WEDNESDAY, May 14 (HealthDay News) -- The increasing use of waterpipes, or hookahs, by U.S. college students could become a serious public health problem, according to a Virginia Commonwealth University study.

In hookahs, tobacco is heated by charcoal, and the smoke is cooled by passing through a water-filled chamber before it reaches the smoker. Some people believe hookahs are less dangerous and addictive than cigarettes, but that's not true.

About 43 percent of 744 students, aged 18 to 21, who completed an Internet survey, said they'd smoked tobacco using a hookah in the past year. Twenty percent had used a hookah in the past month. Users were more likely than non-users to think that hookahs were less harmful than cigarettes.

The study was published in the May issue of the Journal of Adolescent Health.

"The data we report, along with data from other schools, show that waterpipe tobacco smoking is common on college campuses across the country. Thus, prevention messages, especially those that communicate the potential risks of waterpipe tobacco smoking, should focus on college campuses," principal investigator Thomas Eissenberg, an associate professor in VCU's department of psychology, said in a prepared statement.

He said waterpipe and cigarette smoke contain some of the same toxins as well as addiction-causing nicotine. Exposure to toxins may be greater among hookah users due to longer periods of use and the fact that hookah users take more and larger puffs of smoke than cigarette smokers.

"These results should serve as an alarm bell to anyone interested in public health in the United States. Preventing tobacco-caused death and disease means remaining alert to new forms of tobacco smoking and then understanding the health risks of these new forms and communicating these risks to public health workers, policy makers, and to smokers themselves," Eissenberg said.

In future studies, he and his team would like to assess the prevalence of hookah tobacco use in the U.S. general population and examine its potential health risks and dependence-producing effects.