Last data update: Jun 03, 2024. (Total: 46935 publications since 2009)
Records 1-15 (of 15 Records) |
Query Trace: Ashley DL [original query] |
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Influence of half-life and smoking/nonsmoking ratio on biomarker consistency between Waves 1 and 2 of the Population Assessment of Tobacco and Health Study
Ashley DL , Zhu W , Bhandari D , Wang L , Feng J , Wang Y , Meng L , Xia B , Jarrett JM , Chang CM , Kimmel HL , Blount BC . Cancer Epidemiol Biomarkers Prev 2023 33 (1) 80-87 BACKGROUND: Biomarkers of exposure are tools for understanding the impact of tobacco use on health outcomes if confounders like demographics, use behavior, biological half-life and other sources of exposure are accounted for in the analysis. METHODS: We performed multiple regression analysis of longitudinal measures of urinary biomarkers of alkaloids, tobacco-specific nitrosamines, polycyclic aromatic hydrocarbons, volatile organic compounds (VOC), and metals to examine the sample-to-sample consistency in Waves 1 and 2 of the Population Assessment of Tobacco and Health Study including demographic characteristics and use behavior variables of persons who smoked exclusively. Regression coefficients, within- and between-person variance, and intra-class correlation coefficients were compared to biomarker smoking-nonsmoking population mean ratios and biological half-lives. RESULTS: Most biomarkers were similarly associated with sex, age, race/ethnicity, and product use behavior. The biomarkers with larger smoking-nonsmoking population mean ratios had greater regression coefficients related to recency of exposure. For VOC and alkaloid metabolites, longer biological half-life was associated with lower within-person variance. For each chemical class studied, there were biomarkers that demonstrated good intra-class correlation coefficients. CONCLUSIONS: For most of the biomarkers of exposure reported in the PATH Study, for people who smoke cigarettes exclusively, associations are similar between urinary biomarkers of exposure and demographic and use behavior covariates. Biomarkers of exposure within-subject consistency is likely associated with non-tobacco sources of exposure and biological half-life. IMPACT: Biomarkers measured in the PATH Study provide consistent sample-to-sample measures from which to investigate the association of adverse health outcomes with the characteristics of cigarettes and their use. |
Mouth level intake of nicotine from three brands of little filtered cigars with widely differing product characteristics among adult consumers
Ashley DL , Zhu W , Watson CH , Bravo R , Ngac PK , Valentin-Blasini L , Pickworth WB , Kurti AN , Cunningham C , Blount BC . Chem Res Toxicol 2023 36 (1) 43-52 Little filtered cigars are tobacco products with many cigarette-like characteristics. However, despite cigars falling under the U.S. Food and Drug Administration regulatory authority, characterizing flavors, which are still allowed in little filtered cigars, and filter design may influence how people use the products and the resulting exposure to harmful and potentially harmful constituents. We estimated nicotine mouth level intake (MLI) from analyses of little cigar filter butt solanesol levels, brand characteristics, carbon monoxide boost, and puff volume in 48 dual cigarette/cigar users during two repeat bouts of ad lib smoking of three little filtered cigar brands. Mean nicotine MLI for the three brands was significantly different with Swisher Sweets (0.1% ventilation) Cherry at 1.20 mg nicotine, Cheyenne Menthol (1.5%) at 0.63 mg, and Santa Fe unflavored (49%) at 0.94 mg. The association between nicotine MLI and puff volume was the same between Cheyenne Menthol and Santa Fe unflavored. However, these were different from Swisher Sweets Cherry. At least five main factors─flavor, ventilation, filter design, nicotine delivery related to tar, and user puff volume─may directly or indirectly impact MLI and its association with other measures. We found that users of little filtered cigars that have different filter ventilation and flavor draw dissimilar amounts of nicotine from the product, which may be accompanied by differences in exposure to other harmful smoke constituents. |
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
Ashley DL , Zhu W , Wang L , Sosnoff C , Feng J , Del Valle-Pinero AY , Cheng YC , Chang CM , van Bemmel D , Borek N , Kimmel HL , Silveira ML , Blount BC . Nicotine Tob Res 2022 25 (4) 616-623 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. |
