Comparison between the mainstream smoke of eleven RYO tobacco brands and the reference tobacco 3R4F

Tobacco Constituents, Flavorants, and Paper Permeability of Factory-Made and Roll-Your-Own Cigarettes on the Australian Market

INTRODUCTION

Roll-your-own (RYO) tobacco is a popular choice in Australia, with some people who smoke finding these products more attractive than factory-made cigarettes (FMC). Differences in visual and tactile properties and in the feel and taste of the smoke may contribute to this attractiveness. These differences may be driven by variation in tobacco constituents and wrapping paper permeability. However, to date, there has been no comparison of RYO and FMC products on the Australian market.

AIMS AND METHODS

Chemical constituents, pH, flavorants, and paper permeability were compared in unburned RYO tobacco and tobacco from FMC. RYO and FMC products from matched brands were compared, as were products from the most popular FMC and RYO brands on the Australian market in 2018.

RESULTS

RYO tobacco had higher moisture and humectant content (glycerol and propylene glycol) than FMC tobacco. RYO tobacco also had higher amounts of total and reducing sugars and lower nicotine when comparing the most popular brands. RYO papers were less permeable than FMC papers. Both RYO and FMC tobacco contained many chemicals identified as flavorants, including fourteen with known potential health risks. For most measured constituents and flavorants, RYO tobaccos had more in common with other RYO than FMC, with the commonalities remaining even when matched brands were compared.

CONCLUSIONS

Higher levels of moisture, humectants, and sugars in Australian RYO tobacco compared to FMC may be increasing attractiveness of RYO by reducing the harsh taste of the smoke and increasing the moist feel of the tobacco.

IMPLICATIONS

While price is the main factor driving the use of RYO tobacco, some people who smoke find these products more attractive. This study has shown that Australian RYO tobacco contains higher amounts of glycerol, propylene glycol, and sugars than FMC. These chemicals may be improving the taste of the tobacco, as well as creating a moist feel that is falsely perceived as indicating that the tobacco is "fresh" and "less chemically." Ironically, it may be that higher amounts of some added chemicals in RYO contribute to false perceptions of a more natural and less harmful product.

Assessment of heavy metal levels in roll-your-own cigarette and water pipe tobacco blends

The increased consumption of roll-your-own (RYO) cigarettes and water pipe (hookah), both globally and in Bulgaria, necessitated the current investigation aimed at the assessment of heavy metal levels in the tobacco blends used in those products. The concentrations of Mn, Zn, Cu, Cd, Pb, and Ni were determined by AAS in five brands of RYO tobacco (R1-R5) and seven brands of water pipe tobacco (W1- W7), all distributed on Bulgarian market. The average heavy metal contents (mg/kg) in the two types of tobacco blends, RYO and water pipe, respectively, were as follows: Mn - 214.20 and 37.89; Zn - 31.90 and 134.87; Cu - 12.06 and 10.07; Cd - 0.80 and 1.33; Pb - 1.60 and 3.57; Ni - 1.36 and 0.80. RYO cigarette tobaccos contained higher concentration of Mn, Cu and Ni, while water pipe tobaccos - Zn, Cd and Pb. Strong correlations were found between Cu and Zn (r=0.81), Cu and Cd (r=0.90) in RYO tobacco blends, and between Cu and Zn (r=0.86) - in water pipe blends, respectively. The results from the study give reason to recommend that this information be provided to the consumers, who consider the regarded tobacco products as a safer alternative to conventional cigarettes.

Should IQOS Emissions Be Considered as Smoke and Harmful to Health? A Review of the Chemical Evidence

