Design and Validation of a Research-Grade Waterpipe Equipped With Puff Topography Analyzer.

INTRODUCTION: Worldwide, commercially available waterpipes vary widely in design and durability, including differences in fabrication materials, degree of leak-tight fit, and flow path diameter. Little is known about how the components of the waterpipe may influence puffing behavior and user's exposure to toxins. To systematically evaluate exposure, it is necessary to use a standardized research-grade waterpipe (RWP) when conducting clinical and laboratory-based trials. METHODS: We developed a RWP that is configured with an in-line topography system which allows real-time measurement and recording of the smoke volume drawn through the RWP. The RWP was calibrated across the flow rate range expected for waterpipe tobacco smoking and the calibration was verified for known puff volumes using a smoking machine. Operation of the RWP was qualified in a cohort of experienced waterpipe smokers, each smoker using the RWP ad libitum in a laboratory setting while smoker topography and subjective effects data were collected. RESULTS: RWP machine smoking was highly reproducible and yielded puff volumes that agreed well with true values. User acceptance was comparable, and puffing behavior was similar in pattern, with more frequent puffing in the beginning of the session, but significantly different in intensity from that used to estimate the majority of toxicant exposure reported in the literature. CONCLUSIONS: The RWP operates with known precision and accuracy and is well accepted by experienced smokers. This tool can be used to determine the extent to which puffing behaviors are affected by the waterpipe design, components, and/or accessories, tobacco nicotine content, sweet flavorings and/or additives known to increase addictiveness. IMPLICATIONS: This study describes a standardized RWP, equipped with a puffing topography analyzer, which can operate with known precision and accuracy, and is well-accepted by experienced smokers in terms of satisfaction and reward. The RWP is an important tool for determining if puffing behaviors, and thus estimated toxin exposures, are affected by the waterpipe design, components, and/or accessories, tobacco nicotine content, sweet flavorings, and/or additives that are known to increase addictiveness.

Comparison of True and Smoothed Puff Profile Replication on Smoking Behavior and Mainstream Smoke Emissions.

To estimate exposures to smokers from cigarettes, smoking topography is typically measured and programmed into a smoking machine to mimic human smoking, and the resulting smoke emissions are tested for relative levels of harmful constituents. However, using only the summary puff data--with a fixed puff frequency, volume, and duration--may underestimate or overestimate actual exposure to smoke toxins. In this laboratory study, we used a topography-driven smoking machine that faithfully reproduces a human smoking session and individual human topography data (n = 24) collected during previous clinical research to investigate if replicating the true puff profile (TP) versus the mathematically derived smoothed puff profile (SM) resulted in differences in particle size distributions and selected toxic/carcinogenic organic compounds from mainstream smoke emissions. Particle size distributions were measured using an electrical low pressure impactor, the masses of the size-fractionated fine and ultrafine particles were determined gravimetrically, and the collected particulate was analyzed for selected particle-bound, semivolatile compounds. Volatile compounds were measured in real time using a proton transfer reaction-mass spectrometer. By and large, TP levels for the fine and ultrafine particulate masses as well as particle-bound organic compounds were slightly lower than the SM concentrations. The volatile compounds, by contrast, showed no clear trend. Differences in emissions due to the use of the TP and SM profiles are generally not large enough to warrant abandoning the procedures used to generate the simpler smoothed profile in favor of the true profile.

Exposure to and deposition of fine and ultrafine particles in smokers of menthol and nonmenthol cigarettes.

INTRODUCTION: Research on the deposition of mainstream smoke particulate in the respiratory tract of smokers is needed to understand how exposure may vary based on cigarette menthol content. METHODS: We conducted a nine-participant crossover study in which smokers were randomly assigned to cigarettes differing primarily in menthol content. Participants smoked the test cigarettes ad libitum for one week, provided spot urine samples, and then smoked four test cigarettes in a laboratory session; this was repeated for the other test cigarette in week two. Fine and ultrafine particulate matter in exhaled breath were characterized, and smoking behavior was monitored. Participant-specific mainstream smoke, generated using each participant's topography data, was characterized. During home smoking, participants collected their spent test cigarette butts for estimates of mouth-level exposures (MLE) to mainstream nicotine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). RESULTS: Participant-specific mainstream smoke NNK was higher (39%) and daily MLE to NNK was also higher (52%) when participants smoked the menthol cigarette. Nicotine was not significantly different. Participants retained more ultrafine particulate (43%) and fine particulate benzo(a)pyrene (43%) when smoking the menthol cigarette. There were no significant differences in the levels of urinary biomarkers for nicotine, NNK, or pyrene. CONCLUSION: This study demonstrates the use of noninvasive real-time techniques to measure exposure differences between cigarettes differing primarily in menthol content. Differences between NNK exposure, ultrafine particle and benzo(a)pyrene deposition, and smoking behavior were observed. Additional research using these techniques with cigarettes that differ only in menthol content is required to unequivocally attribute the exposure differences to presence or absence of menthol.

Custom Mentholation of Commercial Cigarettes for Research Purposes.

In the U.S. menthol remains the sole permitted characterizing cigarette flavor additive in part because efforts to link menthol cigarette use to increased tobacco-related disease risk have been inconclusive. To perform definitive studies, cigarettes that differ only in menthol content are required, yet these are not commercially available. We prepared research cigarettes differing only in menthol content by deposition of L-menthol vapor directly onto commercial nonmenthol cigarettes, and developed a method to measure a cigarette's menthol and nicotine content. With our custom-mentholation technique we achieved the desired moderately high menthol content (as compared to commercial brands) of 6.7 ± 1.0 mg/g (n = 25) without perturbing the cigarettes' nicotine content (17.7 ± 0.7 mg/g [n = 25]). We also characterized other pertinent attributes of our custom-mentholated cigarettes, including percent transmission of menthol and nicotine to mainstream smoke and the rate of loss of menthol over time during storage at room temperature. We are currently using this simple mentholation technique to investigate the differences in human exposure to selected chemicals in cigarette smoke due only to the presence of the added menthol. Our cigarettes will also aid in the elucidation of the effects of menthol on the toxicity of tobacco smoke.