Research Section
A comparison of the mainstream smoke chemistry and mutagenicity of a representative sample of the US cigarette market with two Kentucky reference cigarettes (K1R4F and K1R5F)

https://doi.org/10.1016/S0278-6915(00)00086-7Get rights and content

Abstract

The incorporation of technologies into cigarettes such as filters, filter ventilation, porous cigarette papers, expanded tobacco and reconstituted tobacco sheet has resulted in cigarettes with a wide range of “tar” yields. The objectives of this study were to characterize the US cigarette market according to “tar” category (i.e. full flavor, FF; full flavor low tar, FFLT; or ultra low tar, ULT) and to determine whether the Kentucky reference cigarettes K1R4F and K1R5F are representative of FFLT and ULT cigarettes, respectively. As a means of characterization and comparison, the mainstream smoke from a representative sample of commercially available cigarettes from each market segment and the K1R4F and K1R5F Kentucky reference cigarettes was analyzed for the presence and level of 18 selected chemical constituents. In addition, a measure of the mutagenic activity of the mainstream smoke condensate from these cigarettes was determined using an Ames Salmonella mutagenicity assay. All cigarettes were smoked according to US Federal Trade Commission (FTC) guidelines. Results indicated that, overall, mainstream smoke constituent levels are well predicted by FTC “tar” yield—constituent levels increased as “tar” delivery increased. Based on the selected analytes measured in mainstream smoke, the K1R4F reference cigarette was generally representative of the FFLT segment of the US cigarette market. The K1R5F reference cigarette was representative of the ULT segment of the US cigarette market for cigarettes with “tar” deliveries approximate to it. In terms of mutagenic activity, a direct relationship was also demonstrated on a per cigarette basis—revertants per cigarette increased with increasing “tar” delivery. There was a weak tendency (R-square=0.12, P=0.08) for specific activity (revertants/mg “tar”) to increase with decreasing “tar” yield—lower “tar” products had a slightly higher specific activity. No significant differences (P>0.05) were observed when the specific activities of the condensates from the K1R4F and K1R5F reference cigarettes were compared to the market segments that they were designed to represent, FFLT and ULT, respectively. Overall, these results support the use of the K1R4F and the K1R5F as acceptable reference cigarettes for comparative mutagenicity and smoke chemistry studies of cigarettes available on the US market.

Introduction

Cigarette design has evolved over the last several decades with the incorporation of many new technologies. Modifications to cigarette design have involved the incorporation of new tobacco processes, papers, filters and flavoring ingredients which either alone or in combination have the potential to modify the quantity and/or the quality of the smoke yielded from the cigarette. The incorporation of these new technologies and materials has resulted in the development a diverse market of commercial cigarettes encompassing a wide range of “tar” yields. Collectively, these technologies interact within the complex system of the burning cigarette and, ultimately, influence the mainstream smoke formed during the smoking process.

During the last 30 to 40 years, a great deal of information has been published regarding the identity of chemicals commonly observed in mainstream cigarette smoke (see Hoffmann, 1993, IARC, 1985, US Surgeon General, 1989). Over this time, significant changes in cigarette design (e.g. air dilution) and tobacco processes, and reductions in “tar” have been incorporated by manufacturers. In addition, the activity of mainstream cigarette smoke condensate in in vitro genotoxicity assays has been addressed in the scientific literature (DeMarini, 1981, DeMarini, 1983). However, few studies have attempted to concurrently characterize the smoke chemistry and/or the biological activity of the commercial cigarettes presently available on the US market. Recently, members of both the public health and regulatory communities have expressed interest in such data.

As cigarette design has continued to evolve, comparative chemical and biological studies of mainstream smoke have formed the foundation of product evaluation strategies adopted to characterize the potential impact of product modification. Owing to the complexity of the cigarette system (attributable to physical cigarette design parameters, variations in tobacco blends and ingredients), the selection of appropriate reference cigarettes for use in comparative product stewardship studies can be challenging.

Fortunately, a series of cigarettes has been developed jointly by the US National Cancer Institute, the Agriculture Research Service of the US Department of Agriculture, and the University of Kentucky Tobacco and Health Research Institute (Lexington, Kentucky) to serve as reference cigarettes for experimental purposes (Davis, Vaught, Tso and Bush, 1984, Sullivan, 1984). These cigarettes, generally referred to as “Kentucky reference cigarettes,” incorporate the principal cigarette design advances that have been introduced onto the market since the 1950s. The intention in developing these cigarettes was to provide standard reference cigarettes for use in comparative chemical and biological studies of cigarette smoke. As reference cigarettes, they also provide a basis for comparing data collected in different laboratories and at different points in time.

