New research suggests that teens who use tobacco products are likely to use more than one product, including e-cigarettes, hookahs and pipes, and smokeless tobacco.

Researchers found that 14.7 percent of middle and high school students use one or more tobacco products. Among these users, 4.3 percent report using three or more tobacco products, and 2.7 percent of teens use cigarettes with an additional product.

"The prevalence of teens combining multiple tobacco products is alarming, especially since there may be potential additive harms associated with this practice," Youn Ok Lee, a research public health analyst at RTI International, said in a statement. "By using more than one tobacco product, teens may be increasing their risk of nicotine dependence."

For the study, researchers analyzed data from the 2012 National Youth Tobacco Survey, a nationally representative sample of U.S. middle and high school students, to estimate the use of cigarettes, e-cigarettes, cigars, smokeless tobacco, hookah and other tobacco products.

They found that 4.3 percent of youth report using three or more tobacco products in the past 30 days, compared to 2.8 percent who only used cigarettes. This percentage was also higher than the 2.4 percent of adults in the United States who used three or more products reported elsewhere.

The study findings are consistent with other reports suggesting that cigarette use is declining while use of other products, such as e-cigarettes and hookah, are gaining popularity among kids.

"Most individuals have their first experience with tobacco during their teen years," Lee said. "We found that the use of three or more tobacco products was associated with being male, using flavored tobacco products, nicotine dependence, tobacco marketing receptivity and whether the teen thought their peers used tobacco."

The study also showed that exclusive use of e-cigarettes among teens was twice as high as the usage of both e-cigarettes and conventional cigarettes.

Previous research by RTI found TV advertising for e-cigarettes has doubled for U.S. youth from 2010 to 2013 in the absence of the kind of federal regulations that apply to tobacco cigarettes. Another RTI study indicated that particles found in e-cigarette vapors may cause or worsen acute respiratory diseases, including asthma and bronchitis, among youth.

The findings are detailed in the journal Pediatrics.