Article Cite This: Chem. Res. Toxicol. 2018, 31, 251−258
pubs.acs.org/crt
Cigarillo and Little Cigar Mainstream Smoke Constituents from Replicated Human Smoking Wallace B. Pickworth,*,† Zachary R. Rosenberry,† Daniel Yi,‡ Emily N. Pitts,§ Wilhelmina Lord-Adem,‡ and Bartosz Koszowski† †
Battelle Memorial Institute, Public Health Center for Tobacco Research, 6115 Falls Road Suite 200, Baltimore, Maryland 21209, United States ‡ University of Maryland School of Pharmacy, 20 North Pine Street, Baltimore, Maryland 21201, United States § Notre Dame of Maryland University School of Pharmacy, 4701 North Charles Street, Baltimore, Maryland 21210, United States S Supporting Information *
ABSTRACT: Little cigar and cigarillo smoking is increasing in popularity in the U.S., but little is known about the topography and mainstream smoke (MSS) constituents of these types of cigar products. This report describes the quantity of selected MSS toxicants generated from puff-by-puff replication of human laboratory smoking. Participants were dual users of cigarettes and either little cigars (n = 21) or cigarillos (n = 23). In the laboratory smoking session, participants of the little cigar group smoked a filtered unflavored Winchester Little Cigar; those in the cigarillo group smoked an unfiltered, unflavored Black & Mild cigarillo. MSS components included both volatiles and semivolatile compounds. The MSS of five representative U.S. domestic cigarettes was generated using smoking topography profiles of the participants smoking their own brand of cigarettes. Machine smoking accurately replicated individual puff profiles as indicated by a high correlation between lab and machine smoked: time to smoke, number of puffs, and total puff volume. There was wide variability in smoking patterns across subjects of both little cigars and cigarillos. For example, total puff volume ranged from 84 to 732 mL after the little cigar and from 270 to 2089 mL after the cigarillo. Qualitatively, cigar smoke from little cigars and cigarillos were similar and resembles cigarette smoke. All analytes (VOC and SVOCs) were greater in cigarillo smoke compared to that of little cigars and cigarettes. However, when the toxicants were adjusted for grams of tobacco burned, little cigar smoke contained more nicotine, tobaccospecific nitrosamines, acetonitrile, and acrylonitrile compared with cigarillo smoke. When the constituents were adjusted for nicotine content, cigarillo MSS contained more of all toxicants compared with little cigar. Cigarillos and little cigars, like cigarettes, deliver nicotine and other toxicants known to be harmful to health; their regulation by the FDA is appropriate for their public health risk.
■
and Mass Manufactured Cigars (MMCs), filtered little cigars, and premium cigars.6 By contrast, the U.S. Government defines cigars that weigh less than 1.36 g each (i.e., > 3 lbs./1000 articles) as little cigars regardless of other design characteristics such as filters, tipping or packaging size, and number per pack. States may impose different standards. For example, Pennsylvania sets a limit of 4 lbs/1000 or 1.8 g each as a little cigar.7 Even among cigar consumers, there is no uniformity or agreement in designating the cigar products they use.8 The establishment of a standardized classification of cigars products have important regulatory and health implications. For example, daily cigar smoking was reported in only 3.6% of premium cigar smokers, 13% of cigarillo/MMC smokers and 36% of filtered little cigars smokers.6 The distribution of cigar smoking by age, ethnicity, and gender is dependent on the designation of the cigar products. Generally
INTRODUCTION
In the United States (U.S.), the prevalence of cigarette smoking and per capita cigarette consumption have steadily decreased since 1964;1−3 however, U.S. cigar use has doubled in recent years.1 Current surveys indicate that more than 1 in 20 U.S. adults smoke a cigar product “every day”, “some days”, or “rarely.”4 Other studies estimate that about 17 million Americans smoke cigar products, and regular cigar use is estimated to be responsible for about 9000 premature deaths per year. Cigars were recently deemed by the Food and Drug Administration (FDA) to be subject to their authority; however, acceptable and standardized classification of cigars is still not available. As a result, various types of cigar products (e.g., large cigars, cigarillos, and little cigars) are lumped together without an appreciation or an understanding of whether these are similar articles. Some researchers have distinguished cigar products by size: little cigars, cigarillos, and large cigars.2 Others have combined little cigars and cigarillos into a single group5 or have categorized products as cigarillos © 2018 American Chemical Society
Received: November 17, 2017 Published: March 27, 2018 251
DOI: 10.1021/acs.chemrestox.7b00312 Chem. Res. Toxicol. 2018, 31, 251−258
Article