Urinary acrylonitrile metabolite concentrations before and after smoked, vaporized, and oral cannabis in frequent and occasional cannabis users
Ashley DL , De Jesús VR , Abulseoud OA , Huestis MA , Milan DF , Blount BC . Int J Environ Res Public Health 2020 17 (18) Cannabis use through smoking, vaping, or ingestion is increasing, but only limited studies have investigated the resulting exposure to harmful chemicals. N-acetyl-S-(2-cyanoethyl)-L-cysteine (2CYEMA), a urinary metabolite of acrylonitrile, a possible carcinogen, is elevated in the urine of past-30-day cannabis users compared to non-cannabis users. Five frequent and five occasional cannabis users smoked and vaped cannabis on separate days; one also consumed cannabis orally. Urine samples were collected before and up to 72 h post dose and urinary 2CYEMA was quantified. We compared 2CYEMA pre-exposure levels, maximum concentration, time at maximum concentration for occasional versus frequent users following different exposure routes, and measured half-life of elimination. Smoking cannabis joints rapidly (within 10 min) increased 2CYEMA in the urine of occasional cannabis users, but not in frequent users. Urine 2CYEMA did not consistently increase following vaping or ingestion in either study group. Cigarette smokers had high pre-exposure concentrations of 2CYEMA. Following cannabis smoking, the half-lives of 2CYEMA ranged from 2.5 to 9.0 h. 2CYEMA is an effective biomarker of cannabis smoke exposure, including smoke from a single cannabis joint, however, not from vaping or when consumed orally. When using 2CYEMA to evaluate exposure in cannabis users, investigators should collect the details about tobacco smoking, route of consumption, and time since last use as possible covariates. |
Methyl tertiary-butyl ether exposure from gasoline in the U.S. population, NHANES 2001-2012
Silva LK , Espenship MF , Pine BN , Ashley DL , De Jesus VR , Blount BC . Environ Health Perspect 2019 127 (12) 127003 BACKGROUND: Methyl tertiary-butyl ether (MTBE) was used as a gasoline additive in the United States during 1995-2006. Because of concerns about potential exposure and health effects, some U.S. states began banning MTBE use in 2002, leading to a nationwide phaseout in 2006. OBJECTIVES: We investigated the change in blood MTBE that occurred during the years in which MTBE was being phased out of gasoline. METHODS: We used data from the National Health and Nutrition Examination Survey (NHANES) from 2001-2012 to assess the change in blood MTBE over this period. We fit sample-weighted multivariate linear regression models to 12,597 human blood MTBE concentrations from the NHANES 2001-2002 to 2011-2012 survey cycles. RESULTS: The unweighted proportion of the individuals with MTBE blood levels above the limit of detection (LOD) of 1.4 ng/L was 93.9% for 2001-2002. This portion dropped to 25.4% for the period 2011-2012. Weighted blood MTBE median levels (ng/L) (25th and 75th percentiles) decreased from 25.8 (6.08, 68.1) ng/L for the period from 2001-2002 to 4.57 (1.44, 19.1) ng/L for the period from 2005-2006. For the entire postban period (2007-2012), MTBE median levels were below the detection limit of 1.4 ng/L. DISCUSSION: These decreases in blood MTBE coincided with multiple statewide bans that began in 2002 and a nationwide ban in 2006. The multivariate log-linear regression model for the NHANES 2003-2004 data showed significantly higher blood MTBE concentrations in the group who pumped gasoline less than 7 h before questionnaire administration compared to those who pumped gasoline more than 12 h before questionnaire administration (p=0.032). This study is the first large-scale, national-level confirmation of substantial decrease in blood MTBE levels in the general population following the phaseout of the use of MTBE as a fuel additive. https://doi.org/10.1289/EHP5572. |
Chemical characterization of domestic oral tobacco products: total nicotine, pH, unprotonated nicotine and tobacco-specific N-nitrosamines
