DULUTH — Mint rules among U.S. high school students who use the popular Juul e-cigarettes, says a study released Tuesday, Nov. 5, by the Journal of the American Medical Association.

That puts in doubt the effectiveness of Juul’s recent announcement that it would stop selling its non-tobacco, non-menthol flavors, pending review by the Food and Drug Administration. The list of flavors to be suspended didn’t include mint.

“The current findings raise uncertainty whether regulations or sales suspensions that exempt mint flavors are optimal strategies for reducing youth e-cigarette use,” wrote Adam M. Leventhal of the University of South California Institute for Addiction Science and five co-authors of the “research letter” published online by the journal.

The researchers used data from what’s known as the Monitoring the Future study, which seeks responses from students in eighth, 10th and 12th grades. It took place between Feb. 13 and June 3 of this year.

Mint was easily the most popular choice for both 12th graders and 10th graders, followed by mango and fruit. Classic tobacco, creme, cucumber, menthol and Virginia tobacco lagged far behind.

Among 8th graders, mango edged mint for the top choice.

That’s no surprise to Taylour Blakeman, a health specialist at the American Lung Association in Duluth. “I’ve heard a lot of mango, mint,” she said. “Mango and mint are at the top.”

John Muenich, Hermantown High School principal, said mango and anything citrus-based seem to be most commonly seen at the school.

Mango was one of the flavors Juul said it would suspend, along with creme, cucumber and fruit.

But the damage already has been done, Muenich said.

“They already have a customer base of teenagers who are very much addicted to nicotine already,” he said.

Last year, the Duluth City Council passed an ordinance banning the sale of all flavored tobacco products, including menthol, except at adults-only smoke shops.

At the same time as it published the research on flavors, the American Medical Association released research indicating that vaping continues to be popular among U.S. youth. More than one out of four high school students and one out of 10 middle school students said they had used e-cigarettes at least once in the previous 30 days, according to the study led by Karen A. Cullen of the Center for Tobacco Products, U.S. Food and Drug Administration. The survey of more than 10,000 high school students and close to 9,000 middle school students was conducted between Feb. 15 and May 24 of this year.

If the results hold true for the population as a whole, it would mean about 4.1 million high school students and 1.2 million middle school students vape, the study’s authors wrote.

The national study is similar to the data reported recently in the 2019 Minnesota Student Survey in which one of four high school juniors said they had vaped at least once in the previous 30 days. But the percentages were higher in St. Louis County, where 35% of 11th grade boys and 31% of girls self-reported vaping during the previous 30 days.