Levels Of NNAL Research Articles

Urinary levels of cigarette smoke constituent metabolites are prospectively associated with lung cancer development in smokers.

Polycyclic aromatic hydrocarbons (PAH) are believed to be among the principal causative agents for lung cancer in smokers, but no epidemiologic studies have evaluated the relationship of PAH uptake and metabolism to lung cancer. In this study, we quantified prediagnostic urinary levels of r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene (PheT), a validated biomarker of PAH uptake and metabolism, as well as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronides (total NNAL), and cotinine and its glucuronides (total cotinine), validated biomarkers of uptake of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, and nicotine, respectively, in relation to lung cancer risk among current smokers in a nested case-control study within a cohort of 18,244 Chinese men in Shanghai, China. Urinary levels of PheT, total NNAL, and total cotinine were significantly higher in cases than controls (N = 476 matched pairs). ORs (95% confidence intervals) for lung cancer in the second, third, fourth, and fifth quintiles of PheT were 1.70 (1.00-2.88), 1.07 (0.62-1.84), 1.48 (0.86-2.53), and 2.34 (1.33-4.11), respectively, relative to the lowest quartile (P(trend) = 0.023) after adjustment for self-reported smoking intensity and duration and urinary total NNAL and total cotinine. This study also confirmed that urinary total NNAL and total cotinine are independently related to lung cancer risk.

Genetic variability in the metabolism of the tobacco‐specific nitrosamine 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone (NNK) to 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanol (NNAL)

Urinary metabolites of the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronides, termed total NNAL, have recently been shown to be good predictors of lung cancer risk, years before diagnosis. We sought to determine the contribution of several genetic polymorphisms to total NNAL output and inter-individual variability. The study subjects were derived from the Harvard/Massachusetts General Hospital Lung cancer case-control study. We analyzed 87 self-described smokers (35 lung cancer cases and 52 controls), with urine samples collected at time of diagnosis (1992-1996). We tested 82 tagging SNPs in 16 genes related to the metabolism of NNK to total NNAL. Using weighted case status least squares regression, we tested for the association of each SNP with square-root (sqrt) transformed total NNAL (pmol per mg creatinine), controlling for age, sex, sqrt packyears and sqrt nicotine (ng per mg creatinine). After a sqrt transformation, nicotine significantly predicted a 0.018 (0.014, 0.023) pmol/mg creatinine unit increase in total NNAL for every ng/mg creatinine increase in nicotine at p < 10E-16. Three HSD11B1 SNPs and AKR1C4 rs7083869 were significantly associated with decreasing total NNAL levels: HSD11B1 rs2235543 (p = 4.84E-08) and rs3753519 (p = 0.0017) passed multiple testing adjustment at FDR q = 1.13E-05 and 0.07 respectively, AKR1C4 rs7083869 (p = 0.019) did not, FDR q = 0.51. HSD11B1 and AKR1C4 enzymes are carbonyl reductases directly involved in the single step reduction of NNK to NNAL. The HSD11B1 SNPs may be correlated with the functional variant rs13306401 and the AKR1C4 SNP is correlated with the enzyme activity reducing variant rs17134592, L311V.

Metabolites of a Tobacco-Specific Lung Carcinogen in Children Exposed to Secondhand or Thirdhand Tobacco Smoke in Their Homes

People exposed to secondhand tobacco smoke (SHS) inhale the lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) which is metabolized to NNAL and its glucuroniders. These urinary metabolites, termed total NNAL, can be quantified. A related compound, iso-NNAL, has been proposed as a biomarker for exposure to smoke constituent residues on surfaces (thirdhand tobacco smoke). There is limited information in the literature on levels of total NNAL in children exposed to SHS. We recruited 79 parent--child dyads from homes where the enrolled parent was a cigarette smoker and visited their homes. Parents were asked questions, home ambient air quality was evaluated, and children provided urine samples. Urine was analyzed for total NNAL, total cotinine, total nicotine, and iso-NNAL. Ninety percent of the children had detectable total NNAL in urine; total nicotine and total cotinine were also detected in most samples. There were significant positive relationships between biomarker levels and exposure of children in the home. Levels were highest in homes with no smoking restrictions. African American children had significantly higher levels than other children. iso-NNAL was not detected in any urine sample. There was nearly universal exposure of children to the lung carcinogen NNK, due mainly to exposure to SHS from adult smokers in their homes. Homes with adult smokers should adopt restrictions to protect their children from exposure to a potent lung carcinogen.

