The study covered a total of approximately 2,300 subjects, of which about half were controls. The study evaluated age of first exposure, the evolution of bed tanning technology in time, the types of tanning beds used, the frequency and duration of exposure, and attempted to correct for bias in subject selection. Some of the study's goals were to improve upon the limitations of previous studies on indoor tanning, which had not been able to investigate in depth frequency and duration of exposure, or age of first exposure, and had not been able to control for other factors such as exposure to sun.
There was no link detected between risk and age of first exposure (when subjects had started using tanning beds), and there was no significant difference for exposure before or after 1980, the approximate date when tanning bed technology underwent significant changes. The use of tanning beds of any kind and in any duration or frequency was associated with a 1.72 times increase in risk of melanoma, while use over a 10 year period was associated with a 2.45 times increased risk, use of high speed beds (a combination of UVA and UVB) was accompanied with a 2.86 times increased risk, and use of high pressure beds (primarily UVA) was accompanied with a shocking 4.44 times increased risk. There was a strong correlation between more tanning bed use and more risk, with frequency of over 100 sessions associated with 2.72 times increased risk, and a total usage over 50 hours associated with 3.18 times increased risk.
Case subjects (i.e. with melanoma) were more likely than control subjects (i.e. without melanoma) to have fair or very fair skin, many moles, red or blond hair, and freckles. They also reported more burns in tanning beds, and more burns from sun exposure after they had tanned indoors. On the other hand, the study did not appear to show influence from family history of melanoma, or from outdoor exposure from the sun.
"It had been previously thought that those tanning with UVB, rather than UVA, radiation would be at increased risk for melanoma. Our study shows that there is no such thing as a safe device," said Dr. DeAnn Lazovich, principal investigator of the study, an associate professor of epidemiology at the University of Minnesota's School of Public Health and co-leader of the Prevention and Etiology Research Program at the University's Masonic Cancer Center. "Risk rises with frequency of use, regardless of age, gender, or device," said Lazovich. She explained that previous studies had not been able to strongly link indoor tanning with increase risk of melanoma: "Most reports were not able to adjust for sun exposure, confirm a dose-response, or examine specific tanning devices... Our population-based, case-control study was conducted to address these limitations."
Take-aways from Lazovich's discussion of the study:
- Indoor tanning significantly increases risk for melanoma
- Frequency of use and total exposure duration are directly linked to increased risk of melanoma
- Age of first exposure is not a significant issue in increasing risk (except for likelihood of longer lifetime exposure)
- Both UVA and UVB appear to contribute to increased risk
- All types tanning beds increase risk - there is no safe platform
The Indoor Tanning Association and the International Smart Tan Network, two trade organizations representing tanning professionals (a $5B industry), oppose the conclusions of the study. Indoor Tanning Association's spokesman John Overstreet says: "When reputable researchers are coming to vastly different conclusions, it's clear that a lot more research is needed... The science on both sides of the question needs to be weighed before consideration is given to any sweeping policy changes." Smart Tan's news release also disagrees: "In suggesting that tanners double their risk of melanoma, the authors mention only relative risk figures in the paper, ignoring that more telling figure that the absolute risk of melanoma is quite low for both tanners and non-tanners." The Federal Trade Commission recently charged the Indoor Tanning Association with exaggerating the benefits of indoor tanning and falsely denying the associated skin-cancer risks. In 2005, Consumer Reports surveyed almost 300 tanning salons nation-wide, and found that more than 30 percent of salon personnel denied that tanning beds could cause skin cancer.
How sound is the study? Dr. Allan Halpern, vice president of the Skin Cancer Foundation and chief of dermatology service at Memorial Sloan-Kettering Cancer Center in New York City, says: "Together with the recently published extended follow-up of a large Norwegian-Swedish cohort, these data strongly support the conclusions of the International Agency for Research on Cancer that artificial UV tanning devices are carcinogenic in humans...We hope that these findings, along with what we already know about the risks of indoor tanning, will keep people from using tanning beds. We also hope this additional data will motivate the FDA to expedite appropriate regulation of these devices." Dr. Lynn Drake, a dermatologist at Massachusetts General Hospital, in Boston, and a nonvoting member of the FDA panel on indoor tanning, says: "This new study adds to the body of evidence supporting the fact that indoor tanning poses significant risks... A healthy tan is an oxymoron. A tan is simply a response to injury, whether it's obtained indoors or outdoors."
The study data is particularly timely, as information on the dangers of tanning beds is not always well understood. The Suntelligence self-selected tanning survey by the American Academy of Dermatology (you can take it here), discussed by MedPage Today, shows that less than 48% of respondents know that getting a base tan is not a healthy way to protect skin from sun damage, and that only 35% of adults know that there are no UV rays that are safe for your skin.
A compounding issue is that users of tanning beds appear to show addiction symptoms in troubling numbers. A study from researchers Memorial Sloan Kettering Cancer Center and University of Albany, published in April 2010 in Archives of Dermatology, show that 30 to 40% of tanning bed users met criteria for addiction, as discussed by Medline, and Consumer Report. A similar study led by researchers at University of Washington, published in the March 2007 issue of the Journal of the American Academy of Dermatology, and discussed in Science Daily and WebMD, reported that 28% of indoor tanners surveyed met criteria for addiction. Another study published in the April 2006 issue of the Journal of the American Academy of Dermatology even showed that frequent tanning salon users who are given naltrexone, an endorphin-blocking substance, get withdrawal symptoms, while infrequent users do not.
In 2009, the International Agency for Research on Cancer (a part of the World Health Organization, WHO) classified tanning devices as carcinogenic. The FDA recently warned about the risks of indoor tanning -it produced a video about it,- and is considering banning the use of tanning beds for minors. In March, its advisory panel recommended that indoor tanning require parental consent for minors, that tanning beds be regulated more stringently, and that bolder labels be required on tanning beds. The American Association of Dermatology recommends banning tanning beds for non-medical purposes. The 2010 health reform included a 10% tax on tanning salons.
What healthy alternatives do you have to tanning beds? The American Cancer Society advises people to use sunless self-tanning creams, lotions or sprays. My wife uses them every year: she comes out of her 45-minute self-tanning spray appointment as dark as I am at the end a a long, sunny summer - and a lot better looking:-)
Want to read more about it? Check CNN, USA Today, Medical News Today, CTV, Canoe, NPR, HealthDay/ Business Week, Wall Street Journal, WebMD, US News & World Report, Health News, eMaxHealth, ConsumerReports,
University of Minnesota Press Release
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