SUNDAY July 13, 2008 (foodconsumer.org) -- The prevalence of a form of deadly skin cancer called melanoma has been on the rise particularly in younger women, according to research by federal scientists, cited by Washington Post.

The study of government cancer data from 1973 through 2004 showed that the rate of new melanoma cases in younger women had increased 50 percent since 1980, did not increase in younger men during the same period.

The findings were published in the Journal of Investigative Dermatology.

The researchers did not know how to explain why more young women now than ever had been diagnosed with melanoma.

They said it's unlikely that the high rate was due to better screening and speculated that it's due likely to younger women's increased exposure to ultra-violet rays on the beach or tanning salons.

Ultraviolet rays including A, B and C are recognized as carcinogen and doctors linked the exposure to these radiations to high risk of skin cancer including the deadliest form of skin cancer melanoma.

"One possible explanation is increases among young women of recreational sun exposure or tanning bed use," said Mark Purdue, a research fellow at the National Cancer Institute, who led the research.

"Both of these things have been identified as risk factors. It's possible increases in these two behaviors may be responsible."

Melanoma is diagnosed in about 62,000 people and kills 8,400 of them in the United States each year, according to the National Cancer Institute.

The overall rate of melanoma is on the rise. But the current study focused on younger adults.

Specifically, the researchers found for young men, the rate of new melanoma cases increased to 7.7 per 100,000 per year in 1980 from 4.7 cases per 100,000 per year in 1973.   But the rate leveled off afterwards.

Purdue said in an e-mail, cited by Washington Post that the reason for the level-off is unknown, but "This may reflect reductions over time in the amount of sun exposure experienced by young men (public awareness campaigns regarding sun exposure and melanoma were widely launched in the US in the 1980s). However, we really don't know for sure."

In comparison, for young women, the melanoma rate rose to 9.4 per 100,000 in 1980 and 13.9 in 2004 from 5.5 cases per 100,000 per year in 1973.

The increase unlikely resulted from increased awareness and diagnosis because many cases were found in later stages, Purdue was cited as saying.

He suggested the possible reason for the consistent increase in the rate of melanoma among young women is that younger women are more likely than young men to use sunscreens, which may “ironically” increase these women's exposure to ultraviolet rays.

C. William Hanke, president of the American Academy of Dermatology was cited by Washington Post as saying the results should remind young women of the danger of unprotected outdoor sun exposure and indoor tanning.

The tanning industry disputed the claim.   Sarah Longwell, a spokeswoman for the Indoor Tanning Association was cited as saying that people who talk about indoor tanning as a cause of melanoma have not looked at the science on the subject.

She said "There have been no scientific studies that show that indoor tanning causes melanoma."

Mr. Örjan Hallberg, founder and senior researcher of Hallberg Independent Research in Sweden, conducted some epidemiological studies and found that increase rates of melanoma are associated with exposure to radio waves and high rates were found near radio and TV towers.

He disputed the common notion that increased rate of melanoma is attributed to increased exposure to ultraviolet rays.

Naturalnews.com reported citing UK research that sunscreens may actually increase risk of melanoma for two reasons. First, sunscreens block ultraviolet rays and reduce production of anti-cancer vitamin D.   And second, many sunscreens contain toxic chemicals.

Experts have warned that excess exposure to sunlight or ultraviolet rays in tanning salons can increase risk of skin cancer, but blockage of exposure to the radiations can lead to deficiency of vitamin D, which can increase risk of more dangerous forms of cancer.