Abstract 2758: Genetic variability in tobacco-specific nitrosamine NNK to NNAL metabolism

Abstract Introduction: Tobacco-specific nitrosamine (TSNA) NNK metabolites NNAL and NNAL-gluc) together, (total NNAL), have recently been shown to be good predictors of lung cancer risk, years prior to diagnosis. However, the inter-individual variability in the metabolism of NNK evaluated by the total NNAL output could be explained in part by genetic variability in the genes of NNK metabolism. We sought to determine the contribution of several genetic polymorphisms to total NNAL output by a regression analysis of NNAL levels on genotyping results, controlling for measures of smoking, age and sex. Methods: The study subjects were derived from the Harvard/ Massachusetts General Hospital Lung cancer case-control study. We selected 92 subjects (39 lung cancer cases and 53 controls) smokers at time of diagnosis and urine collection (1992-1996). We tested 77 tagging SNPs in 16 genes related to NNK to NNAL metabolism. Using case status as a mediator, we tested for the association of each SNP with square-root (sqrt) transformed NNAL (pmol per mg creatinine), controlling for age, sex, sqrt packyears and sqrt nicotine (ng per mg creatinine). Results: After a sqrt transformation, nicotine significantly predicted a 0.02 (0.015, 0.023) pmol/mg creatinine unit increase in NNAL for every ng/mg creatinine increase in nicotine at p = 2.85E-12. Three HSD11B1 SNPs, located in a 14kb region flanked by rs2235543 and rs3753519 in intron 1, were significantly associated with decreasing NNAL levels. Two of these SNPs, rs2235543 (p = 4.84E-08) and rs3753519 (p = 0.0017), passed multiple testing correction at FDR q value=1.07E-05 and 0.06 respectively. AKR1C4 rs7083869 G&amp;gt;A was also to be significantly associated with decreasing NNAL levels, p=0.019, FDR q=0.48. Conclusions: HSD11B1 and AKR1C4 enzymes are carbonyl reductases directly involved in the single step reduction of NNK to NNAL. The HSD11B1 SNPs may be correlated with the functional variant rs13306401 and the AKR1C4 SNP correlated with the enzyme activity reducing variant rs17134592, L311V. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2758. doi:10.1158/1538-7445.AM2011-2758

Environmental Tobacco Smoke Exposure Among Casino Dealers

This study quantified casino dealers' occupational exposure to environmental tobacco smoke (ETS). We measured casino dealers' exposure to ETS components by analyzing full-shift air and preshift and postshift urine samples. Casino dealers were exposed to nicotine, 4-vinyl pyridine, benzene, toluene, naphthalene, formaldehyde, acetaldehyde, solanesol, and respirable suspended particulates. Levels of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in urine increased significantly during an 8-hour work shift both with and without adjustment for creatinine clearance. Creatinine-unadjusted cotinine significantly increased during the 8-hour shift, but creatinine-adjusted cotinine did not increase significantly. Casino dealers at the three casinos were exposed to airborne ETS components and absorbed an ETS-specific component into their bodies, as demonstrated by detectable levels of urinary NNAL. The casinos should ban smoking on their premises and offer employee smoking cessation programs.

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

Cotinine is the most widely used biomarker to distinguish active versus passive smoking. However, there is an overlap in cotinine levels when comparing light or occasional smokers versus heavily exposed passive smokers. 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) is a tobacco-specific nitrosamine measurable in urine with a much longer half-life than cotinine. The aim of the study was to determine optimal cutoff points to discriminate active versus passive smokers and to compare sensitivity and specificity for the use of cotinine, NNAL, and the ratio of the NNAL/cotinine in urine. Cotinine and NNAL were measured in urine of 373 active smokers and 228 passive smokers. Geometric mean cotinine levels were 2.03 ng/ml (interquartile interval: 0.43-8.60) and 1,043 ng/ml (658-2,251) and NNAL levels were 5.80 pg/ml (2.28-15.4) and 165 pg/ml (90.8-360) pg/ml in passive and active smokers, respectively. NNAL/cotinine ratio in urine was significantly higher for passive smokers when compared with active smokers (2.85 vs. 0.16, p < .01). The receiver operating characteristics analysis determined optimal cutoff points to discriminate passive versus active smokers: 31.5 ng/ml for cotinine (sensitivity: 97.1% and specificity: 93.9%), 47.3 pg/ml for NNAL (87.4% and 96.5%), and 0.74 x 10⁻³ for NNAL/cotinine ratio (97.3% and 87.3%). Both urine cotinine and NNAL are sensitive and specific biomarkers for discriminating the source of tobacco smoke exposure. Cotinine is the best overall discriminator when biomarkers are measured while a person has ongoing exposure to tobacco smoke. NNAL because of its long half-life would be particularly useful when there is a delay between exposure and biomarker measurement. The NNAL/cotinine ratio provides similar sensitivity but poorer specificity at discriminating passive versus active smokers when compared with NNAL alone.

