Many teens who use e-cigarettes are often unaware of the amount of nicotine they ingest, a study published in the journal Pediatrics suggests.
The study, published online Monday, surveyed 500 teens between the ages of 12 and 21, asking about their use of tobacco, e-cigarettes and marijuana. Of that group, 265 offered a urine sample to track cotinine, a product formed in the body after nicotine use.
The study found 40 percent of participants who reported using products free of nicotine had levels of cotinine higher than the cut-off indicating nicotine use.
Also, participants using higher nicotine content devices like Juul had significantly higher levels of cotinine in their system, "comparable or even higher to what you see with kids who smoke cigarettes," said Dr. Rachel Boykan, lead author of the study from the Department of Pediatrics at the Renaissance School of Medicine at Stony Brook University.
"As we are starting to see really an increase in usage of e-cigarettes, we really hadn’t defined very well the amount of nicotine kids were getting from them," Boykan told USA TODAY.
Boykan said there are several factors contributing to why teens and even adults might be unaware of nicotine levels in e-cigarettes, including marketing that says they're safer than cigarettes.
"We’re talking about kids getting addicted to nicotine and using these things because they perceive them as being safer than cigarettes, but these are kids that would not have been smoking in the first place," said Boykan.
The Food and Drug Administration released new guidelines last month regulating the sale of flavored e-cigarettes, part of a larger effort to reduce the number of kids who use the products.
The FDA said 3.6 million middle and high school students considered themselves current e-cigarette users in 2018, more than double the previous year.
Meanwhile, businesses and governments have started weighing broader restrictions to access to e-cigarettes and other tobacco products. In March, officials in San Francisco introduced legislation to ban e-cigarettes until the federal government approves regulations.
Last week, Senate Majority Leader Mitch McConnell said he would introduce a bill raising the minimum age for buying tobacco products from 18 to 21. Then, on Tuesday, pharmacy chain Walgreens said it would implement a policy starting in September to limit tobacco product sales to customers age 21 and older.
Follow Brett Molina on Twitter: @brettmolina23.
This article originally appeared on USA TODAY: Teens are vaping nicotine and they don’t even realize it, study says