By: Rachael Rettner
Published: 02/20/2015 10:13 AM EST on LiveScience
There's a common belief that smoking from a hookah is less harmful than smoking tobacco in other ways because the hookah's water-filled pipe filters out toxic chemicals. But a new study officially debunks this myth, showing that a large fraction of heavy metals in tobacco are still present in hookah smoke.
In the study, researchers at German Jordanian University in Jordan analyzed four tobacco samples purchased at local markets that represented the most popular brands and flavors in the country. They looked at the amount of heavy metals in the tobacco itself, as well as the amount of heavy metals that made their way into hookah smoke. (In a hookah, tobacco smoke first travels into a water container, from where it bubbles up before being inhaled through a hose.)
They found that a number of heavy metals were present in the tobacco samples as well as in hookah smoke, including copper, iron, chromium, lead and uranium.
The water filtered out about 3 percent of the heavy metals present in tobacco, while about 57 percent of the heavy metals made their way into hookah smoke. (The rest wound up in the tobacco ash.) [4 Myths About Hookah Health]
The small percentage of heavy metals filtered out by the hookah water "would not protect the user against exposure to the majority of the potentially toxic metals," the researchers wrote in the Feb. 19 issue of the journal BMC Public Health. The findings provide "further evidence in support of disproving the belief that the use of a water pipe would protect from the harmful effects of tobacco smoking," they said.
Previous studies have found that hookah use among U.S. teens and young adults is on the rise, with about 15 to 17 percent of high school seniors, and up to 40 percent of college students, reporting that they had used a hookah in the past year, according to the Centers for Disease Control and Prevention.
Many people mistakenly believe that hookahs are safer than cigarettes, but studies have found a link between hookah use and an increased risk of lung cancer, oral cancer, respiratory problems and other conditions, the CDC says. A study published in December found that hookah users are also exposed to the chemical benzene. The chemical can be found in emissions from burning charcoal in a hookah, and it has been linked with leukemia.
In the new study, the researchers noted that, because the amount of heavy metals in tobacco can differ depending on where the plant is grown, the results might be different if other tobacco products were used. In addition, different types of pipes, such as pipes that use liquids other than water, may affect a person's exposure to heavy metals, they said.