Measuring Tobacco Specific Lung Carcinogen among Nonsmoking Hospitality Workers in Richmond Virginia: A Preliminary Evaluation of Exposure before the Smoking Ban

The purpose of this pilot study is to measure the exposure to SHS among Richmond bar and restaurant workers and identify the prevalence of the tobacco-specific lung carcinogen-4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNAL) among nonsmoking bar and restaurants workers. Hair and urine samples were obtained from 40 nonsmoking bar and restaurant workers from Richmond establishments that do not have smoke free policies. Workers' exposure to SHS was estimated through measuring nicotine concentration in hair (NG/MG). Self-reported tobacco use was assessed in addition to performing urine analysis and listing sources and intensity of SHS exposure. Urine specimens were analyzed for total NNAL. Results Hair nicotine ranged from 0.05 to 42.15 ng/mg among workers with an average of 23.3 hours of self reported exposure in workplaces where smoking was permitted, indicating that workers in smoking restaurants and bars are exposed to SHS. Also, 60% of workers had a detectable level of NNAL that ranged from 0.019 to 1.9 PMol/ML. Increased levels of NNAL were mostly associated with the number of continuous hours of a single workplace exposure. In the city of Richmond, most bar and restaurant workers are continuously exposed to SHS in their workplace. To achieve complete protection for all workers and patrons in Richmond, Virginia, smoke free initiatives in all occupational settings are required. This information can be used to advocate for smoke free policies when discussing potential ways to strengthen the law.

Abstract B89: Child second-hand and third-hand exposure to carcinogens and tobacco toxicants

Abstract Exposure to secondhand tobacco smoke (SHS) is a recognized cause of cardiovascular disease and cancer in adults and respiratory disease in children. In spite of this, approximately one-third of children in the United States live in a home where cigarette smoking is permitted. Few limitations have been enacted on the primary source of SHS exposure in children, inhome exposure. We quantified 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucoronidies (total NNAL) in the urine of 79 children who lived in homes with a parent(s) who smoked. Total NNAL is an accepted biomarker of uptake of the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone. Cotinine and nicotine and their glucuronides (total cotinine/nicotine) were also quantified. Children ranged in age from one month to 10 years (mean+ sd: 3.82+2.55); 49% were male. Among the parents, 56% were African American, 26% had &amp;lt; high school education, 67% were unemployed and 76% had a monthly income &amp;lt;$1800. Average number of cigarettes smoked per day (CPD) was 9.5+5.3; 64% reported smoking their first cigarette within 30 minutes of waking and average number of smokers living in home was 1.9+.96. 72% of parents reported that their child had been exposed to SHS in past week and 70.9% reported at least some home smoking bans in their home. Geometric mean levels of total NNAL were 0.08 pmol/mL (95% CI:0.06 — 0.10). Total cotinine and total nicotine 11.88 ng/mL (95% CI:8.42 — 16.77) and 6.90 ng/mL (95% CI:4.57 — 10.43), respectively. There were strong and significant correlations among all three biomarkers (.64 -.96, p&amp;lt;.001). Detectable total NNAL, cotinine and nicotine were found in 90%, 95% and 90% of children, respectively. Total NNAL was significantly different across: 1) ethnic groups (i.e., African American children &amp;gt; White and “Other” [.11, 95% CI:.08-.17 vs. .03, 95% CI:.02-.06 vs. .07, 95% CI: .03-.12, respectively], p&amp;lt;.01; 2) parental employment (i.e., children of unemployed parents &amp;gt; employed [i.e., .10, 95% CI:.07 — .14 vs. .05, 95% CI .03 — .05] p&amp;lt;.05) and 3) monthly income (i.e., lower income &amp;gt; higher income [.09, 95% CI .07 — .13 vs. .04, 95% CI: .02 — .09], p&amp;lt;.052). Nicotine and cotinine followed similar trends. Total NNAL was significantly different by parent level of nicotine dependence (&amp;lt; 30 minutes to first cigarette vs. &amp;gt; 30 minutes); parental endorsement of child exposure in home; and levels of home and car smoking restrictions. NNAL was also correlated with parent CO level (r=.29, p&amp;lt;.05); air quality (r=.28, p&amp;lt;.05); number of smokers residing in home (r=.23, p&amp;lt;.01); and CPD in home (r=.30, p&amp;lt;.01). Similar trends were observed in cotinine and nicotine. Although child age was not significantly correlated with NNAL or cotinine, a significant negative association was found for nicotine (r =-.27, p&amp;lt;.05), with younger age associated with higher nicotine values. Detection of NNAL but not iso-NNAL in our analyses indicates that the great majority of exposure is due to secondhand smoke exposure (via air) rather than thirdhand exposure (e.g. via residues on furniture, carpets). Our results suggest that children living with a smoking parent are exposed to detectable levels of carcinogens and nicotine. Interventions need to be designed to dramatically lower, or ideally eliminate, exposure to home SHS. Citation Information: Cancer Prev Res 2010;3(12 Suppl):B89.