The chemical evidence that IQOS emissions fit the definition of both an aerosol and smoke, and that IQOS and potentially other heated tobacco products (HTPs) pose some harmful health threats from the range of compounds released even at somewhat lower concentrations is reviewed. Further, we address the yields of harmful and potentially harmful compounds (HPHCs), including polycyclic aromatic hydrocarbons (PAHs), and the constituents of IQOS emission that are diagnostic of pyrolysis to provide information on the temperatures reached in IQOS tobacco sticks. The HPHCs present in IQOS emissions are the same as in conventional cigarette smoke (CCs), analogous to emissions from earlier generation of HTPs classed as smoke. However, Philip Morris International (PMI) studies have to some degree underestimated IQOS aerosol HPHC yields, which are a factor of between 3.2 and 3.6 higher when expressed on a tobacco rather than an IQOS stick basis compared to the reference 3R4F cigarette. Further, IQOS emissions contain carbon particles, which fit definition of both aerosol and smoke. Continual reheating of deposited tar in the IQOS device will occur with real-life use, likely leading to generation of even higher concentrations of HPHCs and particulate matter. Despite IQOS not exceeding 350 °C, local hot spots could exist, causing formation of species (phenol/cresols, PAHs). It is recommended that the impact of repeated use to determine the levels of black carbon (insoluble organic matter) in the particulate matter, and the extent to which compounds in IQOS emissions are formed by pyrolysis need to be assessed rigorously. To address whether uneven temperature profiles in heat sticks can lead to potential hot spots that could, for example, lead to PAH formation, it is recommended that pyrolysis studies on tobacco and other constituents of HTPs are required in conjunction with more effort on heating tobacco blends under controlled temperature/time conditions.

Comparative study of the smoke emissions from fine-cut tobacco blends depending on the characteristics of the used RYO/MYO cigarette materials

The European tobacco market has experienced significant changes in the last years – with the introduction of new tobacco products and the increased consumption of certain traditional products. Recent research of fine-cut tobacco blends (for RYO and MYO cigarettes) in Bulgaria is very limited, which substantiates the current comparative investigation of the smoke emissions of RYO tobaccos, accounting for the used materials (cigarette paper and filter tips). Three variants of laboratory-made cigarettes from five tobacco blends (A -E) were analyzed: variant I – with ready-to-use cigarette tubes; variant II – with gummed cigarette paper and filter tips with diameter 8 mm and length 15 mm; variant III – with the same cigarette paper and filter tips with diameter 6 mm and length 20 mm. The highest levels of smoke emissions were found for variant I and the minimal -for variant III, with no uniform trend between the blends. The smoke emissions from the analyzed RYO tobaccos exceeded the legal limits for commercial cigarettes, except for nicotine from blends B and D, and CO from blend D in variant III. In all variants, a strong correlation between the studied smoke emissions was observed -positive for nicotine/tar and tar/CO, and negative for nicotine/CO.

The Emission of VOCs and CO from Heated Tobacco Products, Electronic Cigarettes, and Conventional Cigarettes, and Their Health Risk

The differences in aerosol composition between new tobacco types (heated tobacco products and electronic cigarettes) and conventional cigarettes have not been systematically studied. In this study, the emissions of volatile organic compounds (VOCs), carbon monoxide (CO), nicotine, and tar from heated tobacco products (HTPs), electronic cigarettes (e-cigarettes) and conventional cigarettes were compared, and their health risks were evaluated by applying the same smoking regime and a loss mechanism of smoking. Twenty VOCs were identified in aerosols from HTPs, 18 VOCs were identified in aerosols from e-cigarettes, and 97 VOCs were identified in aerosols from cigarettes by GC–MS and HPLC analysis. The concentrations of total VOCs (TVOCs) emitted by the three types of tobacco products decreased as follows: e-cigarettes (795.4 mg/100 puffs) > cigarettes (83.29 mg/100 puffs) > HTPs (15.65 mg/100 puffs). The nicotine content was 24.63 ± 2.25 mg/100 puffs for e-cigarettes, 22.94 ± 0.03 mg/100 puffs for cigarettes, and 8.817 ± 0.500 mg/100 puffs for HTPs. When using cigarettes of the same brand, the mass concentrations of VOCs, tar, and CO emitted by HTPs were approximately 81.2%, 95.9%, and 97.5%, respectively, lower than the amounts emitted by cigarettes. The health risk results demonstrated that the noncarcinogenic risk of the three types of tobacco products decreased as follows: cigarettes (3609.05) > HTPs (2449.70) > acceptable level (1) > e-cigarettes (0.91). The lifetime cancer risk (LCR) decreased as follows: cigarettes (2.99 × 10⁻⁴) > HTPs (9.92 × 10⁻⁵) > e-cigarettes (4.80 × 10⁻⁵) > acceptable level (10⁻⁶). In general, HTPs and e-cigarettes were less harmful than cigarettes when the emission of VOCs and CO was considered.

