Clifford H. Watson

Global surveillance of oral tobacco products: total nicotine, unionised nicotine and tobacco-specific N-nitrosamines

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, chimó, 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.

Surveillance of moist snuff: total nicotine, moisture, pH, un-ionized nicotine, and tobacco-specific nitrosamines

In 2005, approximately 2.3% of U.S. adults used smokeless tobacco. Moist snuff leads all types of smokeless tobacco in revenues and marketing expenditures. The U.S. Surgeon General has concluded that smokeless tobacco use can lead to nicotine addiction. The National Toxicology Program of the National Institutes of Health has classified smokeless tobacco as a human carcinogen. Tobacco-specific nitrosamines (TSNAs) are potent carcinogens in smokeless tobacco products, and the pH of the product influences the content of un-ionized nicotine which is the form of nicotine most rapidly absorbed in the mouth. The Centers for Disease Control and Prevention analyzed 40 top-selling brands of moist snuff to measure nicotine, moisture, pH, un-ionized nicotine, and TSNAs, including 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL). The study findings indicate that moist snuff brands varied widely in content of rapidly absorbed, addictive un-ionized nicotine (500-fold range) and of carcinogenic TSNAs (18-fold range). Product characteristics such as packaging and moisture content appeared to be correlated with concentrations of un-ionized nicotine, and flavor characteristics of low-priced brands may correlate with TSNA concentrations. These findings warrant further study in light of (a) the marketing of smokeless tobacco for use in places where smoking is prohibited, (b) the promotion of smokeless tobacco as a harm-reduction product, and (c) the ever-expanding number of highly flavored smokeless varieties brought to the market.

Determination of tar, nicotine, and carbon monoxide yields in the mainstream smoke of selected international cigarettes

Objective: Survey of nicotine, tar, and carbon monoxide (CO) smoke deliveries from 77 cigarette brands purchased in 35 countries was conducted using a standardised machine smoking method. The goal of this study was to determine regional variations and differences in the tar, nicotine, and CO smoke yields of a cigarette brand manufactured by a leading transnational corporation and of non-US locally popular cigarette brands. Design: The majority of the cigarettes were purchased in each of the participating countries by delegate members of the World Health Organization and forwarded to the Centers for Disease Control and Prevention for analysis. Smoke deliveries were determined using a standardised smoking machine method and subsequent gravimetric and gas chromatography analysis. Results: The smoke deliveries varied widely. Mainstream smoke deliveries varied from 6.8 to 21.6 mg tar/cigarette, 0.5 to 1.6 mg nicotine/cigarette, and 5.9 to 17.4 mg CO/cigarette. In addition to the smoke deliveries, the cigarettes were examined to determine physical parameters such as filter composition, length, and ventilation levels. Conclusion: Analysis of the smoke deliveries suggested that cigarettes from the Eastern Mediterranean, Southeast Asia, and Western Pacific WHO regions tended to have higher tar, nicotine, and CO smoke deliveries than did brands from the European, American, or African WHO regions surveyed.

Chemical Composition and Evaluation of Nicotine, Tobacco Alkaloids, pH, and Selected Flavors in E-Cigarette Cartridges and Refill Solutions

INTRODUCTION Electronic cigarette (e-cigarette) use is increasing dramatically in developed countries, but little is known about these rapidly evolving products. This study analyzed and evaluated the chemical composition including nicotine, tobacco alkaloids, pH, and flavors in 36 e-liquids brands from 4 manufacturers. METHODS We determined the concentrations of nicotine, alkaloids, and select flavors and measured pH in solutions used in e-cigarettes. E-cigarette products were chosen based upon favorable consumer approval ratings from online review websites. Quantitative analyses were performed using strict quality assurance/quality control validated methods previously established by our lab for the measurement of nicotine, alkaloids, pH, and flavors. RESULTS Three-quarters of the products contained lower measured nicotine levels than the stated label values (6%-42% by concentration). The pH for e-liquids ranged from 5.1-9.1. Minor tobacco alkaloids were found in all samples containing nicotine, and their relative concentrations varied widely among manufacturers. A number of common flavor compounds were analyzed in all e-liquids. CONCLUSIONS Free nicotine levels calculated from the measurement of pH correlated with total nicotine content. The direct correlation between the total nicotine concentration and pH suggests that the alkalinity of nicotine drives the pH of e-cigarette solutions. A higher percentage of nicotine exists in the more absorbable free form as total nicotine concentration increases. A number of products contained tobacco alkaloids at concentrations that exceed U.S. pharmacopeia limits for impurities in nicotine used in pharmaceutical and food products.