Urine Cotinine Underestimates Exposure to the Tobacco-Derived Lung Carcinogen 4-(Methylnitrosamino)-1-(3-Pyridyl)-1-Butanone in Passive Compared with Active Smokers

Cotinine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) are widely used biomarkers for tobacco-derived nicotine and the lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), respectively. The discrepancy between cotinine levels in relation to disease risk comparing active versus passive smoking suggests a nonlinear tobacco smoke dose-response and/or that cotinine is not providing an accurate measure of exposure to the toxic constituents of secondhand tobacco smoke. Cotinine and NNAL were measured in the urine of 373 active smokers and 228 passive smokers. Average cotinine levels were 1,155 (interquartile range, 703-2,715) for active smokers and 1.82 (0.45-7.33) ng/mg creatinine for passive smokers. Average NNAL levels were 183 (103-393) and 5.19 (2.04-11.6) pg/mg creatinine, respectively. NNAL/cotinine ratio in urine was significantly higher for passive smokers when compared with active smokers (2.85 × 10(3) versus 0.16 × 10(3), P < 0.0001). Passive smoking is associated with a much higher ratio of NNAL/cotinine in the urine compared with active smoking. Cotinine measurement leads to an underestimation of exposure to the carcinogen NNK from secondhand smoke when compared with active smoking.

UGT2B17 유전자의 deletion polymorphism과 폐암과의 연관성

Glucuronidation은 NNAL [4-(methylnitrosamno)-1-(3-pyridyl)-1-butanol]의 주요 pathway이며, UGT2B의 family인 UGT2B17 (UGT, uridine diphospho-glucuronosyltransferase) 유전자는 발암원의 glucuronidation에 관여 한다. UGT2B17 결손은 NNAL의 감소 수준과 특정 암에 있어 위험도를 증가시킨다. UGT2B17 유전자의 copy 수는 사람에서 개인별로 0~2로 다양하다. 본 연구에서는 UGT2B17 결손이 폐암의 위험도와 연관성을 가지는 가를 알아보기 위해 한국인인 271명의 대조군과 176명의 폐암환자의 샘플로 PCR 방법으로 CNV를 조사하였다. 그 결과, 현재까지 보고된 백인과 흑인에 비해 한국인에서 결실 대립형질이 현저히 높게 나타났다. 백인에서 유전자 두 개 모두가 결실된 0 copy 수가 약 10%를 나타낸 것에 비해, 본 연구의 한국인에서는 0 copy 수가 약 74%를 나타내었다. 더욱이 양 쪽 결실이 여성그룹에서 전반적으로 남성그룹에 비해 높게 나타났다. 그러나 UGT2B17 유전자가 CNV와 폐암과의 연관성은 찾을 수 없었다. 이러한 결과는 UGT2B17 유전자의 결실이 폐암의 감수성과는 연관되어 있지 않으나, UGT2B17 CNV 다형성이 인종간의 진화적 분석의 유용한 마커로 사용이 가능할 것으로 사료된다. Glucuronidation is a major pathway for NNAL [4-(methylnitrosamno)-1-(3-pyridyl)-1-butanol] and UGT2B17 (UGT, uridine diphospho-glucuronosyltransferase) is from the UGT2B family that glucuronidates carcinogens. UGT2B17 deletion was associated with decreased levels of NNAL and with increased risk of some cancers. The UGT2B17 gene varies in copy number from zero to two per individual in humans. To examine whether UGT2B17 gene deletion is associated with the risk of lung cancer, we investigated copy number variants (CNV) in 271 cancer-free controls and 176 cases of lung cancer in Koreans by a PCR-based method. The frequency of the UGT2B17 deleted alleles was much higher than in other Caucasian and African-American groups which have already been reported. While only up to 10% of Caucasians have zero copies of the gene, up to 74% of Koreans in this study showed that both copies of the gene were deleted. Furthermore, the overall frequency of this dual deletion in female groups was higher than in male groups. However, there was no association between CNV in UGT2B17 and lung cancer. This result suggested that the UGT2B17 deletion allele was not associated with the susceptibility of lung cancers in the Korean group. However, this UGT2B17 CNV polymorphism may be a useful marker for evolutionary analysis among races.

