New research from the Centers of Disease Control and Prevention reveals some good and bad news: The prevalence of cigarette use among high school students has decreased in the past four years, but there has been a substantial increase in e-cigarettes use, more commonly known as vaping, among this age group.

Tobacco use is the leading cause of preventable disease and death in the U.S., with more than 16 million U.S. adults living with a smoking-related disease, and more than 480,000 people dying each year from the habit. Although e-cigarettes, battery-operated tobacco products that emit vapors, are thought to be a safer alternative to conventional cigarettes, its risks and benefits are still not fully understood. Since the use of tobacco products mostly begin during youth and young adulthood, researchers at the CDC aimed to understand the prevalence and trends of current tobacco products.

The study, which was done in collaboration with the Food and Drug Administration (FDA), analyzed data from the 2011-2015 National Youth Tobacco Surveys. Researchers found regular cigarette use dropped from 15. 3 percent to 9.3 percent during this time period; meanwhile, the use of e-cigarettes jumped from 1.5 to 16 percent among the same group.

In 2015, more than one in four high school students reported using a tobacco product at least once within the past 30 days, and e-cigarettes were the most commonly used product.

“We’re very concerned that one in four high school students use tobacco, and that almost half of those use more than one product,” Dr. Corinne Graffunder, director of CDC’s office on smoking and health, said in a statement.

What’s more, electronic cigarettes seem to have become popular among tweens. The report found that in 2015, the electronic devices were also the most commonly used tobacco product among middle school students, rising from 0.6 to 5.3 percent.

With researchers still working out how exactly e-cigarette use impacts health, the trend is cause for concern. Some research may deem the electronic devices as a safe alternative to regular cigarettes, but other studies have shown it hurts the immune system worse than old-fashioned cigarettes and can even serve as a gateway to its conventional counterparts. E-cigs also still contain nicotine, a highly addictive drug.

“E-cigarettes are now the most commonly used tobacco product among youth, and use continues to climb,” said CDC Director Dr. Tom Frieden. “No form of youth tobacco use is safe. Nicotine is an addictive drug and use during adolescence may cause lasting harm to brain development.”

In addition to e-cigs and cigarettes, middle and high school students are also using other tobacco products, including cigars, hookah, and bidis. Overall, an estimated 4.7 million high school and middle school students reported current use of any tobacco product. While researchers have observed significant decreased in the use of conventional cigarette products such as cigarettes and cigars, the significant increase in e-cigarettes use among this group resulted in no decline in tobacco use overall.

In an effort to reduce youth tobacco use and initiation, the FDA is currently working on plans to bring additional tobacco products such as e-cigarettes and hookahs under their authority. This way they can regulate the manufacturing, distribution, and marketing of tobacco products, while using “proven population-based strategies,” such as increasing prices of tobacco products, implementing and enforcing comprehensive smoke-free laws, to reduce tobacco product use in this age group.

Source: Singh T, Arrazola R, Corey C, et al. Tobacco Use Among Middle and High School Students — United States, 2011–2015. Morbidity and Mortality Weekly Report. 2016.