Oct. 16, 2003 -- There's more evidence on the hazards of tanning beds. Baking under their artificial lamps as little as once a month can boost your risk of a deadly form of skin cancer by 55% -- and the danger is even greater when done in early adulthood.
A new study involving more than 106,000 Scandinavian women shows what its researchers say is the strongest evidence to date that artificial tanning can cause malignant melanoma.
Past research shows tanning beds raise risk of other types of skin cancer. Last year, Dartmouth researchers reported that people who ever visited a tanning salon were 2½ times more likely to later get squamous cell skin cancer and 1½ times more likely to develop basal cell skin than those who didn't.
When malignant melanoma is detected in its earliest stages, surgical removal cures the cancer in most cases. If the disease spreads survival at 5 years after the diagnosis is only about 30% to 40%. There are a number of factors that increase the risk of melanoma -- a family history, prominent or unusual moles; overexposure to ultraviolet radiation in sunlight is believed to contribute to melanoma in some cases.
For this study, published this week in the Journal of the National Cancer Institute, the Swedish and Norwegian women completed detailed questionnaires in 1991 and 1992 about personal characteristics such as their hair and eye color, the number of moles on their body, and their histories of sunburn and tanning patterns -- whether under natural sunlight or in tanning salons. Researchers tracked their rates of melanoma eight years later and found 187 cases of melanoma.
They find that eye color was not associated with increased risk. "We also found no statistically significant association between tanning of the skin after heavy or repeated sun exposure and the risk of melanoma," write researcher Marit Veierod and colleagues.
But no matter the women's age or hair color -- considered by some to be predictors of later melanoma risk -- the researcher say that women who visited a tanning parlor at least once a month were 55% more likely to later develop melanoma than women who didn't artificially suntan. Those who used sun lamps to tan while in their 20s had the greatest later risk, about 150% higher than similarly aged women who shunned tanning beds.
The risk from melanoma from sun exposure was four times greater in red-haired women, who are typically fair-skinned compared with women with dark brown or black hair. Blondes had twice the risk compared with women with brown or black hair.
These new findings are important, because it's hard to study what specific factors increases the risks of melanoma and other types of skin cancer. Because mice don't get these forms, researchers must rely on these types of population studies that track lifestyle habits and later disease rates, says James Spencer, MD, spokesman for the American Academy of Dermatology and vice chairman of dermatology at Mount Sinai School of Medicine. He was not involved in this study.
"In a way, it's confirming the obvious," he tells WebMD. "We know that ultraviolet light from the sun causes skin cancer, and we presumed that ultraviolet light from tanning salons also causes skin cancer, although there's no direct experimental way to show that."
But he says he's surprised by the risk noted in women who artificially tanned.
"We knew artificial tanning was bad, but it's worse than we thought. This is a large, powerful study and I think what it does is confirm what we suspected."
But Indoor Tanning Association spokesman Joseph Levy says the new findings don't apply to Americans.
"We don't know anything specifically about how or where this tanning equipment was used," he tells WebMD. "Indoor tanning in Scandinavia is not regulated like it is here. They don't have exposure schedules or the same type of equipment. You're talking about a fair-skinned population that has a different mentality -- they are sun worshippers."
So does he think that tanning beds are safe?
"Being safe implies that you can do something recklessly and not think about what you are doing to maximize benefits and minimize risks," says Levy. "We want people to think about what they're doing when tanning, as opposed to just saying 'safe.'"
Last month, the Archives of Pediatric and Adolescent Medicine reported that in a survey of 7,000 teenagers, one in three girls and 11% of boys say they had used an indoor tanning bed at least once in their life.