Future intentions and beliefs about roll-your-own cigarettes in adolescents

OBJECTIVE

To determine the predisposition to use roll-your-own (RYO) cigarettes and the beliefs about RYO cigarettes of all the students of 3°-4° of ESO during the years 2016-17 and 2018-19. A cross-sectional study.

SETTING

Bisaura High School from Sant Quirze de Besora. Primary Health Care in the Catalan Health Institute, Catalunya, Spain.

PARTICIPANTS

111 3rd and 4th of ESO (14-16 years).

MAIN MEASUREMENTS

Dependent variables used were future intentions of smoking and beliefs regarding RYO cigarettes. Independent variables were sex, course and ever smoked. The prevalence of the different dependent variables was described and compared according to the different independent variables with Pearson's Khi-square test.

RESULTS

26.6% of the adolescents intended to smoke in the future of which 17.4% intended to smoke RYO cigarettes and 13.8% manufactured cigarettes (MC). Around 30% of adolescents express at least one wrong belief regarding RYO cigarettes. For example, the 26.7% believed that smoking RYO cigarettes generated less addiction than MC and the 32.1% that was less harmful. Those who had smoked at some time in their life had a greater intention to smoke in the future (54.5%), to smoke MC (27.3%) and RYO cigarettes (40.9%) than those who had never smoked (7.7%, 4.6% and 1.5% respectively) (p<0.005). Some misconceptions differed depending on whether adolescents had ever smoked in life, sex and course. The boys believed that smoking RYO cigarettes was more natural than smoking MC (p<0.005).

CONCLUSIONS

Educational activities to improve the information that young people have regarding RYO cigarettes are needed.

Quantification of nitromethane in mainstream smoke using gas chromatography and tandem mass spectrometry

Nitromethane is a volatile organic compound categorized as a Group 2B carcinogen by the International Agency for Research on Cancer. It has been detected in mainstream cigarette smoke, but few reliable methods have been reported for accurate quantification. We developed, a sensitive, selective, fully validated method for the targeted determination of nitromethane in mainstream tobacco smoke in ten U.S. domestic brands and two quality control materials (3R4F and CM6). The vapor phase portion of machine-generated cigarette mainstream smoke, under modified ISO 3308:2000 regime (ISO) and modified intense regime (HCI), from single cigarettes was collected using airtight polyvinylfluoride sampling bags. The bags' contents were extracted using methanol containing an isotopically labeled internal standard followed by gas chromatography-tandem mass spectrometry. This approach is sufficiently sensitive to measure nitromethane levels in the nanogram range, with a method limit of detection of 72.3 ng/cig. Within-product variability estimated from the replicate analysis of 10 products ranged from 4.6%-16.3% (n = 6) over the two different smoking regimes, and method reproducibility estimated from two products used as quality control materials (3R4F and CM6) yielded intermediate precision values ranging from 16.6 to 20.8% (n = 20). Under HCI, nitromethane yields in machine-generated cigarette smoke from ten different domestic cigarette products ranged from 3.2 to 12 μg/cig; under ISO yields ranged from 1.6 to 4.9 μg/cig under standardized smoking machine conditions. Nitromethane yields are related to both the smoke regime (blocking of vent holes, puff duration and puff volume) and the heterogeneity of tobacco mixtures. This method provides a selective and fully validated technique to accurately quantify nitromethane in mainstream cigarette smoke, with minimal waste generation. It is an improvement over previous methods with regards to specificity, throughput, and simplicity of the sample collection process.

Effects of cigarette smoke on the administration of isoniazid and rifampicin to macrophages infected with Mycobacterium tuberculosis

BACKGROUND

Smoking is a cause behind many diseases, including tuberculosis, and it is a risk factor for tuberculosis infection and mortality. Moreover, smoking is associated with a poor tuberculosis treatment outcome.

OBJECTIVES

In this study, we focus on the effects of cigarette smoke on an infected cell culture treated with anti-tuberculosis drugs.

MATERIALS AND METHODS

Cytotoxicity on THP-1, J774A.1 and MH-S cell lines and growth of Mycobacterium tuberculosis exposed to a reference or a commercial cigarette was evaluated. THP-1 cell line was exposed to cigarette smoke, infected with Mycobacterium tuberculosis and treated with anti-tuberculosis drugs. Apoptosis and death cell were also tested on M. bovis BCG infected cells. Minimal inhibitory concentrations of anti-tuberculosis drugs were analyzed.

