Hookah Additive Research to Inform Product Standards

This clinical trial evaluates how the content of waterpipe (WP) tobacco affects the appeal, puffing behavior, and toxicity of WP tobacco smoking. The data from the proposed study will provide direct links between WP tobacco's primary additives (sugars and humectants), CO and nicotine biomarkers, smoker preferences, perceptions of harm and puffing behaviors, and the subsequent range of toxicant exposures associated with these additives and behaviors. Study outcomes include waterpipe puffing behaviors, exhaled carbon monoxide levels, nicotine uptake, spirometry, sensory perceptions, smoking appeal, and risk perception. Waterpipe tobacco smoking is often the first combustible tobacco product tried by adolescents and young adults, possibly due to the widespread availability of heavily sweetened waterpipe tobacco and the perception that waterpipe smoking is a safer alternative to cigarette smoking. However, waterpipe tobacco smoking is associated with lung disease, carbon monoxide poisoning, and precursor conditions for oral and other cancers in adolescents and young adults. There is currently little data available on how the primary additives (by weight) in waterpipe tobacco affect puffing behaviors, toxicant exposures, pulmonary function and appeal. This clinical trial uses established waterpipe tobacco smokers, four investigational tobacco products with precisely manipulated levels of humectants and natural sugars in a single-blind, crossover (repeated measures) study design to determine how waterpipe tobacco additives effect human puffing behavior, nicotine uptake, flavor perceptions, lung function, and biomarkers of exposure.

Currently there are no regulations governing the content of WP tobacco. Because mandated changes in tobacco content may lead to unintended consequences that ultimately result in public health declines, human use behaviors must be well understood prior to implementing regulatory product standards. The proposed study will include preparing and characterizing the content of 4 investigational tobacco products (ITPs) (Aim 1); characterizing the mainstream smoke toxicant emissions from machine smoking the 4 ITPs using a single, established puffing regimen (Aim 2); measuring human puffing behavior, general harm and specific health risk and flavor perceptions, lung function, and biomarkers of exposure in a group of established WP smokers smoking the 4 ITPs in the laboratory (Aim 3), and estimating toxicant exposure ranges using machine smoking and puffing regimens derived from the human laboratory testing (Aim 4).

The clinical trial (Aim 3) will focus on using a group of established adult and young adult WP smokers, a cross-over study design, CO and nicotine biomarkers, spirometry, cutting edge psychophysical measurement tools, and risk perception instruments to map the relationship between sensory experiences and preferences of sweetness and flavor to specific additive content in WP tobacco that affect these experiences, preferences, acute health effects, and toxicant exposures. Study subjects will participate in a series of 4 clinic sessions, each visit separated by at least a week, in which they smoke one of 4 tobacco preparations (single-blind) using a research grade waterpipe in a randomly assigned sequence in a smoking room with sufficiently controlled ventilation rate to keep ambient air CO levels below 25 ppm. Exhaled CO, whole blood samples and spirometry measures will be collected before and immediately after the smoking session. Taste perceptions, liking/disliking, and risk perceptions will be determined via questionnaires before, during, and after smoking.

Eligibility Criteria:
Inclusion Criteria:

* Sufficient understanding of consent form and study procedures
* Age 21-50 years old
* Experienced WP smokers defined as having smoked a WP at least 3 times per month in the last month
* Willing/able to abstain from nicotine product use for at least 12 hours prior to the laboratory visits
* Willing to attend four laboratory sessions at the same time of day lasting approximately 3 hours (h) each
* Read and speak English

Exclusion Criteria:

* Evident intoxication on any visit
* Exhaled breath CO \> 10 ppm
* Pregnancy (known or suspected), trying to become pregnant, breastfeeding, unwillingness to use contraception for the duration of the study
* Significant smoking-related disease (by history)
* Any of the following in the past 30 days (self-report):

  * Uncontrolled asthma or asthma that is worse than usual
  * Severe respiratory allergies, such as wheezing, coughing, shortness of breath when exposed to known allergens
  * Acute upper or lower respiratory illnesses like the flu, common cold, or pneumonia
  * Any other serious lung infection or disease, such as tuberculosis, cystic fibrosis, or lung cancer
  * Hospitalization for difficulty breathing
* Currently engaging in a WP tobacco smoking quit attempt