New research is suggesting that hookah smoking can impair the endothelial function of blood vessels, which is a key indicator of cardiovascular health.
More and more people are giving up smoking, and they are sensible to do so.
Cigarette smoking is "the leading preventable cause of death in the United States," according to the Centers for Disease Control and Prevention (CDC), with cigarettes causing over 480,000 yearly deaths.
However, is hookah smoking truly safe? Several recent studies suggest that the answer is "no." For example, a study that Medical News Today covered in 2016 found that a single session of hookah smoking delivers 10 times the amount of carbon monoxide present in a regular cigarette.
Another more recent study found that hookah, also known as shisha, smoking can stiffen the arteries to a degree comparable with that which normal cigarettes can achieve.
Arterial stiffness is a predictor for stroke, and so is the enlargement of the aorta, which is another effect that hookah smoking was found to have.
Now, new research presented at the American Heart Association's (AHA) Scientific Sessions 2018 — which took place in Chicago, IL — adds to the evidence that suggests hookah smoking may indeed harm cardiovascular health.
Mary Rezk-Hanna, Ph.D., an assistant professor at the University of California, Los Angeles School of Nursing, is the lead author of the study.
Studying the effects of hookah smoking
Rezk-Hanna and colleagues examined 30 young, healthy adults before and after they took part in a session of hookah smoking. The participants were 26 years old, on average.
The team examined the participants' blood levels of nicotine before and after the smoking session and measured their exhaled carbon monoxide levels and a marker of artery function called flow-mediated dilation of blood vessels.
The latter measure describes the dilation, or widening, of blood vessels when blood flow increases. Flow-mediated dilation is a measure of the endothelial function of arteries, and many consider endothelial dysfunction to be "the initial phase of the atherosclerotic process."
In this study, the researchers compared the results of these measures with the effects of one normal cigarette in age-matched people who smoke regular cigarettes.
Also, Rezk-Hanna and team took the same measurements before and after hookah smokers were asked to use an electronic device to vape a mixture of carbon monoxide gas that mimicked the effects that people normally get from charcoal-heated hookah smoking.
How hookah smoking may harm the arteries
The researchers revealed that exhaled carbon monoxide levels were nine to 10 times higher in charcoal-heated hookah smoking than in electronically heated hookah or regular cigarette smoking. Nicotine levels, however, were equally high across all smoking sessions.
Also, the study discovered that flow-mediated dilation was higher after charcoal-heated hookah smoking, while electronically heated hookah or traditional cigarette smoking lowered flow-mediated dilation. A lower flow-mediated dilation indicates endothelial dysfunction.
The researchers explain that the main difference between charcoal-heated and electrically heated hookah is that charcoal briquettes produce high levels of carbon monoxide.
This chemical, in turn, dilates blood vessels, which, the authors speculate, might mask the damaging effects of charcoal-heated hookah smoking on endothelial function.
So, hookah smoking may harm blood vessel function in the same way as cigarette smoking.
"Hookah is the only form of tobacco product that uses burning charcoal briquettes to heat the flavored tobacco in the water pipe. So, in addition to toxic substances from tobacco and nicotine, hookah smoke exposes users to charcoal combustion products, including large amounts of carbon monoxide."
Mary Rezk-Hanna, Ph.D.