RESULTS

All cells lines showed viability values higher than 80% when exposed to cigarette smoke extract. However, THP-1 cell line infected with M. bovis BCG and exposed to Marlboro cigarette smoke showed up to a 54% reduction of apoptotic cells than cells unexposed to smoke. M. tuberculosis exposed to Marlboro cigarette smoke for 11 days had an optical density 16% lower than unexposed bacteria. When cells were infected with M. tuberculosis, the intracellular recovery of CFUs showed up to a 0.66 log reduction in cells exposed to cigarette smoke extract because of a potential impairment in the phagocytosis. Macrophages treated with drugs showed up to a 2.55 log reduction in the intracellular load burden compared with non-treated ones. Despite poor treatment outcome on TB smoker patients, minimal inhibitory concentration of rifampicin increased only 2-fold in M. tuberculosis exposed to cigarette smoke.

CONCLUSION

Smoking interferes with tuberculosis treatment impairing the immunity of the host.

The Effect of Temperature and Time of the Hydrothermal Treatment in the SBA-15 Synthesis Process on the Structure and Textural Properties and the Ability to Reduce the Evolution of Tars in Tobacco Smoking

Different SBA-15 (SBA, Santa Barbara Amorphous) materials were synthetized at different temperature and time during of the hydrothermal treatment. The obtained SBA-15 were characterized by N2 adsorption isotherms, scanning electron microscopy (SEM), X-ray diffraction (DRX), and density in order to establish the influence of these variables on their properties. Mixtures of the obtained catalysts with 3R4F tobacco were prepared and smoked under the ISO 3308 conditions. Temperature of the hydrothermal treatment slightly affects the tars that evolved in the smoking process of the corresponding catalyst tobacco mixtures. Contrarily, the time of the hydrothermal treatment has a marked effect on the reductions of toxic compounds in the smoke. Developed porosity has a positive correlation with the observed tar reduction, whereas the apparent density has a negative correlation with the reduction in toxicity. Moreover, the removal of the supernatant liquors during the hydrothermal treatment does not strongly modify the properties of the materials and may represent an interesting simplification of the process.

A 6-month systems toxicology inhalation study in ApoE-/- mice demonstrates reduced cardiovascular effects of E-vapor aerosols compared with cigarette smoke

Smoking cigarettes is harmful to the cardiovascular system. Considerable attention has been paid to the reduced harm potential of alternative nicotine-containing inhalable products such as e-cigarettes. We investigated the effects of E-vapor aerosols or cigarette smoke (CS) on atherosclerosis progression, cardiovascular function, and molecular changes in the heart and aorta of female apolipoprotein E-deficient (ApoE^-/-) mice. The mice were exposed to aerosols from three different E-vapor formulations: 1) carrier (propylene glycol and vegetable glycerol), 2) base (carrier and nicotine), or 3) test (base and flavor) or to CS from 3R4F reference cigarettes for up to 6 mo. Concentrations of CS and base or test aerosols were matched at 35 µg nicotine/L. Exposure to CS, compared with sham-exposed fresh air controls, accelerated atherosclerotic plaque formation, whereas no such effect was seen for any of the three E-vapor aerosols. Molecular changes indicated disease mechanisms related to oxidative stress and inflammation in general, plus changes in calcium regulation, and altered cytoskeletal organization and microtubule dynamics in the left ventricle. While ejection fraction, fractional shortening, cardiac output, and isovolumic contraction time remained unchanged following E-vapor aerosols exposure, the nicotine-containing base and test aerosols caused an increase in isovolumic relaxation time similar to CS. A nicotine-related increase in pulse wave velocity and arterial stiffness was also observed, but it was significantly lower for base and test aerosols than for CS. These results demonstrate that in comparison with CS, E-vapor aerosols induce substantially lower biological responses associated with smoking-related cardiovascular diseases.NEW & NOTEWORTHY Analysis of key urinary oxidative stress markers and proinflammatory cytokines showed an absence of oxidative stress and inflammation in the animals exposed to E-vapor aerosols. Conversely, animals exposed to conventional cigarette smoke had high urinary levels of these markers. When compared with conventional cigarette smoke, E-vapor aerosols induced smaller atherosclerotic plaque surface area and volume. Systolic and diastolic cardiac function, as well as endothelial function, were further significantly less affected by electronic cigarette aerosols than conventional cigarette smoke. Molecular analysis demonstrated that E-vapor aerosols induce significantly smaller transcriptomic dysregulation in the heart and aorta compared with conventional cigarette smoke.

