Kids who smoke hookah or use snus are more likely to move on to cigarettes, according to a new study.

“Hookah and snus could directly lead to cigarette smoking either by introducing teens to the practice of inhaling smoke, in the case of hookah, or creating an addiction to nicotine that can be better satisfied by cigarette smoking in the case of snus,” said lead author Samir Soneji of the Geisel School of Medicine at Dartmouth in Lebanon, New Hampshire.

“It's also possible that some teens are vulnerable to tobacco use, in general, and would have started smoking cigarettes even if they hadn't tried hookah and snus earlier,” he said.

The water-pipe device known as a hookah, with its series of tubes and mouthpieces, is almost always used to smoke tobacco and carries many of the dangers inherent in cigarette smoking. In one hour, hookah users may inhale as much smoke as they would from smoking 100 or more cigarettes (see Reuters story of Feb. 21, 2014 here: reut.rs/1jUByrE).

Snus, a smokeless product similar to dipping tobacco, was developed in Sweden in the 1700’s and introduced by U.S. tobacco companies in the mid-2000s when clean indoor air laws restricted cigarette smoking, the authors of the new study write.

Soneji and colleagues surveyed more than 2,500 young people, ages 15 to 23, during the 2010-2011 school year, asking if they had ever smoked cigarettes or used hookah or snus, and again two years later, focusing on frequency and intensity of cigarette smoking.

Of the more than 1,500 young people who completed both surveys, the vast majority - 1,048 - had never smoked cigarettes at the time of the first survey. Seventy-one of the never-smokers had used water pipes to smoke tobacco, and 20 had used snus.

Those kids were two to three times more likely to have begun smoking by the second survey than kids who had not used the alternative tobacco products, according to results in JAMA Pediatrics.

They were also more likely at the second survey to be current smokers, and they tended to smoke more often than those who had not tried hookah or snus two years earlier.

“The finding that use of both of these products at baseline predicted smoking at follow up is important, as it suggests that they may be a gateway to smoking,” said Dr. Pamela Ling, professor of medicine at UCSF School of Medicine in San Francisco.

Ling was not involved in the new research.

“We definitely can’t say that hookah use is necessary and sufficient for an adolescent to transition from a never smoker to a cigarette smoker,” Soneji said. “But I’m not certain that this precise causal relationship is needed for regulation. We ought to regulate other tobacco products to the level that they regulate cigarettes.”

The Food and Drug Administration does regulate smokeless tobacco products like snus, but it does not regulate hookah smoking, and the “shisha” used in the water pipes comes in many flavors, which may be attractive to young users, Soneji said.

Hookah bars and lounges may not fall under clean indoor air laws that prohibit cigarette smoking, and many do not serve alcohol and are open to 18- or 19-year-olds, Soneji noted.

“Federal and state laws prohibit the sale of hookah and snus to youth less than 18 years old,” he said. “Teen use of hookah may be growing, in part, because of a widespread misconception that hookah smoking is less harmful and less addicting than cigarette smoking.”

Snus may have a similar misguided appeal.

“In the U.S., snus is marketed by tobacco companies as less harmful than cigarettes,” Soneji said. “Snus is not smoked, although long-term use of snus increases the risk of oral cancer, preterm birth, and colorectal cancer.”

Regulating hookah and other alternative tobacco sources like cigarettes should be the next step, he said.

“A ban on flavored shisha may make hookah less appealing to youth,” Soneji said.

“Unlike other smokeless tobacco products, tobacco companies can distribute free samples of snus because the quantity of smokeless tobacco falls is less than 0.53 ounces of smokeless tobacco.,” he said. “Closing the loophole would prevent tobacco companies from providing free samples of snus to young adults.”