• Researchers examined thousands of medical records to compare melanoma rates in people who used tanning beds and those who did not, then performed genomic analysis on 182 skin biopsies from both groups to track mutation patterns.
• People who used tanning beds showed nearly twice as many DNA mutations as individuals in the control group.
• These mutations were found not only on commonly exposed skin, but also in body areas that rarely see sunlight, revealing how far tanning bed damage can spread.

Indoor tanning, melanoma risk and DNA damage

Using tanning beds is linked to nearly a threefold increase in the risk of melanoma, and for the first time, researchers have shown how these devices create melanoma-related DNA damage across almost the entire surface of the skin, according to a new study led by Northwestern Medicine and the University of California, San Francisco.

Melanoma is the most lethal form of skin cancer and is responsible for about 11,000 deaths in the U.S. each year. For years, health experts have warned about the dangers of indoor tanning, yet the exact biological pathway connecting tanning beds to cancer had not been fully mapped.The indoor tanning industry, which has been experiencing a resurgence in popularity, has pointed to that gap in knowledge to claim that tanning beds are no more perilous than natural sunlight.

the new research, the authors say, “irrefutably” counters those arguments by demonstrating that tanning beds, at the molecular level, change skin cells in ways that go far beyond the impact of everyday sun exposure.

“Even in normal skin from indoor tanning patients, areas where there are no moles, we found DNA changes that are precursor mutations that predispose to melanoma,” said study first author Dr. Pedram Gerami, professor of skin cancer research at Northwestern University Feinberg School of Medicine. “That has never been shown before.”

The findings were published dec. 12 in the journal Science Advances. Science Advances

Clinical mystery in younger melanoma patients

Gerami, who also directs the melanoma program in dermatology at Northwestern, has treated people with melanoma for two decades. During that time,he began to notice a striking pattern: an unusually high number of women under age 50 who had experienced multiple melanomas and reported using tanning beds. He suspected that frequent indoor tanning was the shared factor tying these cases together.

To investigate, gerami and his team designed the epidemiologic portion of the study.They analyzed medical records for about 3,000 people with a history of tanning bed use and compared them with roughly 3,000 age-matched individuals who had never used indoor tanning devices.

In this comparison, melanoma was diagnosed in 5.1% of people who used tanning beds, versus 2.1% of those who did not.Even after the researchers accounted for age, sex, history of sunburn, and family history of melanoma, indoor tanning was still associated with a 2.85-fold increase in melanoma risk.