Comparison of TSNAs concentration in saliva according to type of tobacco smoked

OBJECTIVE

To compare tobacco-specific nitrosamines (TSNAs) measured in saliva according to different types of tobacco smoked in a sample of smokers of the city of Barcelona (Spain).

METHODS

We used data from a cross-sectional study of a sample of the adult smoking population of Barcelona, Spain in 2013-2014 (n = 165). We classified smokers in five groups according to the type of tobacco smoked: a) manufactured cigarettes only, b) roll-your-own (RYO) cigarettes only, c) dual smokers (both manufactured and RYO cigarettes), d) manufactured plus other types of tobacco products different from RYO and e) other types of tobacco products different from manufactured and RYO cigarettes. We calculated the geometric mean (GM) and geometric standard deviation (GSD) of TSNAs concentration in saliva (pg/mL), including N'-nitroaonornicotine (NNN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) according to the five tobacco groups. We also described all TSNAs concentration in each tobacco group stratified by the number of cigarettes smoked per day.

RESULTS

Smokers from the RYO cigarette group had higher TSNAs concentration than smokers from the manufactured cigarette group: 13 pg/mL vs 4.9 pg/mL of NNN, 1.9 pg/mL vs 1.7 pg/mL in NNK and 1.1 pg/mL vs 0.9 pg/mL of NNAL. There were significant differences in NNN concentrations between smokers of RYO vs manufactured cigarettes. The higher the number of cigarettes smoked, the higher the TSNAs concentrations. After adjusted by number of cigarettes smoked, there were not statistically significant differences in TSNAs between RYO and manufactured cigarettes.

CONCLUSIONS

Our data shows that RYO cigarette is at least as hazardous as manufactured cigarettes. Regulating RYO tobacco prices could be an effective strategy to control tobacco use.

Mainstream smoke constituents and in vitro toxicity comparative analysis of 3R4F and 1R6F reference cigarettes

A new Kentucky reference cigarette, 1R6F, has been manufactured to replace the depleting 3R4F reference cigarette. The 3R4F Kentucky reference cigarettes have been widely used as monitor or comparator cigarettes for mainstream smoke analysis and in vitro and in vivo toxicological data of cigarettes and novel tobacco products. Both reference cigarettes were analyzed in the same laboratory during the same period of time with the goal of performing a comparison of 3R4F and 1R6F. On the basis of the results obtained from aerosol chemistry and in vitro assays, we consider that the 1R6F reference cigarette is a suitable replacement for the 3R4F reference cigarette as a comparator/monitor cigarette. Its specific use as a comparator for novel tobacco products was checked on the basis of a comparative test with the Tobacco Heating System 2.2 as an example.

Delivery efficiencies of constituents of combustion-derived aerosols across the air-liquid interface during in vitro exposures

In vitro aerosol exposure of epithelial cells grown at the air-liquid interface is an experimental methodology widely used in respiratory toxicology. The exposure depends to a large part on the physicochemical properties of individual aerosol constituents, as they determine the transfer kinetics from the aerosol into the cells. We characterized the transfer of 70 cigarette smoke constituents from the smoke into aqueous samples exposed in the Vitrocell® 24/48 aerosol exposure system. The amounts of these compounds in the applied smoke were determined by trapping whole smoke in N,N-dimethylformamide and then compared with their amounts in smoke-exposed, phosphate-buffered saline, yielding compound specific delivery efficiencies. Delivery efficiencies of different smoke constituents differed by up to five orders of magnitude, which indicates that the composition of the applied smoke is not necessarily representative for the delivered smoke. Therefore, dose metrics for in vitro exposure experiments should, if possible, be based on delivered and not applied doses. A comparison to literature on in vivo smoke retention in the respiratory tract indicated that the same applies for smoke retention in the respiratory tract.

