Study: Indoor Tanning Increases Skin Cancer Risk

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With an international health group declaring indoor tanning booths carcinogenic in 2009, you might think that studies connecting indoor tanning and skin cancer are pretty well established.

As it turns out, studies on the subject are sparse, and the few that exist have not done a good job of analyzing the differences among tanning machines and the potential relationship between frequency of use and the risk of developing cancer.

Now, in a report in a journal of the American Association for Cancer Research, scientists at University of Minnesota have addressed those deficiencies in the data with the first controlled study of indoor tanning and the risk of melanoma. The researchers began with more than 2000 individuals, half of whom had documented cases of melanoma, and half whom did not, and asked them about their tanning habits, which included questions about their outdoor sun exposure as well as use of indoor tanning equipment. Lifetime exposure to outdoor sunlight, whether through jobs or leisure activities, was not associated with an increased risk of developing skin cancer, but use of tanning beds was. Those who tanned indoors had a 74% greater risk of developing melanoma than those who never used the machines.

The authors also documented a rise in risk of cancer with use of particular tanning machines — those taking advantage of UVA radiation beds increased their risk of melanoma 4.4-fold over those who never used the devices. UVA based tanners emerged in the 1980s after data suggested that UVB rays were predominantly responsible for causing skin cancers and before more recent studies linking both types of radiation exposure to melanoma.

While the international report warned against the frequent use of indoor tanners among young people, who the authors suggested might be at greater risk of developing skin cancer because of their age, the current study suggests that it’s not their age per se but the number of years that they are exposed to indoor tanning rays that pose the biggest cancer risk to teens. The more years spent tanning, in other words, the greater the chances that youngsters will develop skin cancer.

That’s why the Food and Drug Administration began in March to consider stricter regulation of indoor tanning use, particularly among teens. An advisory committee for the agency was divided at the time over whether the scientific evidence supported the need for a complete ban on exposure for children under 18, or whether parental approval was sufficient to protect youngsters from the long term effects of not just skin cancer but premature aging and damage to the eye and immune system. This study will undoubtedly provide some important data for making that decision.