Ken Alltucker | USA TODAY

USA TODAY

A new study analyzing THC-containing vaping products provides more evidence linking a vitamin E derivative to an outbreak of lung illnesses that has sickened hundreds of people this year.

The Minnesota Department of Health report released Tuesday also might answer another pivotal question: Why are people getting injured now even though e-cigarettes have been available for a decade?

The state agency said 20 vaping products seized by law enforcement this year all tested positive for vitamin e acetate, an additive used in THC oil. However, testing showed none of 10 products recovered a year ago contained the substance.

Public health officials say the study provides a pivotal clue linking vitamin e acetate to this year's outbreak of 2,290 vaping-related lung injuries in 49 states, the District of Columbia, Puerto Rico and the U.S. Virgin Islands. Officials have confirmed 47 deaths.

"That may be an explanation why we are seeing these cases of severe lung injury now," said Ruth Lynfield, a Minnesota Department of Health epidemiologist and medical director.

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Earlier this month, the CDC discovered the vitamin E derivative in the lungs of patients hospitalized with vaping-related illnesses. The substance is sometimes used as an additive or thickening agent in vaping products containing THC, the marijuana compound that produces a “high."

Of 29 lung tissue samples from 10 states tested for the additive, all contained vitamin E acetate, the CDC said.

Anne Schuchat, the CDC's principal deputy director, said the discovery was a "breakthrough" and the first time officials found a potential toxin in samples from patients with lung injuries.

President Donald Trump last week said his administration would propose a minimum age of 21 for the purchase of e-cigarette products. The president's announcement comes as 5 million teens now report using e-cigarettes or vaping devices. Trump appeared to reverse course from September when his administration announced plans to remove all flavored vaping products from store shelves.

The Minnesota study focused on vaping products that contained THC, often secured through street dealers, Internet retailers or friends. The CDC recommends not using any products that contain THC and e-cigarettes or vaping devices obtained from such informal sources.

In addition to analyzing products seized by law enforcement, Minnesota officials recovered pods and devices from people with vaping-related lung injuries. Vitamin e acetate was detected in samples provided by 11 of 12 lung-injury patients. The person whose samples did not contain the additive did not provide all products he vaped, including Dank Vapes, Lynfield said.

Dank Vapes are THC-filled cartridges sold on the black market and often counterfeited.

Although the Minnesota study bolsters the link between vitamin e acetate and vaping-related illness, Lynfield cautioned the study was small, analyzed samples from one state and does not prove the substance causes lung illness.