Their results were published online on May 27, 2010 in the journal Cancer Epidemiology, Biomarkers and Prevention. The title of the paper is 'Indoor Tanning and Risk of Melanoma: A Case-Control Study in a Highly Exposed Population.'
Although many studies have been performed on the link of indoor tanning with increased risk for melanoma, few of these studies examined the specifics as to 'why' cancer happens more frequently when people use indoor tanning devices.
Because previous scientific studies did not study "why" cancer happens more frequently with increased use of indoor tanning (only that it "does"), the Lazovich team decided to look into specific details concerning indoor tanning and cancer.
Specifically, they looked at sun exposure, dose-response, and different types of tanning devices as possible reasons why people who use indoor tanning are at higher risk of developing melanoma.
The U.S. researchers studied cases of 'invasive cutaneous melanoma' diagnosed in Minnesota between 2004 and 2007.
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The researchers sent out questionnaires for 1,167 subjects with melanoma to fill out.
They also randomly telephoned 1,101 control subjects without melanoma and asked them questions pertaining to indoor tanning, such as type of tanning device they used and the type of radiation used within the devices, burns caused by tanning, amount of time used for tanning, and other such essential information.
They then called each subject in order to substantiate lifestyle habits for each group, the melanoma group and the control group.
The researchers wanted to differentiate between the two groups with respect to such factors as eye color, number of moles, sun exposure, sunscreen use, family history of melanoma, and skin tone.
Of a total of 1,167 cases involving invasive cutaneous melanoma, along with another 1,101 control cases, they found that 62.9% of the melanoma cases and 51.1% of the control cases had used indoor tanning devices'”about 11.8% more of the people who had melanoma (had used indoor tanning) than those who didn't have the skin cancer.
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The researchers also found that using an indoor tanning device for 50 or more hours increases one's risk of melanoma by three times.
And, for those who had used an indoor tanning device or only six hours were at double the risk of melanoma than those who had never used it.
They also found that users of primarily ultraviolet B (UV-B) radiation for the tanning devices had a slightly higher risk of melanoma than users of primarily UV-A radiation.
The researchers also found that the risk of getting melanoma increased with use, both in the number of hours used, number of years used, and the number of sessions used.
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They also stated, 'This study overcomes some of the limitations of earlier reports and provides strong support for the recent declaration by the IARC that tanning devices are carcinogenic in humans.'
Carcinogenic means 'cancer-causing.'
For additional information on indoor tanning, please read the article 'The Truth About Indoor Tanning,' from the American Osteopathic Association (AOA), and the article 'Indoor Tanning: The Risks of Ultraviolet Rays,' from the Food and Drug Administration (FDA).