Lawler TS , Stanfill SB , Zhang L , Ashley DL , Watson CH . Food Chem Toxicol 2013 57 380-6 In the United States, moist snuff has been studied more widely than other distinct categories of oral tobacco. In this study, we measured pH, moisture, nicotine (total and unprotonated), and tobacco-specific N-nitrosamines (TSNAs) for other established (twist, loose leaf, plug, and dry snuff without pouch) and emerging oral tobacco products (dry snuff pouch, US-made snus, and dissolvable tobacco). Among the seven product categories, product pH ranged from 4.7 to 7.9, and total nicotine concentration spanned from 3.9 to 40.1mg/g. The most readily absorbable form of nicotine (unprotonated nicotine) varied more than 350-fold, ranging from 0.01 to 3.7mg/g. While the highest total nicotine concentrations were observed in twist products, snus and dissolvable tobacco had the highest unprotonated nicotine levels. Among all products, total TSNA concentrations ranged from 313 to 76,500ng/g with dry snuff having the highest total TSNA concentrations. This study demonstrates the diversity among oral tobacco products and highlights the potential of these products to deliver a wide range of nicotine and carcinogenic TSNAs. Characterizing the chemical content of these products may be helpful in further understanding the risk of marketing these products to oral tobacco users and smokers as an alternative and discrete form of tobacco. |
Chemical analysis of Alaskan iq'mik smokeless tobacco
Hearn BA , Renner CC , Ding YS , Vaughan-Watson C , Stanfill SB , Zhang L , Polzin GM , Ashley DL , Watson CH . Nicotine Tob Res 2013 15 (7) 1283-8 INTRODUCTION: Iq'mik, a form of smokeless tobacco (ST), is traditionally used by Cup'ik and Yup'ik Eskimo people of western Alaska. Iq'mik is sometimes incorrectly considered to be a healthier alternative to smoking because its ingredients are perceived as "natural." Our chemical characterization of iq'mik shows that iq'mik is not a safe alternative to smoking or other ST use. METHODS: We measured nicotine and pH levels of tobacco and ash used to prepare iq'mik. We also characterized levels of toxins which are known to be present in ST including tobacco-specific nitrosamines (TSNAs) and polycyclic aromatic hydrocarbons (PAHs) using chromatographic separations coupled with isotope dilution mass spectrometry. RESULTS: Nicotine content in the iq'mik tobacco was very high, ranging from 35 to 43mg/g, with a mean of 39mg/g. The pH of the iq'mik tobacco-ash mixture was 11, an extremely high level compared with most ST products. High levels of PAHs were seen in the fire-cured tobacco samples with a benzo[a]pyrene level of 87ng/g. Average TSNA levels in the tobacco were 34, 2,700, and 340ng/g for 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), N'-nitrosonornicotine (NNN), and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), respectively. CONCLUSIONS: Iq'mik contains high levels of the more easily absorbed unionized nicotine as well as known carcinogenic TSNAs and PAHs. The perception that iq'mik is less hazardous than other tobacco products due to the use of "natural" ingredients is not warranted. This chemical characterization of iq'mik gives a better understanding of the risk of possible adverse health effects of its use. |
Simultaneous analysis of 28 urinary VOC metabolites using ultra high performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI/MSMS)
Alwis KU , Blount BC , Britt AS , Patel D , Ashley DL . Anal Chim Acta 2012 750 152-60 Volatile organic compounds (VOCs) are ubiquitous in the environment, originating from many different natural and anthropogenic sources, including tobacco smoke. Long-term exposure to certain VOCs may increase the risk for cancer, birth defects, and neurocognitive impairment. Therefore, VOC exposure is an area of significant public health concern. Urinary VOC metabolites are useful biomarkers for assessing VOC exposure because of non-invasiveness of sampling and longer physiological half-lives of urinary metabolites compared with VOCs in blood and breath. We developed a method using reversed-phase ultra high performance liquid chromatography (UPLC) coupled with electrospray ionization tandem mass spectrometry (ESI/MSMS) to simultaneously quantify 28 urinary VOC metabolites as biomarkers of exposure. We describe a method that monitors metabolites of acrolein, acrylamide, acrylonitrile, benzene, 1-bromopropane, 1,3-butadiene, carbon-disulfide, crotonaldehyde, cyanide, N,N-dimethylformamide, ethylbenzene, ethylene oxide, propylene oxide, styrene, tetrachloroethylene, toluene, trichloroethylene, vinyl chloride and xylene. The method is accurate (mean accuracy for spiked matrix ranged from 84 to104%), sensitive (limit of detection ranged from 0.5 to 20ngmL(-1)) and precise (the relative standard deviations ranged from 2.5 to 11%). We applied this method to urine samples collected from 1203 non-smokers and 347 smokers and demonstrated that smokers have significantly elevated levels of tobacco-related biomarkers compared to non-smokers. We found significant (p<0.0001) correlations between serum cotinine and most of the tobacco-related biomarkers measured. These findings confirm that this method can effectively quantify urinary VOC metabolites in a population exposed to volatile organics. |