Abstract 2824: A prospective evaluation of dietary indole-3-carbinol in relation to risk of lung cancer in the Singapore Chinese Health Study

Abstract Background: Indole-3-carbinol (I3C) is a naturally occurring hydrolysis product of glucobrassicin, a glucosinolate found in cruciferous vegetables. I3C has been shown to inhibit carcinogen-induced occurrence of cancer in multiple organs including lung in experimental animals. High consumption of dietary glucobrassicins was inversely related to urinary levels of NNAL, a metabolite of the tobacco-specific lung carcinogen NNK. Data on the dietary intake of I3C or its precursors and lung cancer risk in humans are lacking. Methods: We prospectively examined the association between dietary intake of glucobrassicins and risk of lung cancer in the Singapore Chinese Health Study, a cohort of 63,257 middle-aged and older Chinese men and women enrolled between 1993 and 1998. Dietary intake of glucobrassicins was derived from a validated, semi-quantitative food-frequency questionnaire administered to subjects in person at enrollment and the quantified amount of glucobrassicin in specific cruciferous vegetables purchased from Singapore markets. We had complete follow-up for incidence of cancer and death among cohort participants through computer record linkage analysis to the nation-wide Singapore cancer and death registries. As of December 31, 2007, 1,104 incident cases of lung cancer were identified within the cohort. Cox proportional hazards regression was used to evaluate the association between dietary intake of glucobrassicins and lung cancer risk. The regression model included age, body mass index (kg/m2), year of interview, gender, dialect group, level of education, smoking status, number of cigarettes/day and years of cigarette smoking, dietary intake of beta-cryptoxanthin, and total calorie intake. Results: After adjustment for number of cigarettes/day, number of years of smoking and other potential confounders, current smokers with high intake of glucobrassicins had a borderline statistically significant reduced risk of lung cancer (Ptrend=0.08). Compared to the lowest quartile, hazard ratios (HR) [95% confidence intervals (CI)] for the 2nd, 3rd, and 4th quartile of glucobrassicins were 0.94 (0.77-1.15), 0.95 (0.76-1.18) and 0.77 (0.59-0.99), respectively. This inverse association was more evident after excluding the first 5-years of follow-up; the corresponding HR (95% CI) were 0.89 (0.70-1.14), 0.93 (0.72-1.21) and 0.61 (0.44-0.85) (Ptrend=0.01). The present study did not show an inverse association between dietary isothiocyanate (ITC) intake and lung cancer in current smokers. Neither I3C precursors nor ITC was related to risk of lung cancer in never or former smokers. Conclusion: High intake of dietary glucobrassicins was associated with reduced incidence of lung cancer in smokers. The findings of this study suggest that I3C precursors rather than ITC present in cruciferous vegetables may exert a protective role in the development of lung cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2824.

Evaluating oral noncombustible potential-reduced exposure products for smokers

Potential-reduced exposure products (PREPs) are marketed as a way for smokers to continue using tobacco while possibly lessening their tobacco toxicant intake. Some tobacco-based PREPs are combustible and intended to be smoked, while others are noncombustible and intended to be administered orally (e.g., Camel Snus [CS] tobacco sachets and Ariva tobacco tablets). The ability of these noncombustible PREPs to reduce smokers' exposure to cigarette-delivered toxicants and suppress tobacco abstinence symptoms effectively is unclear. Clinical laboratory methods have been used to measure combustible PREP-associated toxicant exposure and abstinence symptom suppression and could be applied to evaluating the effects of orally administered noncombustible PREPs. In this study, 21 smokers (6 women) participated in four 5-day conditions that differed by product used: CS, Ariva, own brand cigarettes, or no tobacco. Measures included expired-air carbon monoxide (CO), the urinary metabolite of nicotine (cotinine), the urinary metabolite of the carcinogen NNK (NNAL-T), and subjective effect ratings. Relative to own brand, all other conditions were associated with CO and cotinine levels that were lower and abstinence symptom ratings that were greater. Only no-tobacco use was associated with significantly lower NNAL levels. Acceptability ratings were also lower in all conditions relative to own brand. Although these oral products reduce exposure to CO, their ineffective abstinence symptom suppression and low acceptability may limit their viability as PREPs. As with combustible PREPs, clinical laboratory study of orally administered noncombustible PREPs will be a valuable part of any comprehensive PREP evaluation strategy.

