Abstract 20449: Differential Effects of Hookah and Cigarette Smoking on Endothelial Function: Role of Charcoal Combustion
Introduction: Hookah (water pipe) smoking is a new global epidemic of tobacco abuse affecting youth. While hookah smokers endorse social media claims that hookah is healthier than cigarettes, there is paltry scientific evidence to refute this claim. While cigarette smoking unequivocally impairs vascular endothelial function, the effect of hookah is unknown.
Hypothesis: Because hookah tobacco traditionally is heated with burning charcoal, hookah delivers tobacco-specific “tar” and nicotine plus charcoal combustion products. These include carbon monoxide and proatherogenic carbon-rich nanoparticles that can impair endothelial function. Thus, my colleagues and I hypothesized that hookah acutely impairs endothelial function to a greater extent than cigarettes.
Methods and Results: In 23 healthy young adults who smoke hookah but not cigarettes (age 25±1 years, mean±SE; BMI 23.9±0.5 kg-m2), we measured brachial artery flow-mediated dilation (FMD) before and after a 30-minute session of ad lib hookah smoking using the traditional charcoal-heated water pipe. Surprisingly, FMD did not decrease but increased sharply by +50±9% (6.9±0.5 to 9.7±0.6%, pre- vs. post- hookah smoking, p<0.001). In contrast, in 8 cigarette smokers (matched on age, gender, race, BMI), after smoking one cigarette, as expected FMD decreased by -36±4% (6.0±1.0 to 3.9±0.7%, p<0.001). To determine if charcoal combustion products explain directionally opposite effects of hookah vs. cigarettes on FMD, in 6 hookah subjects we replaced charcoal briquettes in the hookah with an electronic heat source (“e-coal”). While e-coal is marketed as healthier than charcoal, after smoking e-coal-heated hookah, FMD decreased by -32±7% (6.5±1.4 to 4.6±1.1%, p=0.009), which is indistinguishable from the decrease with cigarettes.
Conclusion: These novel data: (1) show that hookah smoking constitutes a potent acute stimulus to augment (not impair) endothelial function in young adults; and (2) implicate a pivotal mechanistic role for “toxic” charcoal combustion products in this counterintuitive enhancement of vasodilation. To inform evidence-based policy on hookah regulation, further plans are to determine how these differential acute effects influence long-term atherosclerotic risk.
Author Disclosures: M. Rezk-Hanna: None. O. Mason: None. R. Rosenberry: None. D. Tashkin: None. N.L. Benowitz: None. L.V. Doering: None. W. Robbins: None. L. Sarna: None. R. Elashoff: None. R. Victor: None.
- © 2016 by American Heart Association, Inc.