Thermal desorption comprehensive two-dimensional gas chromatography coupled to time of flight mass spectrometry for vapour phase mainstream tobacco smoke analysis

A thermal desorption comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (TD-GC×GC-TOFMS) method has been developed for the analysis of mainstream tobacco smoke (MTS) vapour phase (VP). The selection process of the sample introduction approach involved comparing the results obtained from three different approaches: a) use of gas sampling bag followed by SPME (Tedlar®-SPME), b) gas sampling bag followed by TD (Tedlar®-TD), and c) sampling directly on TD sorbents (Direct-TD). Six different SPME fibers and six different TD sorbent beds were evaluated for the extraction capacities in terms of total number of peaks and related intensities or peak areas. The best results were obtained for the Direct-TD approach using Tenax TA/Carbograph1TD/Carboxen1003 sorbent tubes. The optimisation of TD tube desorption parameters was carried out using a face-centered central composite experimental design and resulted in the use of the Tenax TA/Carbograph 1TD/Carboxen 1003 sorbent with a 7.5min desorption time, a 60mL/min tube desorption flow, and a 250°C tube desorption temperature. The optimised method was applied to the separation of MTS-VP constituents, with 665 analytes detected. The method precision ranged from 1% to 15% for over 99% of identified peak areas and from 0% to 3% and 0% to 1% for both first (1tR) and second (2tR) dimension retention times, respectively. The method was applied to the analyses of two cigarette types differing in their filter construction. Principal component analysis (PCA) allowed a clear differentiation of the studied cigarette types (PC1 describing 94% of the explained variance). Supervised Fisher ratio analysis permitted the identification of compounds responsible for the chemical differences between the two sample types. A set of 91 most relevant compounds was selected by applying a Fisher ratio cut-off approach and most of them were selectively removed by one of the cigarette filter types.

Little Cigars vs 3R4F Cigarette: Physical Properties and HPHC Yields

Objective

Our objective was to characterize physical properties and semivolatile harmful and potentially harmful constituent yields in the mainstream smoke (MSS) of 4 popular little cigars compared to the 3R4F reference cigarette.

Methods

We used the ISO and Canadian Intense Regimen protocols to generate MSS for Cheyenne (Full Flavor and Menthol) and Swisher Sweets (Original and Sweet Cherry) little cigars; and the 3R4F. We examined physical properties such as length, tobacco filler mass, pressure drop, and ventilation for each product. Nicotine, benzo[a]pyrene, and tobacco-specific nitrosamine (TSNA) yields were determined in the MSS.

Results

Little cigars were longer (~15mm), contained more tobacco filler (100-200 mg), and had a higher pressure drop (~1.3X) compared to the 3R4F. Ventilation holes were found only on the filter paper of the 3R4F. Nicotine transmitted to the MSS was similar for all products under the intense smoking protocol. The highest yields of TSNAs and benzo(a)pyrene were measured for the little cigars.

Conclusions

Little cigars may deliver similar levels of nicotine but higher levels of carcinogens to the MSS compared to cigarettes. Thus, previous reports on the toxicity of tobacco smoke based on cigarettes might not apply to little cigar products.

Reduction of tobacco smoke components yield in commercial cigarette brands by addition of HUSY, NaY and Al-MCM-41 to the cigarette rod

The effect of two zeolites, HUSY, NaY and a mesoporous synthesized Al-MCM-41 material on the smoke composition of ten commercial cigarettes brands has been studied. Cigarettes were prepared by mixing the tobacco with the three powdered materials, and the smoke obtained under the ISO conditions was analyzed. Up to 32 compounds were identified and quantified in the gas fraction and 80 in the total particulate matter (TPM) condensed in the cigarettes filters and in the traps located after the mouth end of the cigarettes. Al-MCM-41 is by far the best additive, providing the highest reductions of the yield for most compounds and brands analyzed. A positive correlation was observed among the TPM and nicotine yields with the reduction obtained in nicotine, CO, and most compounds with the three additives. The amount of ashes in additive free basis increases due to the coke deposited on the solids, especially with Al-MCM-41. Nicotine is reduced with Al-MCM-41 by an average of 34.4% for the brands studied (49.5% for the brand where the major reduction was obtained and 18.5 for the brand behaving the worst). CO is reduced by an average of 18.6% (ranging from 10.3 to 35.2% in the different brands).