A dramatic spike in skin cancer rates among young adults in the U.S. can largely be blamed on the use of tanning beds, a new study suggests.

For their study, researchers from the world-renowned Mayo Clinic reviewed decades of patient-care data from Olmsted County, Minn. They narrowed their focus to first-time diagnoses of melanoma, the most dangerous form of skin cancer, in patients aged 18 to 29. They included data from 1970 to 2009.

They found that incidents of melanoma have risen eight-fold among women in that age group, and risen four-fold among men.

The findings are published in the April edition of Mayo Clinic Proceedings.

Lead researcher Dr. Jerry Brewer, a dermatologist at the Mayo Clinic, said his team expected to find rising rates of melanoma, in keeping with the latest studies. However, the incidence rates in his study outpace those reported by other research.

Brewer said his team believes the use of indoor tanning beds is the primary reason skin cancer rates are on the rise among young women.

"A recent study reported that people who use indoor tanning beds frequently are 74 per cent more likely to develop melanoma, and we know young women are more likely to use them than young men," Brewer said in a statement.

"The results of this study emphasize the importance of active interventions to decrease risk factors for skin cancer and, in particular, to continue to alert young women that indoor tanning has carcinogenic effects that increase the risk of melanoma."

The researchers noted that childhood sunburns and overall exposure to ultraviolet light in adulthood were possible contributing factors to melanoma, as well.

The findings are in step with data released last week showing that while overall cancer rates in the U.S. are on the decline, skin cancer diagnoses are on the rise. That report, which was a collaborative effort among four agencies, including the U.S. Centers for Disease Control and Prevention and the American Cancer Society, also found an increase in deaths from skin cancer, unlike the Mayo Clinic study.

"I think this is a future epidemic in the making," Dr. Marcus Plescia, director of the CDC's division of cancer prevention and control, said last week.

In contrast, the Mayo team did report a decline in melanoma mortality rates, a finding they attributed to early detection and prompt treatment.

"People are now more aware of their skin and of the need to see a doctor when they see changes," Brewer said. "As a result, many cases may be caught before the cancer advances to a deep melanoma, which is harder to treat."

Tanning bed bans

The research comes as a number of jurisdictions seek to ban young people from tanning beds, given the growing body of research that links them with skin cancer.

Last year, Nova Scotia became the first province to ban anyone under age 19 from using a tanning bed. Last month, British Columbia announced plan to introduce legislation to ban anyone under 18 from using tanning beds.

France, Scotland and England have all banned the use of tanning beds among youths under age 18, as has the state of California.

Tanning industry advocates say rather than outright bans, better controls should be put in place, including exposure limits on youth, and a ban for people with certain skin conditions.

Melanoma is a skin cancer that begins in the epidermis, the skin's upper layer, in cells called melanocytes. These cells produce melanin, which is what gives the skin its colour.

While melanomas don't all appear the same, signs to look for include a mole that is asymmetrical, has irregular borders or jagged edges, is more than one colour and is larger than 6 millimetres in diameter, and oozes or bleeds.