Given that indoor tanning beds were officially classified as a human carcinogen in 2009 -- up there with cigarettes and asbestos -- it should be fairly obvious that frequent tanning-booth exposure would increase your risk of skin cancer.
Indeed, the evidence linking indoor tanning with melanoma, the deadliest form of skin cancer, and squamous cell carcinoma, one of the more common forms of the disease, is "convincing," according to the World Health Organization's International Agency for Research on Cancer. But the research concerning tanning beds and basal cell carcinoma, the third and most frequent major type of skin cancer -- which accounts for some 80% of all skin cancer cases in the U.S. -- has thus far been inconsistent. (See pictures of a photographer's intimate account of her mother's cancer ordeal.)
Basal cell carcinoma, a slow-growing cancer, has traditionally been a disease of middle age. But it's been appearing with increasing frequency in people under 40, especially in women -- a demographic that also happens to like indoor tanning -- suggesting a link. So researchers at the Yale School of Public Health sought to study the association.
The study included 376 people under 40, who had been diagnosed with basal cell carcinoma between 2006 and 2010. They were matched with a control group of 390 dermatology patients who were diagnosed with minor skin conditions like cysts and warts. All participants had skin biopsies, and all were drawn from a Yale University database.
The researchers interviewed each participant about their UV exposure -- both in tanning beds and outdoors. They also asked about their history of sunburns, sunscreen use, family history of melanoma and non-melanoma skin cancers, and their self-reported eye, skin and hair color.
The conclusion: people who had ever used a tanning booth were 69% more likely to develop early-onset basal cell carcinoma than never tanners. Those who used tanning booths more regularly -- for at least six years -- were more than twice a likely to develop basal cell carcinoma, compared with never tanners.
The study found that women were far more devoted than men to indoor tanning, which might help explain why 70% of all early onset basal cell carcinomas occur in females. The authors concluded that about 27% of cases of early onset disease -- including 43% of cases in women -- could be prevented if people simply stopped using tanning booths.
That's a tall order, considering that some 30 million Americans use indoor tanning beds each year. Policy changes, such as the recent California ban on teen tanning, may help, the authors suggest. So would behavioral interventions aimed at women -- at least one study in 2010 found that the best way to get young women to tan less was to warn them about the skin-wrinkling effects of tanning-bed exposure, not the risk of skin cancer.
"Importantly, indoor tanning is a behavior that individuals can change. In conjunction with the findings on melanoma, our results for [basal cell carcinoma] indicate that reducing indoor tanning could translate to a meaningful reduction in the incidence of these two types of skin cancer," said Leah M. Ferrucci, first author of the paper and a postdoctoral fellow at the Yale School of Public Health, in a statement.
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