Elimination Kinetics of the Tobacco-Specific Biomarker and Lung Carcinogen 4-(Methylnitrosamino)-1-(3-Pyridyl)-1-Butanol

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) is tobacco specific and has a longer half-life than other tobacco biomarkers studied thus far. An accurate measurement of the NNAL half-life is important for optimal use to assess exposure to tobacco smoke. We determined the half-life of NNAL in urine in eight daily smokers on a clinical research ward and in five occasional smokers in a real-life environment. Total NNAL in urine was monitored for 14 days in daily smokers after stopping smoking and for up to 60 days in occasional smokers. The average half-life for the terminal phase in the daily smoker group using a two-compartmental body model was 10.3 days (beta phase), and using a noncompartmental model, it was 9.1 days. In the occasional group, these values were 17.6 and 16.0 days, respectively. The alpha-phase half-lives were 14.3 and 27.8 hours for the two groups, respectively. The inter-subject coefficient of variation of the NNAL terminal half-life ranged from 14% to 30%, and the intra-subject coefficient of variation ranged from 3% to 18%. There was very good agreement between the plasma and urinary half-lives in two subjects with plasma analyses: 7.4 versus 7.9 days and 9.2 versus 10.7 days. Mean renal clearance of NNAL was 13 +/- 2.3 mL/min. The terminal half-life of NNAL of 10 to 18 days indicates that this biomarker can be used to detect tobacco smoke exposure for 6 to 12 weeks after cessation of exposure and requires a similar time to assess the steady levels of NNAL after switching from one tobacco product to another.

Urinary levels of tobacco-specific nitrosamine metabolites in relation to lung cancer development in two prospective cohorts of cigarette smokers.

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronides (sum of which is denoted as total NNAL) are metabolites of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). NNK and NNAL can induce lung cancer in laboratory animals but human data are limited. The association between prediagnostic levels of urinary total NNAL and risk of lung cancer development was evaluated in two prospective cohorts of Chinese cigarette smokers. We conducted a nested case-control study involving 246 cases of incident lung cancer and 245 cohort controls who were individually matched to the index cases by age, gender, neighborhood of residence at cohort enrollment, and date of urine collection. Urinary levels of total NNAL were significantly associated with risk of lung cancer in a dose-dependent manner. Relative to the lowest tertile, risks associated with the second and third tertiles of total NNAL were 1.43 [95% confidence interval (95% CI), 0.86-2.37] and 2.11 (95% CI, 1.25-3.54), respectively (P for trend=0.005) after adjustment for self-reported smoking history and urinary total cotinine. Smokers in the highest tertiles of urinary total NNAL and total cotinine exhibited a 8.5-fold (95% CI, 3.7-19.5) increased risk for lung cancer relative to smokers with comparable smoking history but possessing the lowest tertiles of urinary total NNAL and total cotinine. Findings of the present study directly link NNK exposure to lung cancer development in humans.

Correlation between the Urine Profile of 4-(Methylnitrosamino)-1-(3-Pyridyl)-1-Butanone Metabolites and N7-Methylguanine in Urothelial Carcinoma Patients

A major carcinogen, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), is present in cigarette smoke and its metabolite, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), is used as an exposure biomarker for environmental tobacco smoke (ETS). This metabolite (NNAL) can be either detoxified into glucuronidated NNAL (NNAL-Gluc) or activated into an unstable reactive metabolite that methylates DNA along with formation of 4-hydroxy-4-(3-pyridyl)-butyric acid [hydroxy acid (HA)]. Therefore, the carcinogenic risk associated with ETS exposure is greatly modulated by individual variations in metabolic activation and detoxification capabilities. In this study, we defined the urinary HA/total NNAL [HA/total NNAL] ratio as the activation index and NNAL-Gluc/free NNAL [(total NNAL-free NNAL)/free NNAL] ratio as the detoxification index of NNK. The major methylated DNA adduct N(7)-methylguanine (N(7)-MeG), considered as the carcinogenic biomarker for cigarette smoking, was excreted in urine. The objective of this study was to investigate the effects of these metabolic indexes of NNK on N(7)-MeG urinary excretion in a population of urothelial carcinoma patients. Urinary levels of total NNAL (free NNAL plus NNAL-Gluc), free NNAL, HA, and N(7)-MeG were positively correlated with smoking. Furthermore, activation index and detoxification index correlated positively and negatively with N(7)-MeG levels, respectively. Our results suggest that these metabolic indices may represent the phenotype of individual metabolism capability and modulate the carcinogenic risk of ETS exposure.

