Globally, tobacco use accounts for 4.9 million deaths each year. These deaths are caused by inhaled smoke toxicants. Extensive research describes cigarette smoke toxicant content (or yield), a vital link to understanding user toxicant exposure. However, millions of people use waterpipes (WP) to smoke tobacco. WP tobacco smoking may also be deadly, though little is known about WP smoke toxicant yield. A WP (hookah, shisha) has a hose, water bowl, body, and a head filled with sweetened and flavored tobacco that is heated with charcoal. WP tobacco smoking is increasing in the U.S., especially among college students. Relative to one cigarette, one WP use episode can generate 100 times the smoke. Current technology demands that, if we are to learn about WP smoke, we must use machines to generate it. Machine-generated smoke may limit validity because generation of WP smoke involves several key variables that differ by user and use episode which cannot be standardized in the analytical lab. This response to PAR-08-212 integrates mechanical engineering, chemistry, and clinical behavioral pharmacology to develop and test an unobtrusive WP smoke sampling instrument for the purpose of assessing the toxicant content of smoke produced in the natural environment.
The specific aims are to: 1) Characterize a real-time WP smoke sampling device (Years 1-3). We have developed a prototype device that measures puff topography and samples WP smoke in real- time (REALTIME). Because particle deposition in the device may alter smoke toxicant content, correction factors need to be developed to infer true toxicant content from that measured. We will therefore measure toxicant-specific deposition fractions in the device, in particular for: particle number, particle mass, nicotine, tobacco-specific nitrosamines, and polycyclic aromatic hydrocarbons. 2) Evaluate REALTIME design options in the clinical laboratory (Years 1 and 2). Two design options, placement of the smoke sampler and the percentage of smoke sampled, involve tradeoffs between accurate measurement of toxicant content and realistic smoker behavior. We propose two controlled clinical laboratory studies to inform design option choice, with Study 1 addressing sampler placement (bowl or mouthpiece) and Study 2 addressing percentage of smoke sampled (2, 5, or 10%). The preferred option maximizes realistic smoke toxicant analysis while minimizing effects on smoker behavior. 3) Evaluate REALTIME in the natural environment (years 4 and 5). REALTIME will be attached to WPs used by consenting individual and groups of WP cafi patrons. The study will demonstrate REALTIME’s use in natural settings and examine the relationship between the number of WP users and tobacco temperature and WP smoke toxicant yield. In sum, the technology and methodology developed in this project will enable valid analysis of WP smoke toxicant content. This interdisciplinary project addresses an emerging public health threat and is directly relevant to the NIH mission and wholly responsive to PAR-08-212.

Public Health Relevance

This project is relevant to public health because waterpipe tobacco smoking is a little-understood but rapidly emerging strain in the nation’s tobacco use epidemic. The project will inform nascent efforts to prevent waterpipe tobacco smoking from contributing substantially to tobacco’s morbidity and mortality by developing and validating the technology necessary to learn about waterpipe smoke toxicant content in natural settings. For cigarette smoking, valid and reliable information regarding smoke toxicant content has been used effectively to support tobacco use prevention and control programs;this project seeks similar positive outcomes for another potentially lethal form of tobacco use.

Funding source: US National Cancer Institute R01 DA025659 

Globally, tobacco use accounts for 4.9 million deaths each year, including 400,000 in the U.S. These deaths are caused by inhaled smoke toxicants like carcinogens, carbon monoxide (CO), and nitric oxide (NO). Another smoke toxicant, nicotine, produces dependence with prolonged use. Cigarette smoke toxicant content and smoker toxicant exposure has been well characterized, as have the subjective and cardiovascular effects of cigarette smoking. However, in the U.S. and globally, millions of people use waterpipes (hookah or shisha) to smoke tobacco: the smoker fills the head with sweetened and flavored tobacco, covers it with perforated aluminum foil, and tops the foil with lit charcoal. Charcoal and tobacco smoke pass to the user via a half-filled water bowl, hose, and mouthpiece. Waterpipe tobacco smoking is increasing in the U.S., especially among college students for whom prevalence rates may be 15-20%. Relative to one cigarette, one waterpipe use episode can generate 100 times the smoke, with user toxicant exposure, effects, and smoke toxicant content that are largely unknown. These outcomes may depend upon an individual’s use frequency and whether the individual uses the waterpipe alone or with a group. This project combines clinical laboratory methods, analytical chemistry, and cellular biology to achieve three specific aims. 1) Learn about individual waterpipe user toxicant exposure, effects, and smoke toxicant content. In two separate sessions, 130 waterpipe users (65 reporting 2-5 uses/month and 65 reporting > 21 uses/month) will use a waterpipe loaded with preferred brand/flavor of waterpipe tobacco or placebo. Outcome measures include CO and NO, plasma nicotine, subjective, cardiovascular, and pulmonary response, and puff topography (puff number, volume, duration, and interpuff interval). Topography records will be replayed in an analytical laboratory to study smoke toxicant content and cytotoxicity/mutagenicity. 2) Learn how group use influences waterpipe toxicant exposure, effect, and smoke toxicant content. In an observational study, trained staff will use rigorous sampling and data collection procedures to study group waterpipe tobacco smoking in local cafs. In a laboratory study informed by observational study results, 65 waterpipe- sharing groups will use a waterpipe in the laboratory as a group in one session, and as individuals in another session, and user toxicant exposure and effects, and smoke toxicant content will be assessed as in Study 1. 3) Compare the toxicant exposure and effects of waterpipe tobacco smoking and cigarette smoking. In two sessions, 100 waterpipe users who also smoke cigarettes will either use a waterpipe or smoke a cigarette; outcome measures include exposure to CO, NO, and nicotine, as well as cardiovascular, respiratory, and subjective effects. Waterpipe use is disturbingly common among U.S. young adults. More information is needed about waterpipe effects, and it can be obtained from clinical laboratory studies and smoke toxicant analysis. This information is necessary to understand this potentially dangerous behavior, while shaping knowledge, opinions, and attitudes in a way that enhances public health. This project is relevant to public health because waterpipe tobacco smoking is a little-understood but rapidly emerging strain in the nation’s tobacco use epidemic. The project will inform nascent efforts to prevent waterpipe tobacco smoking from contributing substantially to tobacco’s morbidity and mortality by revealing the user toxicant exposure, subjective, cardiovascular, and pulmonary effects, and cytogenicity and mutagenicity of waterpipe tobacco smoke produced by individuals and groups; it will also address frequent but probably erroneous statements regarding waterpipe filtering and lower toxicant levels relative to cigarette smoke. The positive health impact of this type of research on tobacco cigarette smoking is well-documented; this project seeks similar positive outcomes on another potentially lethal form of tobacco use.

Funding source: US National Cancer Institute R01 CA120142