Concentrations of nine alkenylbenzenes, coumarin, piperonal and pulegone in Indian bidi cigarette tobacco.

Indian-made bidi cigarettes sold in the United States are available in a variety of exotic (e.g. clove, mango) and candy-like (e.g. chocolate, raspberry) flavors. Because certain tobacco flavorings contain alkenylbenzenes and other toxic or carcinogenic chemicals, we measured the concentration of flavor-related compounds in bidi tobacco using a previously developed method. Twenty-three brands of bidis were sampled using automated headspace solid-phase microextraction and subsequently analyzed for 12 compounds by gas chromatography-mass spectrometry. Two alkenylbenzene compounds, trans-anethole and eugenol, were found in greater than 90% of the brands analyzed. Methyleugenol, pulegone and estragole were each detected in 30% or more of the brands, whereas safrole and elemicin were not detected in any of the brands. The flavor-related compounds with the highest tobacco concentrations were eugenol (12,000 microg/g tobacco) and trans-anethole (2200 microg/g tobacco). The highest eugenol and trans-anethole concentrations found in bidi tobacco were about 70,000 and 7500 times greater, respectively, than the highest levels previously found in US cigarette brands. Measurement of these compounds is crucial to evaluation of potential risks associated with inhaling highly concentrated flavor-related compounds from bidis or other tobacco products.

Establishment of Toxic Metal Reference Range in Tobacco from US Cigarettes

Smoking remains the leading cause of preventable death in the United States. There are numerous harmful substances in tobacco and tobacco smoke. Among the more than 4,000 identified compounds in smoke, many metals contribute to the health risks associated with tobacco use. Specific metals found in tobacco and tobacco smoke have been classified as carcinogens by the International Agency for Research on Cancer. Exposure to toxic metals can cause outcomes including inflammation, sensitization and carcinogenesis. Metals in tobacco are transported in tobacco smoke proportionally with their concentrations in tobacco filler for a given cigarette design. To quantitatively examine the metal content in numerous tobacco products, high throughput methods are desired. This study developed a simple, rapid tobacco digestion method coupled with a sensitive analytical method using inductively coupled plasma-mass spectrometry. Because of known memory effects and volatility of mercury, quantitative determinations of mercury were made with a direct combustion analyzer. The methods were utilized to examine arsenic, beryllium, cadmium, chromium, cobalt, lead, manganese, mercury and nickel contents in cigarette tobacco and to establish a reference range for the metals in 50 varieties of cigarettes available in the US. These results are comparable to the limited data sets reported by others and with available standard reference material values.

Determination of Carcinogenic Tobacco-Specific Nitrosamines in Mainstream Smoke from U.S.-brand and non-U.S.-brand Cigarettes from 14 Countries