The K1R4F and K1R5F are two Kentucky reference cigarettes that incorporate the design features typical of low “tar” cigarettes. As such, standard smoke component yields—for example “tar” (total particulate matter minus nicotine and water), nicotine and carbon monoxide—for the K1R4F and K1R5F are typical of low and ultra low tar cigarette designs, respectively. The K1R4F cigarette incorporates filtration, air dilution, and a tobacco blend that includes reconstituted tobacco sheet to achieve smoke yields typical of a low tar cigarette. The K1R5F cigarette incorporates expanded or “puffed” tobacco into the blend, in addition to the design technologies included in the K1R4F cigarette, to produce smoke yields typical of an ultra low tar cigarette.

The K1R4F, developed in 1983, is an 84 mm length, 25 mm circumference cigarette with a cellulose acetate filter that yields, on average, 9.2 mg “tar” and 0.8 mg nicotine when smoked under standard Federal Trade Commission (FTC) conditions (35 ml puff volume, 2 sec duration, 1 puff/min, smoked to a butt length within 3 mm of the edge of the tipping paper for filtered cigarettes and a butt length of 23 mm for unfiltered cigarettes). Based on the tobacco blend, “tar”, nicotine and carbon monoxide yields (in relation to the US sales weighted average), the K1R4F was designed to be representative (on average) of the US cigarette market, in general, and the full flavor low tar (FFLT) segment, in particular. The K1R5F, developed in 1989, is an 84 mm length, 25 mm circumference cigarette with a cellulose acetate filter that yields, on average, 1.7 mg “tar” and 0.2 mg nicotine when smoked under standard FTC conditions. Based on the tobacco blend, “tar”, nicotine and carbon monoxide yields, the K1R5F was designed as a reference cigarette for the ultra low tar (ULT) segment of the US cigarette market.

In 1995, Steele et al.. compared the mutagenicity of mainstream cigarette smoke condensates from a representative sample of the US cigarette market with a Kentucky reference cigarette (the K1R4F). These investigators demonstrated that the K1R4F, as assessed by the Salmonella assay, was a representative model for the US cigarette market using mainstream smoke condensates. To date, the mutagenicity of the K1R5F has not been evaluated in relation to ultra low tar cigarettes currently available on the US market. Further, to date, no reported study has been published which compares the levels of mainstream smoke analytes of commercial cigarettes available on the US market with either the K1R4F or the K1R5F.

Findings from this study expand on and complement the earlier work of Steele et al. (1995) in the area of mutagenicity, and also address the current interest of the health and regulatory community concerning more extensive information about mainstream smoke chemistry yields from cigarettes marketed today. The specific objectives of this study were twofold: (1) to characterize the US cigarette market in terms of mainstream smoke chemistry and mainstream smoke condensate mutagenicity; and (2) to determine whether the Kentucky reference cigarettes K1R4F and K1R5F are representative of commercial FFLT and ULT cigarettes, respectively.

Section snippets

Cigarette sample

For sample selection, the 1995 US cigarette market was initially stratified into 12 different market sections: first, according to “tar” category (full flavor, FF; full flavor low tar, FFLT; or ultra low tar, ULT), then according to menthol inclusion (menthol or non-menthol), and finally according to price (full price or savings). In stratifying according to “tar” category, package self-designation was the primary criterion (typically, the standard “tar” delivery range for each of the

Mainstream smoke constituent analyses

Table 1, Table 2, Table 3 contain the results of the mainstream smoke constituent analyses according to “tar” category for the 18 analytes examined. Table 1 contains the results for the market cigarettes in the full flavor low tar (FFLT) category and also includes the results from the Kentucky reference cigarette, K1R4F. Table 2 contains the results for the market cigarettes in the ultra low tar (ULT) category and also includes the results from the Kentucky reference cigarette, K1R5F. Table 3

Discussion

Many design differences can and do exist among different styles of commercially marketed cigarettes. These include the quantity and types of tobacco utilized (including reconstituted tobacco sheet and expanded tobacco); the crop year(s) of the tobacco utilized; the quantity and types of ingredients utilized; the non-tobacco materials utilized (i.e. papers and filters); and the physical design of the cigarette. These differences in cigarette design have resulted in the development of a diverse

References (28)

  • Cochran W. G. (1977) Sampling Techniques. Wiley series in probability and mathematical statistics. John Wiley & Sons,...
  • P.F Collins et al.

    An automated method for determination of hydrogen cyanide in cigarette smoke

    Tobacco Science

    (1970)
  • D.L Davis et al.

    Analysis of a new low yield research cigarette

    (1984)
  • D.J Doolittle et al.

    Comparative studies on the genetoxic activity of mainstream smoke condensate from cigarettes which burn or only heat tobacco

    Environmental and Molecular Mutagenesis

    (1990)
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