The influence of physicochemical properties on the internal dose of trihalomethanes in humans following a controlled showering exposure
Silva LK , Backer LC , Ashley DL , Gordon SM , Brinkman MC , Nuckols JR , Wilkes CR , Blount BC . J Expo Sci Environ Epidemiol 2012 23 (1) 39-45 Although disinfection of domestic water supply is crucial for protecting public health from waterborne diseases, this process forms potentially harmful by-products, such as trihalomethanes (THMs). We evaluated the influence of physicochemical properties of four THMs (chloroform, bromodichloromethane, dibromochloromethane, and bromoform) on the internal dose after showering. One hundred volunteers showered for 10 min in a controlled setting with fixed water flow, air flow, and temperature. We measured THMs in shower water, shower air, bathroom air, and blood samples collected at various time intervals. The geometric mean (GM) for total THM concentration in shower water was 96.2 mcg/l. The GM of total THM in air increased from 5.8 mcg/m(3) pre shower to 351 mcg/m(3) during showering. Similarly, the GM of total-blood THM concentration increased from 16.5 ng/l pre shower to 299 ng/l at 10 min post shower. THM levels were significantly correlated between different matrices (e.g. dibromochloromethane levels) in water and air (r=0.941); blood and water (r=0.845); and blood and air (r=0.831). The slopes of best-fit lines for THM levels in water vs air and blood vs air increased with increasing partition coefficient of water/air and blood/air. The slope of the correlation plot of THM levels in water vs air decreased in a linear (r=0.995) fashion with increasing Henry's law constant. The physicochemical properties (volatility, partition coefficients, and Henry's law constant) are useful parameters for predicting THM movement between matrices and understanding THM exposure during showering. (Journal of Exposure Science and Environmental Epidemiology advance online publication, 25 July 2012; doi:10.1038/jes.2012.80.) |
Quantitative analysis of six heterocyclic aromatic amines in mainstream cigarette smoke condensate using isotope dilution liquid chromatography-electrospray ionization tandem mass spectrometry
Zhang L , Ashley DL , Watson CH . Nicotine Tob Res 2010 13 (2) 120-6 INTRODUCTION: Heterocyclic aromatic amines (HAAs) represent an important class of carcinogens in mainstream cigarette smoke. Accurate HAA quantification is challenging because of their relative low abundances and numerous chemical interferences that arise naturally from thousands of the constituents present in cigarette smoke. We have developed and validated a straightforward high-throughput method to quantify HAA levels in mainstream cigarette smoke and demonstrated the applicability by analyzing select research and domestic cigarette brands. METHODS: Machine-smoked cigarette condensate collected under both standard and intensive smoking regimens was examined. Mainstream smoke particulate from individual cigarettes trapped on a glass fiber filter pad was spiked with an appropriate internal standard solution and subsequently solvent extracted. The extract was quantitatively analyzed by high-performance liquid chromatography and tandem mass spectrometry. RESULTS: Method validation data showed excellent accuracy, reproducibility and high throughput; it is suitable for the routine analysis of HAAs in cigarette smoke condensate delivered under a wide of differing smoking conditions. The smoking machine deliveries of HAAs are strongly influenced by cigarettes' physical design, filler blend, and smoking regimen. CONCLUSIONS: A quick and accurate method has been developed for the analysis of 6 HAAs in mainstream cigarette smoke condensate. Results provided a good mean to access the ranges of HAAs in commercial products and evaluate the relative contribution of cigarette design, filler blend, and smoking regimen on delivery. Such data are vital in helping provide exposure ranges for potential human exposure estimates. |
Tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in smokers in the United States: NHANES 2007-2008