Tobacco-specific nitrosamines (TSNAs) comprise one of the major classes of carcinogenic compounds in mainstream cigarette smoke. As part of collaborative efforts between the World Health Organization and the U.S. Centers for Disease Control and Prevention (CDC) to reduce tobacco use and resulting disease, the CDC examined carcinogenic TSNA levels from cigarettes obtained from selected countries around the world. Using a modern, high-throughput liquid chromatography/mass spectrometry/mass spectrometry method under stringent quality control protocols, we determined the carcinogenic TSNA levels in mainstream smoke from a globally marketed brand, Marlboro, and from local top-selling cigarette brands from 14 countries. The levels of carcinogenic TSNAs in mainstream smoke collected using a 35-ml puff volume, 60-s puff interval, and 2-s puff duration correlated well (R=0.79, p<.0001) with previously reported levels in the corresponding tobacco filler. Marlboro cigarettes purchased in 10 countries had significantly higher carcinogenic TSNA levels in mainstream smoke than did local-brand cigarettes from the same country. In only one country, Brazil, were the carcinogenic TSNA levels in mainstream smoke from Marlboro cigarettes significantly lower than in the locally popular brand. However, carcinogenic TSNA levels in mainstream smoke from Brazilian Marlboro cigarettes were usually lower than those in mainstream smoke from the Marlboros purchased in the other 13 countries, suggesting a reason for the difference. The wide range of mainstream smoke carcinogenic TSNA levels measured in the present study (8.7-312 ng/cigarette) suggest that manufacturers can lower the carcinogenic TSNA levels and that, for similar filter ventilation, carcinogenic TSNA levels in the tobacco filler of a cigarette are a useful indicator of the corresponding levels in mainstream smoke.

Toxic Metal Concentrations in Mainstream Smoke from Cigarettes Available in the USA

Public health officials and leaders of 168 nations have signaled their concern regarding the health and economic impacts of smoking by becoming signatory parties to the World Health Organization Framework Convention on Tobacco Control (FCTC). One of FCTCs purposes is to help achieve meaningful regulation for tobacco products in order to decrease the exposure to harmful and potentially harmful constituents (HPHCs) delivered to users and those who are exposed to secondhand smoke. Determining baseline delivery ranges for HPHCs in modern commercial tobacco products is crucial information regulators could use to make informed decisions. Establishing mainstream smoke delivery concentration ranges for toxic metals was conducted through analyses of total particulate matter (TPM) collected with smoking machines using standard smoking regimens. We developed a rapid analytical method with microwave digestion of TPM samples obtained with smoking machines using electrostatic precipitation under the ISO and Intense smoking regimens. Digested samples are analyzed for chromium, manganese, cobalt, nickel, arsenic, cadmium and lead using inductively coupled plasma-mass spectrometry. This method provides data obtained using the ISO smoking regimen for comparability with previous studies as well as an Intense smoking regimen that represents deliveries that fall within the range of human exposure levels to toxic metals.

Effect of Differing Levels of Tobacco-Specific Nitrosamines in Cigarette Smoke on the Levels of Biomarkers in Smokers

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 (β = 0.46, P = 0.004). The relationship between mouth-level exposure to nicotine and its salivary metabolite, cotinine, was not statistically significant (β = 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. Cancer Epidemiol Biomarkers Prev; 19(6); 1389–98. ©2010 AACR.

Tobacco-specific nitrosamines in tobacco from U.S. brand and non-U.S. brand cigarettes

Tobacco-specific nitrosamines (TSNAs) are one of the major classes of carcinogens found in tobacco products. As part of collaborative efforts to reduce tobacco use and resulting disease, the U.S. Centers for Disease Control and Prevention (CDC) carried out a two-phase investigation into the worldwide variation of the levels of TSNAs in cigarette tobacco. In the first phase, representatives of the World Health Organization (WHO) purchased cigarettes; scientists from the CDC subsequently measured the levels of TSNAs in tobacco from 21 different countries. Although the data collected from this initial survey suggested that globally marketed U.S.-brand cigarettes typically had higher TSNA levels than locally popular non-U.S. cigarettes in many countries, the number of samples limited the statistical power of the study. To improve statistical power and to ensure adequate sampling, the CDC conducted a second survey of 14 countries. In addition to the United States, the CDC selected the worlds 10 most populous countries and three additional countries, so that at least two countries from each of the six WHO regions were represented. For each country, the CDC compared 15 packs of Marlboro cigarettes, which is the worlds most popular brand of cigarettes, with 15 packs of a locally popular non-U.S. brand in the study country. Marlboro cigarettes purchased in 11/13 foreign countries had significantly higher tobacco TSNA levels than the locally popular non-U.S. brands purchased in the same country. The findings suggest that TSNA levels in tobacco can be substantially reduced in some cigarettes.