Chemical Research in Toxicology
study; although, it is adaptable for other studies that use the SPA/D topography and Cerulean smoking machine. The interface also adopted routines for operator-review of the data, including an import function to bring the SPA/D data to the interface, editing capability to remove artifacts and a “noise threshold” on the data so that small nonzero values of puff velocity between puffs were eliminated from the data used to drive the smoking machine, rescaling capability, and an export routine. Furthermore, the interface also provides the capability to set the machine smoke according to preset regimens (e.g., ISO) or to operator-selected smoking parameters where the puffs are identical over the entire article (cigar or cigarette) smoked. The operator defined parameters feature was used in the present study to generate smoke from five representative types of U.S. domestic cigarettes to provide a comparison with constituents of MSS from a filtered cigar, cigarillo, and cigarette. Further details of the interface are available in Supporting Information or from the author (WBP). Mainstream Smoke (MSS) Analysis. Enthalpy Analytical (Richmond, VA), a fully accredited,17 independent tobacco testing company, analyzed MSS from each of the filtered little cigar (n = 21), the cigarillo (n = 23), and five selected U.S. cigarettes. Validated analytical methods (summarized in Supporting Information) were used to determine quantitatively levels of selected volatile (VOC) and semivolatile organic (SVOC) components of MSS. The selected analytes and their limit of detection (LOD) and limit of quantitation (LOQ) are shown in Table 1. We choose to test these compounds
younger, poorer, minority men tend to smoke more little cigars and cigarillos, whereas wealthier, better educated men tend to smoke premium cigars.9 In previous publications, we reported on differences among smoking topography, nicotine, and carbon monoxide exposure from little cigars10,11 and cigarillos.12 In the present report, we describe the puff-by-puff replication of human laboratory smoking with a smoking machine and the subsequent analyses of selected volatile and semivolatile toxicants in the mainstream smoke (MSS). The approach extends the results from paradigms that estimate toxicant yield from cigarette smoking based on standardized smoking patterns such as the International Organization for Standardization (ISO) and Federal Trade Commission (FTC).13,14 Although machine smoking of cigarettes has been recognized as not reflective of human smoking,15 it nevertheless provides a basis for objectively comparing smoke emissions in MSS across a wide range of cigarette products. The wide variations in smoking topography among cigar products16 complicates the development of a representative machine standard for all cigars. The differences between the various types of cigar products and the use patterns of their consumers have made generalizations about cigar use and their impact on health difficult to establish. Those challenges are addressed in the present report that characterizes toxicants generated from machine-replicated human smoking. One purpose of the present report was to report on the range of smoking topography variables from laboratory smoking of a popular filtered little cigar and a popular unfiltered cigarillo to determine how closely these topography variables agree with the published standards. A second purpose of the present study was to distinguish qualitative and quantitative differences between selected MSS toxicants of a filtered little cigar, an unfiltered cigarillo, and cigarettes to emphasize differences toxicant delivery between products.
■
Table 1. LoD and LoQ for Volatile and Semivolatile Compounds semivolatile compounds nicotine NNKb NNNc B[a]Pd volatile compounds 1,3-butadiene 2,5-dimethylfuran acetaldehyde acetonitrile acrylonitrile benzene quinoline
MATERIALS AND METHODS
Clinical Study. Two groups of volunteer participants who were dual users of cigarettes (≥10/day) and either a little cigar (n = 21) or a cigarillo (n = 23) visited the laboratory on two separate days. At one visit, participants smoked their usual brand of cigarette. At the other visit, participants of one group smoked an unflavored Winchester (Scandinavian Tobacco Group, Tucker, GA) filtered little cigar (n = 21) and those of the other group smoked an unflavored, unfiltered Black & Mild (John Middleton; King of Prussia, PA) cigarillo (n = 23). Presentation of the smoking conditions was randomized. Participants were instructed to smoke the articles ad lib and to smoke only as much of the article as they ordinarily would. They smoked through a mouthpiece of a Smoking Puff Analyzer topography device (SPA/D; Sodim Instrumentation, Mebane, NC)the device recorded the time to smoke, the number of puffs, and the individual puff profiles of each puff. The amount of tobacco burned in the session was determined by weighing the cigars