Xia Y , Bernert JT , Jain RB , Ashley DL , Pirkle JL . Biomarkers 2010 16 (2) 112-9 The tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), a metabolite of the tobacco-specific nitrosamine (TSNA) 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), has been measured in urine samples from all participants aged 6 years and older from the National Health and Nutrition Examination Survey 2007-2008. Participants with a serum cotinine concentration of ≥10 ng/mL were identified as tobacco users, primarily cigarette smokers. Regression models were developed to calculate geometric mean NNAL concentrations adjusted for serum cotinine, urinary creatinine, cigarettes per day, and Federal Trade Commission tar values of the cigarettes smoked. Significant differences were found by gender (p = 0.003) and race/ethnicity (p = 0.022 for non-Hispanic white versus non-Hispanic black smokers), but not by menthol type of the cigarettes. Females and non-Hispanic white smokers had the highest adjusted means for urinary NNAL (353 and 336 pg/mL, respectively). The results from this study demonstrated significant relationships between NNAL concentrations and serum cotinine (p < 0.001) and urine creatinine (p < 0.001). The joint effect of linear and quadratic terms for number of cigarettes smoked per day was also statistically significant (p = 0.001). In addition to addressing current NNK exposure levels, these results will form a baseline for future estimates of tobacco users' exposure to this carcinogen. |
Global surveillance of oral tobacco products: total nicotine, unionised nicotine and tobacco-specific N-nitrosamines
Stanfill SB , Connolly GN , Zhang L , Jia LT , Henningfield JE , Richter P , Lawler TS , Ayo-Yusuf OA , Ashley DL , Watson CH . Tob Control 2010 20 (3) e2 OBJECTIVE: Oral tobacco products contain nicotine and carcinogenic tobacco-specific N-nitrosamines (TSNAs) that can be absorbed through the oral mucosa. The aim of this study was to determine typical pH ranges and concentrations of total nicotine, unionised nicotine (the most readily absorbed form) and five TSNAs in selected oral tobacco products distributed globally. METHODS: A total of 53 oral tobacco products from 5 World Health Organisation (WHO) regions were analysed for total nicotine and TSNAs, including 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), using gas chromatography or liquid chromatography with mass spectrometric detection. Unionised nicotine concentrations were calculated using product pH and total nicotine concentrations. Fourier transform infrared spectroscopy was used to help categorise or characterise some products. RESULTS: Total nicotine content varied from 0.16 to 34.1 mg/g product, whereas, the calculated unionised nicotine ranged from 0.05 to 31.0 mg/g product; a 620-fold range of variation. Products ranged from pH 5.2 to 10.1, which translates to 0.2% to 99.1% of nicotine being in the unionised form. Some products have very high pH and correspondingly high unionised nicotine (eg, gul powder, chimo, toombak) and/or high TSNA (eg, toombak, zarda, khaini) concentrations. The concentrations of TSNAs spanned five orders of magnitude with concentrations of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) ranging from 4.5 to 516 000 ng/g product. CONCLUSIONS: These data have important implications for risk assessment because they show that very different exposure risks may be posed through the use of these chemically diverse oral tobacco products. Because of the wide chemical variation, oral tobacco products should not be categorised together when considering the public health implications of their use. |
Urine concentrations of a tobacco-specific nitrosamine carcinogen in the U.S. population from secondhand smoke exposure
Bernert JT , Pirkle JL , Xia Y , Jain RB , Ashley DL , Sampson EJ . Cancer Epidemiol Biomarkers Prev 2010 19 (11) 2969-77 BACKGROUND: The tobacco-specific nitrosamine NNK (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone) and its reduction product in the body, NNAL (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol), are potent pulmonary carcinogens. We have measured total NNAL in the U.S. population of tobacco users and nonsmokers exposed to secondhand smoke (SHS). METHODS: We measured total urinary NNAL (free NNAL plus its glucuronides following hydrolysis) by using a sensitive and specific high-performance liquid chromatography / tandem mass spectrometry method. We calculated the percentage above the LOD, the 50th through 95th percentiles, and in some cases geometric means for groups classified by age, gender and race/ethnicity. RESULTS: Total urinary NNAL was measureable at or above its limit of detection (0.6 pg/mL) in 55% of the study participants, including 44% of nonsmokers. The population distribution of urinary NNAL included smoker and nonsmoker