Exposure to a Tobacco-Specific Lung Carcinogen in Adolescent versus Adult Smokers

Previous studies with adult smokers have shown an association between number of cigarettes smoked per day (CPD) and levels of biomarkers of exposure to the tobacco-specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). This study compared carcinogen and nicotine exposure in adolescent and adult smokers across categories of CPD. Baseline smoking history and biomarker data were merged from six studies to make two samples: one of adolescent smokers and one of adult smokers. Metabolites of NNK, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), and its glucuronides (NNAL-Gluc) and total cotinine were quantified in urine. CPD was stratified into categories of 5 to 10, 11 to 15, and 16 to 20 CPD. Adolescents tended to have lower mean levels of NNAL plus NNAL-Glucs (total NNAL) compared with adults, although differences were not significant overall. Adolescent mean levels of NNAL/CPD were significantly lower than adult levels only in the 11 to 15 CPD category (P = 0.045). However, a significant positive relationship was observed for total NNAL/CPD by age. No significant differences between adolescents and adults were found in mean levels of total cotinine or cotinine/CPD. A subsample of urines from adolescents and adults were analyzed for NNAL-Glucs and NNAL. Adolescents and adults did not significantly differ in the ratio of NNAL-Glucs to NNAL. Adolescent uptake of NNK and nicotine tends to be lower although not statistically different from adults. The lack of significant differences may be due to the wide variation in exposure in adolescents. Some adolescent smokers are exposed to lung carcinogens at levels similar to those of adults.

Abstract B46: Evaluation of biomarkers of exposure to selected smoke constituents in adult cigarette smokers using unidentified Marlboro Snus.

Abstract B46 Introduction It has been recently suggested in literature that adult smokers may be considering smokeless tobacco products (STP) as an alternative to smoking. While there are several STP available commercially, there is significant interest in tobacco pouch products (referred to as Snus), similar to those available in Sweden. There are few studies that have systematically investigated the changes in exposure when adult smokers use such products. Therefore, this study was conducted with the objective to evaluate the change in exposure in adult smokers who use unidentified Marlboro Snus (MS). Methods: A randomized, controlled, open-label study was conducted in which 120 adult smokers were randomized into one of the groups; CS - subjects (n=30) continue smoking their own brand, DU - subjects (n=60) reduced their normal daily cigarette consumption by ≥ 50% and were allowed to use MS (~0.3 g tobacco in a pouch, ~4 mg nicotine in tobacco) in test market in June 2007, ExclSn- subjects (n=15) stopped smoking their cigarettes but were allowed to use MS, StopTob- Subjects (n=15) were not allowed to use any tobacco products for the entire duration of the eight day study. Biomarkers of exposure measured at Baseline (Days -2 and -1) and Days 7 and 8 were 24 hr urinary excretion of the N-nitrosamines (total NNAL and total NNN), nicotine (estimated as nicotine equivalents - NE), o-toluidine (OT), 2-aminonaphthalene (2-AN), 4-aminobiphenyl (4-ABP), S-phenyl mercapturic acid (S-PMA), 3-hydroxy benzo[a]pyrene (3-OH BaP) and urine mutagenicity; plasma nicotine, cotinine, trans-3’hydroxycotinine, and blood carboxyhemoglobin (COHb) were also measured at various time points. Results Statistically significant (p &amp;lt; 0.05) reductions in post-baseline 24-hr urinary levels of NNAL, NNN, NE, OT, 2-AN, 4-ABP, S-PMA, 3-OH BaP, urine mutagenicity and COHb were observed in adult smokers in the DU group compared to CS. After correcting for the residual effect, using the biomarker levels in the StopTob Group, a proportionate ~50% reduction in most of the biomarkers (except for urinary NE ~36%, OT ~24%, and COHb ~ 29%) were observed. The overall average MS consumption in the DU group was 2.6 pouches/day with a residence time of 54.3 minutes. Adult smokers in the ExclSn group manifested an even larger reduction in all the urinary and blood biomarkers of exposure when compared to those in the DU group. These reductions in the ExclSn Group were similar (p&amp;gt;0.05) to that observed for the StopTob Group for all the biomarkers of exposure except urinary NNN (-81%), NNAL (-62%), and nicotine equivalents(-71%). MS consumption was 4 pouches/day and the average residence time was 49.4 minutes in the ExclSn group. Conclusion It can be concluded from this study that there is minimal contribution to exposure from MS in the dual usage group when adult smokers reduce the number of cigarettes by &amp;gt; 50% and chose to use MS under the consumption patterns observed in this study. The adult smokers sustained a substantial reduction in exposure when exclusively using MS. Citation Information: Cancer Prev Res 2008;1(7 Suppl):B46.

