Identifying correlations between the physico-chemical properties of waterpipe tobacco smoke and its impact on lung cell health, as a function of shisha flavor and smoking topography - PROJECT SUMMARY
Waterpipe use has risen to a global epidemic level and there remains a misperception among the public that
bubbling smoke through the hookah bowl liquid renders it safer than cigarette smoke. In fact, waterpipe
tobacco smoke (WTS) is more complex than cigarette smoke due to combustion products of the charcoal heat
source, volatilization and pyrolysis of the shisha’s tobacco and its flavored syrup and the effect that different
smoking behaviors (puffing, pausing) have on charcoal temperature and consequently smoke composition.
‘Fun’ shisha flavors have been shown to attract new users and the market includes an increasing catalog of
1000s of flavors, each with different, untested harm potential. Recent research in the field of electronic
cigarette aerosols showed that flavorings differentially contribute to radical generation and oxidative damage. It
follows, but has not been shown, that WTS generated from shisha flavored with the same compounds as those
found in e-liquids may cause similar oxidative damage. Our previous work demonstrates that smoke generated
from Apple Americano flavored shisha syrup, without tobacco, caused significant cell death and preliminary
data exposing cells to WTS from a panel of shisha flavors show differential cell health outcomes. It logically
follows that differences in the smoke are the cause of the variation in harm. Therefore, we propose parallel
investigations that a) characterize the physical and chemical properties that are unique to waterpipe tobacco
(shisha) flavor and/or flavor category and smoking topography, b) determine the harm this WTS causes in
alveolar cells exposed to whole smoke at the air-liquid interface, and c) define associations between physico-
chemical properties and measured cellular responses. Similarities and differences in alveolar cells’ levels of
cell death, and inflammation and oxidative stress responses will be correlated to the physico-chemical
properties of WTS, including particle size distributions and concentrations and chemical constituents, to
determine the relative contributions of flavor components and smoking topographies. The findings from this
study will provide a foundation that can inform public health policy and accelerate research developing
treatments and interventions that improve the health of individuals exposed to inhaled toxicants