before and after each smoking session. Further experimental details and the characteristics of the participant sample are provided in previous publications.10,12 Puff Replication. Enthalpy Analytical (Richmond, VA) developed a proprietary software interface between SPA/D smoking topography data from the participants’ laboratory smoking sessions and a linear smoking machine (Cerulean, Milton Kaynes, U.K.) so that the puffs from each participant could be replicated by the smoking machine on puff-by-puff basis. In general, the interface was a software program that converted the raw SPA data (flow rates) to. EPOP file that drove the vacuum stepper motors of the cigarette smoking machine. The interface algorithm is under the control of the user, providing the opportunity for smoothing, concatenating, and profile creation. The software developed for the interface was written specifically for this
method
LoD
LoQ
GC/FID; AM-001 LC/MS; AM-020 LC/MS; AM-020 GC/MS AM-044 method
6.0 μg/cig 0.6 ng/cig 1.0 ng/cig 0.8 ng/cig LoD
20 μg/cig 16 ng/cig 16 ng/cig 2.0 ng/cig LoQ
GC/MS; AM-015 GC/MS; AM-015 UHPLC; AM-076 GC/MS; AM-015 GC/MS; AM-015 GC/MS; AM-015 GC/MS; AM-006
3.2 1.8 0.6 1.8 1.8 2.8 0.0
μg/cig μg/cig μg/cig μg/cig μg/cig μg/cig μg/cig
10.8 μg/cig 6.4 μg/cig 42 μg/cig 6.4 μg/cig 6.4 μg/cig 10 μg/cig 2.0 μg/cig
a
AM methods correspond to Arista protocols for analyses of MSS components. Details are listed in Supporting Information; GC/FID − gas chromatography with flame ionization detection; GC/MS − gas chromatography/mass spectrometry; LC/MS − liquid chromatography with mass spectrometry; UHPLC − ultra high pressure liquid chromatography. bNicotine-derived nitrosamine ketone. cN-nitrosonornicotine. dIncluded among semivolatile compounds (here and in other tables) because B[a]P is captured in the filter with other semivolatiles but it is recognized as a particle organic compound.45 because nicotine has been identified as addictive;18 other selected components are irritants and/or carcinogenic, and many are identified by the FDA as harmful or potentially harmful constituents of tobacco smoke.19 The general approach to the MS analysis was collection of the particle phase of the smoke aerosol on a Cambridge filter pad and by capturing the volatile compounds with an impinger solution containing 20 mL of methanol or methanol/triethylamine immersed in a dry ice/isopropyl alcohol bath. Semivolatile compounds were analyzed from the residue on the Cambridge filter pad, whereas the volatile components were recovered and analyzed from the impinger solution. Further details of the procedure are available in Supporting Information, from the author (WBP) or from Enthalpy Analytical (Richmond, VA); reference report no. 14203 Arista Protocol. Cigarette Smoking. In one of the experimental laboratory visits, the participants smoked their usual brand of cigarette through the 252
DOI: 10.1021/acs.chemrestox.7b00312 Chem. Res. Toxicol. 2018, 31, 251−258
Article
Chemical Research in Toxicology Table 2. Little Cigar and Cigarillo Ad Lib Puff Topographya
a
parameter
little cigar
cigarillo
number of puffs* total time to smoke (s)* average puff volume (mL)* puff velocity (ml/s) puff duration (s)* inter puff interval (s) total puff volume (mL) *
9.8 (6.2−13.4; 1.8) 239.3 (129.8−348.9; 54.7) 41.5 (34.2−48.8; 3.7) 22.0 (18.2−25.8; 1.9) 2.0 (1.6−2.3; 0.2) 20.8 (16.6−25.1; 2.1) 399.0 (123.4−674.7; 137.8)
23.1 (19.7−26.5; 1.7) 607.4 (504.9−709.8; 51.2) 57.0 (50.1−63.8; 3.4) 23.6 (20.1−27.2; 1.8) 2.8 (2.5−3.1; 0.2) 24.5 (20.5−28.5; 2.0) 1,252.3 (994.5−1,510.2; 128.9)
* indicates significant difference between groups.
among people who ordinarily use either filtered little cigars or cigarillos. Mouth Level Exposure to Toxins (MSS Analysis). As presented in Table 1, both cigarillos and little cigar MSS contained volatile and semivolatile compounds that are listed in the FDA Harmful or Potentially Harmful list of toxicants.19 Qualitatively, the composition of the MSS of little cigar and cigarillos was similar. Quantitatively, the MSS from the cigarillo contained significantly more toxicants than the smoke of the little cigar (Table 4). Ten of the 11 toxicants were significantly greater in cigarillo MSS compared to the smoke of little cigar. Only the level of nicotine was not significantly different in the MSS of the cigarillo (2.3 mg) compared with the little cigars (1.8 mg) (p < 0.10 level). Furthermore, toxicant quantities in the MSS differed as a function of smoking topography such that participants that smoked more intensively were exposed to more toxicants than those that smoked less intensively. Specifically, there were significant correlations for total puff volume and all analyzed compounds (SVOCs and VOCs) for both cigarillo (all r values were >0.67, all p-values were 0.58 and all p-values were 10 ppm) in exhaled CO. In contrast, in a recent study of directed cigar smoking where inhalation was not allowed minimal (
