title: Comparison of tobacco-containing and tobacco-free waterpipe products: effects on human alveolar cells.
abstract: BACKGROUND
  In recent years, a class of products marketed as "tobacco-free" alternatives for the "health conscious user" has become widely available for waterpipe (hookah, narghile, or shisha) smoking. Their adoption may be in part driven by regulations banning tobacco smoking in public places and by an increasing awareness of the hazards of waterpipe tobacco smoking. Although these products are presented in advertising as a "healthier" choice, very little is known about their health effects.
  
  
  METHODS
  In this study, we compared the effects of smoke generated with tobacco-free and conventional tobacco-derived products on human alveolar cells. Smoke was generated with a smoking machine that precisely mimicked the puffing behavior of 15 experienced waterpipe smokers when they used conventional waterpipe tobacco products of their choice and flavor-matched tobacco-free products. Human alveolar epithelial cells (A549) were treated with particulate matter sampled from the smoke, and the effects on cell cycle, proliferation, and doubling time were measured during the subsequent 72hr.
  
  
  RESULTS
  We found that smoke from both types of waterpipe products markedly reduced cell proliferation, caused cell cycle arrest at G0/G1, and increased cell doubling time. There were no significant differences across product in any measure.
  
  
  CONCLUSIONS
  Tobacco-free and tobacco-based waterpipe products exert substantial and similar deleterious effects on human lung cells. This study adds to the nascent evidence base indicating that except for exposure to nicotine and its derivatives, use of tobacco-free waterpipe products does not present a reduced health risk relative to the use of conventional tobacco-based products.
authors.affiliation: Department of Mechanical Engineering, American University of Beirut, Beirut, Lebanon;
authors.forename: Alan
authors.initials: A
authors.lastname: Shihadeh
authors.forename: Thomas
authors.initials: T
authors.lastname: Eissenberg
authors.forename: Mayassa
authors.initials: M
authors.lastname: Rammah
authors.forename: Rola
authors.initials: R
authors.lastname: Salman
authors.forename: Ezzat
authors.initials: E
authors.lastname: Jaroudi
authors.forename: Marwan
authors.initials: M
authors.lastname: El-Sabban
mesh_terms: D000293:Adolescent; D000328:Adult; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects*; D006801:Humans; D008875:Middle Aged; D011650:Pulmonary Alveoli / Q000166:cytology; D012906:Smoke / Q000009:adverse effects*; D012907:Smoking / Q000009:adverse effects*; D062789:Tobacco Products / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D012906:Smoke