By Nathan Seppa, Science News
People with melanoma are more likely than those without it to have visited an indoor tanning salon, researchers find. The report, posted online May 27 in Cancer Epidemiology, Biomarkers and Prevention, is the latest in a host of studies linking indoor tanning to cancer (SN: 2/23/02, p. 126).
Many earlier studies, however, lacked information on the kind of ultraviolet rays people got while tanning indoors, the dose they received and the type of skin tone they had, says DeAnn Lazovich,a cancer epidemiologist at the University of Minnesota, in Minneapolis, who coauthored the new report.
Lazovich and her colleagues sent questionnaires to Minnesota adults with melanoma and collected 1,167 responses, which they matched with questionnaires returned by 1,101 randomly selected people who didn’t have melanoma. The researchers then made follow-up calls to record lifestyle habits of each group. They accounted for differences between the patients and the control group in hair color, light skin tone, eye color, frequency of moles, sun exposure, outdoor activities or jobs, sunscreen use, sunburns and any family history of melanoma.
People who tried indoor tanning had a 74 percent greater risk of developing melanoma than did those who avoided it, the researchers calculated.
The scientists also estimated that spending more than 50 hours on indoor tanning tripled a person’s melanoma risk. People who used indoor tanning for more than 6 years had roughly double the melanoma risk as the non-tanners. And salons that used ultraviolet-A radiation exclusively seemed to impart a slightly greater risk than those tanning with ultraviolet-B rays, the researchers found.
“This study was really well done,” says cancer epidemiologist Linda Titus-Ernshoff of Dartmouth Medical School in Hanover, N.H. “I think this suggests that everyone needs to stay away from tanning booths.”
Ultraviolet rays from the sun can cause common skin cancers such as basal cell and squamous cell carcinoma. But the connection between UV radiation and melanoma is less clear, even though some studies have associated melanoma risk to early-age sunburns.
In the new study, the researchers didn’t find any association between early use of tanning beds and melanoma. But Lazovich argues that early indoor tanning might nevertheless carry a danger, because cancer “takes a certain amount of time to develop” and UV damage from tanning might not have shown up in some people yet.
The U.S. Food and Drug Administration is currently looking into regulating tanning salons. In March, an FDA advisory panel suggested restricting use of tanning beds by light-skinned people and children or teens who don’t have parental consent.