The rate of smoking has stopped falling in American children and health officials believe that the vaping of young people is responsible.

For decades, the percentage of high school students and college students who smoked cigarettes was declining steadily. According to new figures released Monday, it has been declining for three years.

There may be several reasons, but the most likely explosion is the recent explosion of vaping, said Brian King of the Centers for Disease Control and Prevention.

"We were making progress and we now have the introduction of a very popular product among young people that has completely erased these advances," King said.

The findings from the CDC come from a national survey conducted last spring with more than 20,000 high school and college students. He asked them if they had used tobacco products in the previous month. Some of the conclusions had already been published, including the vaping boom.

Experts attribute this increase to the growing popularity of new versions of electronic cigarettes, such as Juul Labs Inc. of San Francisco. The products look like USB keys, can be recharged via USB ports and can be used discreetly, even in school bathrooms and even in classrooms.

According to new data from the CDC, about 8% of high school students reported having recently smoked cigarettes in 2018 and about 2% of college students. These results were about the same as those observed in similar surveys in 2016 and 2017.

It was also found that about 2 out of 5 high school students who used a vapot or a tobacco product used more than one type and that the most common combination was that of electronic cigarettes and cigarettes. In addition, about 28% of high school electronic cigarette users said they were vaping 20 days or more the previous month, an increase of almost 40% over the year former.

Smoking, the leading cause of preventable disease in the country, is responsible for more than 480,000 deaths each year. The US Food and Drug Administration prohibits the sale of electronic cigarettes and tobacco products to those under 18 years of age.

Electronic cigarettes are generally considered better than cigarettes in adults already addicted to nicotine. However, for years, health officials have worried that e-cigarettes could lead children to smoke traditional cigarettes.

"I think writing is on the wall," with research suggesting more and more that electronic cigarettes are becoming a gateway to ordinary cigarettes, said Megan Roberts, a researcher at the University of Toronto. Ohio State University.

There are, however, differences of opinion among health researchers. Some had associated the electronic cigarette with an unusually large decline in teen smoking a few years ago. They argue that it is unclear to what extent the decline in smoking has stagnated or how much fault is to blame.

Smoking is still down in some states. And another major survey found that smoking continued to decline among 12th graders, but not among younger ones.

"We do not know yet what's going on and it's best not to draw any conclusions," said David Levy, a researcher at Georgetown University.

In a statement, a spokeswoman for Juul said that the company had taken steps to prevent children from using its products and that she was supporting the ban on the sale of electronic cigarettes to any person under 21 years old.

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