure

Rationale

Flight attendants who worked on commercial aircraft before the smoking ban in flights (pre-ban FAs) were exposed to high levels of secondhand smoke (SHS). We previously showed never-smoking pre-ban FAs to have reduced diffusing capacity (Dco) at rest.

Methods

To determine whether pre-ban FAs increase their Dco and pulmonary blood flow () during exercise, we administered a symptom-limited supine-posture progressively increasing cycle exercise test to determine the maximum work (watts) and oxygen uptake () achieved by FAs. After 30 min rest, we then measured Dco and at 20, 40, 60, and 80 percent of maximum observed work.

Results

The FAs with abnormal resting Dco achieved a lower level of maximum predicted work and compared to those with normal resting Dco (mean±SEM; 88.7±2.9 vs. 102.5±3.1%predicted ; p = 0.001). Exercise limitation was associated with the FAs' FEV₁ (r = 0.33; p = 0.003). The Dco increased less with exercise in those with abnormal resting Dco (mean±SEM: 1.36±0.16 vs. 1.90±0.16 ml/min/mmHg per 20% increase in predicted watts; p = 0.020), and amongst all FAs, the increase with exercise seemed to be incrementally lower in those with lower resting Dco. Exercise-induced increase in was not different in the two groups. However, the FAs with abnormal resting Dco had less augmentation of their Dco with increase in during exercise (mean±SEM: 0.93±0.06 vs. 1.47±0.09 ml/min/mmHg per L/min; p<0.0001). The Dco during exercise was inversely associated with years of exposure to SHS in those FAs with ≥10 years of pre-ban experience (r = −0.32; p = 0.032).

Conclusions

This cohort of never-smoking FAs with SHS exposure showed exercise limitation based on their resting Dco. Those with lower resting Dco had reduced pulmonary capillary recruitment. Exposure to SHS in the aircraft cabin seemed to be a predictor for lower Dco during exercise.

Exposure and kinetics of polycyclic aromatic hydrocarbons (PAHs) in cigarette smokers

Our study objectives were (1) to investigate the selectivity of polycyclic aromatic hydrocarbon (PAH) metabolites for tobacco smoke exposure and (2) to determine half-lives of PAH metabolites in smokers. There were 622 participants from the United States (US) and Poland, and of these, 70% were smokers. All subjects provided spot urine samples, and 125 smokers provided blood samples. Urinary PAH metabolite half-lives were determined in 8 smokers. In controlled hospital studies of 18 smokers, the associations between various measures of nicotine intake and urinary excretion of PAH metabolites were investigated. Plasma nicotine was measured by GC. LC-MS/MS was used to measure the plasma levels of cotinine and trans-3'-hydroxycotinine, and urine levels of nicotine and its metabolites, total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and PAH metabolites (2-naphthol, 1-, 2-, and 3-hydroxyfluorenes, 1-, 2-, 3-, and 4-hydroxyphenanthrenes, and 1-hydroxypyrene). Regardless of smoking status, PAH metabolite excretion was higher in Polish subjects than in US subjects (p-values <0.001). 1-Hydroxyfluorene exhibited the greatest difference between smokers and nonsmokers, with a 5-fold difference in Polish subjects and a 25-fold difference in US subjects, followed by 3- and 2-hydroxyfluorenes, 2-naphthol, and 1-hydroxypyrene. The differences for hydroxyphenanthrenes were small or nonsignificant. 1-Hydroxyfluorene had the highest correlation with urine nicotine equivalents (r = 0.77) and urine NNAL (r = 0.64). While the half-lives of PAH metabolites were <10 h in smokers, 1-hydroxyfluorene had the largest ratio of initial to terminal urine concentration (58.4 ± 38.6, mean ± SD) after smoking. Receiver Operating Characteristic (ROC) analysis of PAHs among Polish and US subjects further showed that hydroxyfluorenes are most highly discriminative of smokers from nonsmokers followed by 2-naphthol and 1-hydroxypyrene. In conclusion, hydroxyfluorenes, particularly 1-hydroxyfluorene, and 2-naphthol are more selective of tobacco smoke than 1-hydroxypyrene and hydroxyphenanthrenes. Characterization of hydroxyfluorene and 2-naphthol metabolites in urine may improve the characterization of PAHs from tobacco smoke and related disease risks among smokers and nonsmokers.

The ratio of a urinary tobacco-specific lung carcinogen metabolite to cotinine is significantly higher in passive than in active smokers

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol plus its glucuronides (total NNAL), metabolites of the lung carcinogen NNK, and total cotinine, metabolites of nicotine, are biomarkers of active and passive cigarette smoking. We calculated the total NNAL:total cotinine (×10(3)) ratio in 408 passive (infants, children, and adults) and 1088 active smokers. The weighted averages were 0.73 (95% confidence interval 0.71, 0.76) for passive smokers and 0.07 (0.06, 0.08) for active smokers (p < 0.0001). These results demonstrate that cotinine measurements may underestimate exposure of passive smokers to the lung carcinogen NNK in second-hand cigarette smoke. The total NNAL:total cotinine (×10(3)) ratio may provide an improved biomarker for evaluating the health effects of passive smoking.