Tanning bed use associated with 74% increased risk for melanoma

UVA radiation increased risk more than 400%.

Results of a study published online Thursday showed that those who use tanning beds are at high risk for developing melanoma and the risk increases in proportion with use.

These new findings remove some previous limitations and provide “strong support” for the International Agency for Research on Cancer’s recent declaration that tanning devices are carcinogenic, said DeAnn Lazovich, PhD, associate professor of epidemiology and community health in the School of Public Health and Masonic Cancer Center at the University of Minnesota.

The full study was published in Cancer Epidemiology, Biomarkers & Prevention.

“People who used indoor tanning devices were at about 74% increased risk of developing melanoma compared with persons who had never tanned indoors,” she said during a press conference. “We found that the risk of melanoma increased with the amount of tanning, and this was the case whether we assessed by hours, years of use or total numbers of sessions. For those in the highest categories of use — defined as 50 or more hours, more than 100 sessions or 10 or more years — their risk for melanoma was 2.5 to three times higher than never users.”

Researchers observed this dose-response regardless of tumor location, Lazovich said.

Skin and Health Study

Researchers recruited participants from the Minnesota Cancer Surveillance System, a population-based, statewide cancer registry. Patients who had been diagnosed with invasive cutaneous melanoma from July 2004 to December 2007, were aged 25 to 59 years and had a state driver's license or state identification card were eligible. Controls were randomly selected from the Minnesota state driver's license list and frequency-matched to patients in a 1:1 ratio based on age and gender.

Participants completed a self-administered questionnaire and took part in a one-hour phone interview. Among those contacted by researchers, 1,167 patients and 1,101 healthy controls participated in the study from December 2004 to March 2009.

Almost 63% of patients and 51.1% of controls reported using indoor tanning. The multivariate-adjusted OR for the likelihood of melanoma in relation to having ever tanned indoors was 1.74 (95% CI, 1.42-2.14). Lazovich added that increased risk was strongly correlated with frequency of use.

After adjusting for age at initiation among indoor tanners, the risk for melanoma was highest among those who had tanned for 10 or more years compared with those who had only been tanning for one year (adjusted OR=1.77; 95% CI, 1.19-2.63).

Researchers added that patients were more likely to have reported painful burns while tanning indoors (OR=2.28; 95% CI, 1.71-3.04), experienced a greater number of burns while using a tanning device or experienced painful sunburns at a time when they thought they were protected from the sun by indoor tanning (OR=2.00; 95% CI, 1.48-2.70).

Canada and the United Kingdom have taken steps to outlaw indoor tanning for those younger than 18 years and the FDA has considered a similar ban. However, researchers found the risk for melanoma was elevated no matter when users began tanning indoors. The risk was highest for those who began tanning before age 18 (OR=2.18; 95% CI, 1.62-2.94), but those who began tanning from 18 to 24, 24 to 34, and 35 and older were all at increased risk.

Additionally, researchers found that high-speed or high-pressure devices increased the risk for melanoma from 2.86 times to 4.44 times the risk for those who had never used an indoor tanning device. Melanoma risk was especially elevated among users of UVB-enhanced (OR=2.86; 95% CI, 2.03-4.03) and primarily UVA-emitting devices (OR=4.44; 95% CI, 2.45-8.02).

Mounting data

Melanoma incidence has been growing in the United States since the 1970s. The American Cancer Society estimated there were 68,720 incidence of melanoma diagnosed last year and 8,650 deaths, although the death rate has been dropping for those aged younger than 50 years.

“There’s no question that the data have been mounting and that we do know that tanning beds are part of the problem,” said Allan Halpern, MD, chief of the dermatology service at Memorial Sloan-Kettering Cancer Center. “Tanning bed use is associated with increased melanoma risk. These data are a very important addition to that body of knowledge.”

The International Smart Tan Network issued a release a day earlier attacking the findings by saying researchers “reverse-engineered” the results “to bolster its own pre-existing anti-indoor tanning crusade, failing to properly cite the significance of conflicting data within its own paper, downplaying confounding data that opposed its conclusions and failing to disclose the conflict-of-interest of its own anti-tanning advocacy efforts.”

“Let me make clear: I am not an advocate,” Lazovich said in response. “I am a cancer researcher. I have been conducting research on this topic since about 2000 and all of our research has been peer-reviewed by the National Institutes of Health, funded by the National Cancer Institute and reviewed locally by our university institutional review board.” – by Jason Harris

Lazovich D. Cancer Epidemiol Biomarkers Prev. 2010;doi:10.1158/1055-9965.EPI-09-1249.