Rates of melanoma, the deadliest form of skin cancer, have been increasing steadily for the past two decades, growing, on average, 3.5 percent every year since 1992, according to the American Melanoma Foundation. In an almost direct parallel, sales of sunscreen have been growing at a pace of about 4.2 percent per year during the same time period. So if we're using more sunscreen and still getting more melanoma, there must be something else at play.
A number of recent studies could explain why we're seeing more skin cancer—and it's not because of our love affair with beach vacations. Here are three risk factors that don't get much attention in broader conversations about skin cancer. The good news? You can do something to protect yourself from every one.
#1: Climate Change
Researchers from Harvard University have discovered that our warming planet is also contributing to a thinning of the ozone layer, a part of the stratosphere that, when it's healthy, blocks out most of the ultraviolet (UV) radiation responsible for causing skin cancer. Climate change is driving stronger and stronger storms, which in turn lead to a buildup of water vapor in the atmosphere. That water vapor reacts with elements that exist naturally in the air and produces chlorine, triggering a cancer-causing chemical reaction. "One atom of chlorine can destroy more than a hundred thousand ozone molecules," says Linda Marsa, contributing editor at Discover magazine and author of the forthcoming book, Fevered: Why a Hotter Planet Will Hurt Our Health and How We Can Save Ourselves (Rodale, 2013). As the ozone layer gets thinner, more damaging UV rays will reach your skin, she adds, which could lead to an increase not just in rates of skin cancer but also of cataracts.
Protect Yourself: Cover up! The most effective way to deter UV-related skin damage is to wear long sleeves, pants, and other effective sun-protection clothing. And grab your sunglasses to protect your eyes from UV damage (here are more tips on how to protect your eyes from the summer sun).
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#2: Your Office Lights
Running inside to dodge the sun may not protect you either, according to scientists from the State University of New York, Stony Brook. A small study they conducted on human skin cells found that healthy cells appear to react to radiation emitted by compact fluorescent light bulbs (CFLs) the same way they do to sunlight, by increasing production of cancer-causing free radicals. But cells don't react that way to the radiation emitted by regular incandescent bulbs or even to overhead tube fluorescent lights.
Protect Yourself: Keep your CFLs at arm's length, suggests study author Miriam Rafailovich, PhD, professor in the department of material science and engineering. "You shouldn't sit closer than a foot to these bulbs." And, she adds, use glass lampshades if you can, as those filter more radiation than cloth or plastic ones. Finally, make use of natural light as much as you can.
#3: Your Sunscreen
It's ironic that the lotion you're slathering on to ward off skin cancer may be putting you at greater risk for…skin cancer. But sunscreens that contain vitamin A, or retinol, may be doing just that. The ingredient is added to a number of sunscreens and skin lotions because of evidence that it slows aging. However, a 2009 study by researchers with the government's National Toxicology Program found that vitamin A applied to the skin in the presence of sunlight sped the development of skin tumors and lesions. Two years later, the Food and Drug Administration (FDA) published an analysis of research on vitamin A concluding the same thing. Consumer advocates have been pushing the agency to restrict the use of vitamin A in topical products, but the FDA has remained mum on the subject.
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Protect Yourself: Read ingredients labels and opt for products that don't contain vitamin A. Interestingly, though, some evidence suggests that taking vitamin A supplements orally could actually protect you. Kaiser Permanente researchers published a study finding that women taking a vitamin A supplement containing 1,200 milligrams of the vitamin saw a 60 percent reduction in melanoma risk. But first talk to your doc about taking vitamin A, as too much can be toxic, causing liver failure and even death. Kaiser's researchers published a similar study finding that a daily aspirin reduced melanoma risk by 21 percent.