Millions of Americans use e-cigarettes, the majority of them younger adults and teenagers. The battery-powered devices, also known as vapes, have often been promoted to younger demographics as a lower-risk alternative to smoking regular cigarettes.
Now a new analysis of global research – “one of the most detailed attempts“ to determine this impact so far,” according to Australia’s University of New South Wales – says that e-cigarettes are likely to cause lung and mouth cancer.
The cancers are expected to lead to 138,140 deaths in the U.S. this year.
“Considering all the findings – from clinical monitoring, animal studies and mechanistic data – e-cigarettes are likely to cause lung cancer and oral cancer,” Adjunct Professor Bernard Stewart, a cancer researcher at the university, said in a statement.
“To our knowledge, this review is the most definitive determination that those who vape are at increased risk of cancer compared to those who don’t,” he noted.
The review consulted clinical studies, animal experts and lab research examining the chemicals produced by e-cigarettes and their effects, the university said.
The studies the university’s researchers looked at showed vaping was linked to inflamed tissue and oxidative stress, which are both signs of damaged DNA. There were also some experiments in mice that showed vaping caused lung tumors and lab studies that found “cellular damage and disrupted biological pathways linked to cancer.”
Weed killer, preservative and food additive
The researchers identified “numerous” cancer-causing chemicals in the e-cigarette aerosols the devices produce to inhale, including chemicals, metals and volatile organic chemicals.
Aerosols can contain cancer-causing chemicals, volatile organic compounds and heavy metals like nickel, tin and lead, tiny particles that can be inhaled deep into the lungs, the U.S. Centers for Disease Control and Prevention says.
The volatile organic compounds include the carcinogen and preservative formaldehyde, the food additive diacetyl and the weed killer acrolein, according to Johns Hopkins Medicine. Acrolein and diacetyl are tied to lung disease.
“The evidence was remarkably consistent across fields,” UNSW Associate Professor Freddy Sitas added. “It dictated an unequivocal finding now, though human studies that estimate the risk will take decades to accumulate.”
Still, the researchers say they will only be able to determine what the precise risk is when longer-term studies on humans are available.
‘The inflammation is happening’
Other researchers had previously said e-cigarettes had not been around long enough to definitively say they caused cancer and that health consequences were just starting to be understood.
“We do know that smoking tobacco forces tiny particles to be deposited deep in the bronchial tree and can lead to the development of cancer,” Johns Hopkins Medicine lung cancer surgeon Stephen Broderick previously explained. “The same may be true for vaping.”
Biologically, “damage is happening” even if you cannot see negative effects right away, Dr. Panagis Galiatsatos, a pulmonary and critical care physician at Johns Hopkins Medicine, told the American Lung Association.
“The inflammation is happening. And the concern is, we’re creating the conditions that will lead to those diseases later,” he said.
There are still 480,000 deaths from smoking cigarettes each year in the U.S., with many tied to cancer, according to the American Cancer Society. Projections released by the society earlier this year said 124,990 people would die from lung cancer.
Although cigarette use has decreased among U.S. adults, e-cigarette use has increased. Newly released CDC data found that seven percent of Americans used e-cigarettes in 2024.
The CDC says that while e-cigarettes don’t have all of the contaminants in tobacco smoke, they are still unsafe.
“E-cigarette aerosol generally contains fewer harmful chemicals than the deadly mix of 7,000 chemicals in smoke from cigarettes. However, this does not make e-cigarettes safe,” the CDC says.
