In perhaps the strongest epidemiologic research of its kind to date, a case-control study of invasive cutaneous melanoma, involving more than 2,200 participants, found that any use of indoor tanning devices increased melanoma risk, but the risk was highest among those who engaged in indoor tanning most frequently. The findings were published online May 27 in Cancer Epidemiology Biomarkers and Prevention.

The results—from the Skin Health Study, conducted between 2004 and 2009 in Minnesota, a state with documented high indoor tanning use—are the first to show a clear dose-response relationship, with melanoma risk increasing by as much as 200 percent when indoor tanning usage exceeded 50 hours, 100 sessions, or 10 years. Over the last decade or so, the commercial tanning industry has introduced a number of newer technologies, and these were found to further increase the melanoma risk. Compared with people who have never used indoor tanning devices, those who used high-speed/high-intensity devices experienced 2.9 times the risk, and using high-pressure devices led to 4.4 times the risk. High-speed/high-intensity devices emit mostly UVA radiation plus a small percentage of UVB radiation; high-pressure devices emit UVA radiation almost exclusively.

This is the most solid, substantive study to date to specifically address the tanning device issue.

While it may not be possible to definitively distinguish between the effects of UVA versus UVB radiation employed in different devices, “the evidence indicates that all of these approaches do harm: there is no such thing as a safe device,” she emphasized. “And you don’t have to actually get a burn to incur the higher risk from indoor tanning, though we know that often happens.”

In 2009, the International Agency for Research on Cancer classified tanning devices as carcinogenic, emphasizing the risk to those exposed to indoor tanning before age 36. The current study did not confirm increased susceptibility for younger ages, but did suggest that those who start younger would likely go on to a greater lifetime exposure and, thus, face higher risk.

Indoor tanning has indeed become a social norm. As the study authors noted in the paper, a recent analysis of policies and laws on indoor tanning in 116 large U.S. cities found that “the average number of tanning salons exceeded the average number of Starbucks or McDonald’s.” And Dr. Lazovich cited data from the American Cancer Society stating that, nationally, 35 percent of 17-year-old girls report indoor tanning use. An FDA advisory panel recommended in March that the agency consider age restrictions or parental consent requirements for children under 18.