regions similar to the bimodal distribution of serum cotinine, and serum cotinine and total urinary NNAL were strongly correlated (r = 0.92; p<0.001). Among nonsmokers, children had significantly higher concentrations of NNAL than did adults aged ≥20 years (p < 0.001). CONCLUSIONS: Among NHANES participants, total NNAL was found at measurable levels in the urine of 44% of nonsmokers, and in 87.5% of those with substantial SHS exposure (with serum cotinine concentrations of 0.1 to 10 ng/mL). Children aged 6-11 years had the highest NNAL concentrations among all nonsmokers. IMPACT: We describe for the first time the distribution of total urinary NNAL in the entire U.S. population including both smokers and nonsmokers. NNAL was detected in 44% of all nonsmokers. |
Effect of differing levels of tobacco-specific nitrosamines in cigarette smoke on the levels of biomarkers in smokers
Ashley DL , O'Connor RJ , Bernert JT , Watson CH , Polzin GM , Jain RB , Hammond D , Hatsukami DK , Giovino GA , Cummings KM , McNeill A , Shahab L , King B , Fong GT , Zhang L , Xia Y , Yan X , McCraw JM . Cancer Epidemiol Biomarkers Prev 2010 19 (6) 1389-98 BACKGROUND: Smokers are exposed to significant doses of carcinogens, including tobacco-specific nitrosamines (TSNA). Previous studies have shown significant global differences in the levels of TSNAs in cigarette smoke because of the variation in tobacco blending and curing practices around the world. METHODS: Mouth-level exposure to 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) measured in cigarette butts and urinary concentrations of its major metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) were examined among 126 daily smokers in four countries over a 24-hour study period. RESULTS: As mouth-level exposure of NNK increased, the urinary NNAL increased even after adjustment for other covariates (beta = 0.46, P = 0.004). The relationship between mouth-level exposure to nicotine and its salivary metabolite, cotinine, was not statistically significant (beta = 0.29, P = 0.057), likely because of the very limited range of differences in mouth-level nicotine exposure in this population. CONCLUSIONS: We have shown a direct association between the 24-hour mouth-level exposure of NNK resulting from cigarette smoking and the concentration of its primary metabolite, NNAL, in the urine of smokers. Internal dose concentrations of urinary NNAL are significantly lower in smokers in countries that have lower TSNA levels in cigarettes such as Canada and Australia in contrast to countries that have high levels of these carcinogens in cigarettes, such as the United States. Impact: Lowering the levels of NNK in the mainstream smoke of cigarettes through the use of specific tobacco types and known curing practices can significantly affect the exposure of smokers to this known carcinogen. (c)2010 AACR. |
Semi-volatiles in mainstream smoke delivery from select charcoal-filtered cigarette brand variants
Hearn BA , Ding YS , Vaughan C , Zhang L , Polzin G , Caudill SP , Watson CH , Ashley DL . Tob Control 2010 19 (3) 223-30 BACKGROUND: It has been reported that charcoal added to cigarette filters selectively removes many of the more volatile chemicals, but it is not clear to what extent charcoal may reduce the delivery of important less volatile chemical constituents in mainstream cigarette smoke. METHODS: We analysed machine-derived mainstream smoke deliveries (under three smoking regimens) for variants of a charcoal-filtered cigarette commercially test-marketed in the USA, focusing on selected polycyclic aromatic hydrocarbons (PAHs), phenols and tobacco-specific nitrosamines (TSNAs). Results While charcoal-containing filters selectively removed lower molecular weight PAHs from mainstream smoke, they did not significantly remove the heavier and more toxic PAHs studied, such as benzo[a]pyrene, a known carcinogen. Likewise, charcoal-containing filters removed phenols and TSNAs from mainstream smoke to differing amounts depending on the compound, filter design and the smoking regimen. CONCLUSIONS: The addition of sufficient charcoal to cigarette filters is known to remove many volatile compounds and can potentially reduce deliveries of certain semi-volatile compounds under some machine smoking regimens. Less volatile compounds, with a significant portion in the particulate phase, are less available for selective filtration by charcoal-containing filters than the more volatile compounds that reside predominantly in the gas phase. |
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