Tanning bed users have nearly double the DNA damage to skin cells, new study finds

15 Dec 2025, 14:19 by Lisa Schencker · The Seattle Times

A new study out of Northwestern Medicine is highlighting the risks of tanning beds, and showing how they can lead to skin cancer.

Not only is the use of tanning beds associated with nearly triple the risk of developing melanoma, but heavy users of tanning beds also had more damage to the DNA of their skin cells, according to the study published Friday in the peer-reviewed journal Science Advances.

Dr. Pedram Gerami, a professor of skin cancer research at Northwestern University Feinberg School of Medicine, decided to look into the issue of tanning beds and melanoma after noticing that an unusually large number of his patients were women younger than 50 who had had melanoma multiple times.

Melanoma is the deadliest form of skin cancer, though it is highly curable if caught early.

“You’d see the common thread linking all these women was a history of tanning bed exposure,” said Gerami, who is also director of the Pigmented Lesion and Melanoma Clinic at Northwestern Medicine.

Gerami teamed up with researchers from the University of California, San Francisco to examine the medical records of nearly 3,000 patients who used tanning beds at least 10 times in their lives and nearly 3,000 patients who never used tanning beds. They found a 2.85-fold increase in melanoma risk for patients who used tanning beds compared with those who did not, after adjusting for age, sex and sunburn and family history, according to the study.

The researchers then sought to find out how much DNA damage may be caused by tanning beds by examining skin samples from 27 patients. Eleven of those patients reported that they had used tanning beds at least 50 times in their lives, nine patients were at high risk for skin cancer but not from frequent tanning bed usage, and six of the skin samples were taken from cadavers, to augment the control group.

The researchers used relatively new technology to perform single-cell DNA sequencing on melanocytes, which are the skin cells that produce pigment.

They found that skin cells from patients who used tanning beds had nearly twice as many mutations as skin cells from patients who didn’t use tanning beds, and they were more likely to have melanoma-linked mutations.

“In the skin that looks normal in a tanning bed patient, you can find that their skin cells will have the DNA mutations that we know predispose (a person) to melanoma,” Gerami said.

“(For) a lot of these patients, the majority of their tanning bed exposure occurred in their youth, maybe even when they were minors,” he said. “Now, as adults, often early adults or mid-adult life, is when they’re finally dealing with the consequences of those exposures.”

That’s what happened to Heidi Tarr, a patient of Gerami’s who agreed to be part of the study.

In high school and college, Tarr said she used tanning beds multiple times a week. At the time, she thought it was safer than potentially burning in the sun.

“My friends and I, in high school and through college we used tanning beds regularly,” Tarr said. “It was part of feeling beautiful, I guess, having a tan.”

In 2011, she noticed that a mole on her back had changed in color and size. She underwent a biopsy and learned that she had melanoma. Luckily, she caught it early, underwent surgery and has been cancer-free ever since. But she must continue to get her skin checked every six months for the rest of her life, she said.

“You think you’re getting a tan but what you don’t see is you’re damaging your skin cells, and that damage can lead to melanoma,” Tarr said.

Tarr didn’t hesitate to participate in Gerami’s research. “I wanted to help the medical community and his research, but I really wanted to help other patients,” she said. “I just wanted to do anything I could to give back.”

Pedrami would like to see more states limit use of tanning beds among minors and stronger warnings of the risks of tanning beds. A number of states (including Washington state) prohibit people younger than 18 from using tanning beds.

The U.S. Food and Drug Administration already requires tanning beds to have labels informing people of the risks of using them and urging against their use for people younger than 18.

Industry group the American Suntanning Association has criticized past research on tanning beds and skin cancer, saying on its website that many of the studies have relied on self-reported survey data and fail to “isolate independent variables, such as assessing whether subjects sunburned repeatedly or exposed themselves responsibly.”

“We acknowledge that there are risks associated with overexposure to the sun and sunbeds, including skin cancer,” the association says on its website. “But it’s important that we keep these risks in perspective while determining public health policy decisions. Discussion of the nuance and critical confounding factors in the research isn’t happening yet.”

Meanwhile, the American Academy of Dermatology association opposes indoor tanning and would like to see a ban on the production and sale of indoor tanning equipment for nonmedical purposes.

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