Potential reduced exposure products (PREPs) for smokeless tobacco users: Clinical evaluation methodology

Several potential reduced exposure products (PREPs) for smokeless tobacco (SLT) users are marketed in the United States, though their effects are largely unknown. These products include some that are low in tobacco-specific nitrosamines (TSNs), like Stonewall, a pressed tobacco tablet, and General snus, a moist snuff product produced in Sweden. Methodology assessing the toxicant exposure and effects of cigarette-like PREPs for smokers has been developed, and might be modified for use in evaluating PREPs for SLT users. This report describes two studies examining the toxicant exposure and effects of two PREPs for SLT users. Study 1 (n = 13) consisted of four 4.5-hr laboratory sessions where SLT products (own brand, Stonewall, General snus, and tobacco-free placebo) were used for four 30-min episodes and nicotine exposure and tobacco/nicotine abstinence symptoms were measured. Study 2 (n = 19) consisted of four 5-day ad libitum use periods when participants used own brand, Stonewall, General snus, or no SLT and urinary levels of metabolites of nicotine (cotinine) and the TSN 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNAL) and abstinence symptoms were measured. Compared with own brand, Stonewall was associated with lower levels of cotinine and NNAL, while General snus was associated with similar levels of cotinine and lower levels of NNAL. Abstinence symptoms generally did not differ across tobacco conditions. These results show that clinical laboratory methods can be used to evaluate the toxicant exposure and abstinence symptom suppression associated with PREPs for SLT users.

Exposure to nicotine and a tobacco-specific carcinogen increase with duration of use of smokeless tobacco

Background:Smokeless tobacco is an efficient delivery vehicle for nicotine and can contain significant amounts of carcinogens. However, few studies have examined factors that might moderate levels of nicotine or carcinogen...

Smoking reduction fails to improve clinical and biological markers of cardiac disease: A randomized controlled trial

Cigarette reduction has been proposed as a treatment goal for smokers who are not interested in stopping completely. This randomized controlled trial was designed to determine the effect of a smoking reduction intervention on smoking behavior, symptoms of heart disease, and biomarkers of tobacco exposure. It included 152 patients with heart disease who did not intend to stop smoking in the next 30 days. Participants were randomly assigned to smoking reduction (SR) or usual care (UC). SR subjects received counseling and nicotine replacement therapy to encourage > or =50% reduction in cigarettes per day (CPD). They were followed at 1, 3, 6, 12 and 18 months to assess smoking, heart disease symptoms, quality of life and nicotine, cotinine, carbon monoxide (CO), white blood cell (WBC) count, fibrinogen, hs-C-reactive protein (hs-CRP), F2-isoprostane, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronides (total NNAL), and 1-hydroxypyrene (1-HOP). At 6 months SR participants reduced by 10.9 CPD, compared with 7.4 CPD in UC (difference NS). At 18 months, 9/78 SR vs. 9/74 UC participants quit smoking. There were no significant differences between treatment groups in angina, quality of life or adverse events, nicotine, cotinine, CO, WBC count, fibrinogen, hs-CRP, F2-isoprostane, total NNAL or 1-HOP levels at any time point. To determine if smoking reduction, regardless of treatment condition, was associated with improved outcomes, we compared all subjects at 6 months to baseline (mean reduction in CPD from 27.4 to 18.1, p<.01). There were no significant changes in outcome variables except CO, which decreased by 5.5 ppm (p<.01). There were also no significant improvements considering only subjects who reduced by > or =50%, or those who had no history of reduction prior to enrollment in the study. The SR intervention did not significantly reduce CPD or toxin exposure, or improve smoking cessation or clinical outcomes compared to UC. These results emphasize the importance of abstinence for smokers with heart disease to minimize health risks from tobacco.