If you're confused about the health effects of indoor tanning, rest assured: You're not alone. For decades, the American Academy of Dermatology, the Skin Cancer Foundation, and other medical groups have pounded home the message that it's a dangerous practice and should be avoided. An ominous video, for example, from the American Academy of Dermatology's ongoing Tanning Is Out campaign says that every hour one person dies from melanoma, a particularly lethal form of skin cancer, implying that ultraviolet radiation from indoor tanning is to blame. Many dermatologists suggest that the tanning industry, like the tobacco industry before it, is manipulating and distorting scientific evidence to protect a dangerous product.
But buttressed by the growing evidence that high levels of vitamin D may be important for overall health, the Indoor Tanning Association is now aggressively campaigning to discredit all attackers. In full-page ads (.pdf) in the New York Times, the industry group has argued that the link between ultraviolet light exposure and melanoma is hype; in a nationally distributed television ad, it has accused dermatologists of needlessly scaring people from getting the beneficial health effects associated with the sun; and a website (.pdf) created by the group savages dermatological groups for having conflicts of interest with cosmetic and sunscreen makers.
In fact, as common sense suggests, tanning is neither an entirely dangerous nor a largely healthful activity. Small amounts of exposure to ultraviolet radiation enhance vitamin D production; regular tanning can lead to premature aging, cataracts, and skin cancers. The question, of course, is how much sun is too much. And that's where it gets complicated. "There is no such thing as a recommended amount of sun exposure that will apply equally to everybody," says Bernard Ackerman, the emeritus director of the Ackerman Academy of Dermatopathology, a diagnostic laboratory and teaching facility in New York City. Here's what you need to keep in mind in figuring out the right amount for you:
1. Your natural skin tone—and its ability to tan without burning—have a strong impact on your cancer risk. People with darker hair and skin have more melanin, a pigment that acts as a natural sunscreen and hampers ultraviolet radiation's ability to damage the DNA of skin cells. Research has shown that the risk of skin cancers increases with decreasing levels of pigmentation, so that redheads face the greatest risk, followed by blonds, and then people with brown and finally black hair. Though it isn't unheard of for people with darker complexions to get melanoma, the American Cancer Society estimates that the risk is 10 times as great among Caucasian Americans as among African-Americans. Having lots of moles increases risk even further, as do age and having a family history of the disease.
2. Your base skin tone, as well as your age, also i nfluences vitamin D levels. There's still debate about how much vitamin D is optimal and how strongly it actually influences health, but emerging research suggests that large percentages of Americans are dangerously deficient—though the groups most likely to be deficient aren't those known for frequenting tanning parlors. Vitamin D production slows with age, so older Americans are particularly likely to have low levels. The same pigments that block damaging ultraviolet radiation also hamper vitamin D production, so people with a naturally dark complexion have a higher likelihood of being deficient. One study found that 12.2 percent of African-American women were deficient in vitamin D, compared with 0.5 percent of white women.
Ask your doctor for a simple blood test to know for sure if you need more vitamin D, suggests Michael Holick, an endocrinologist and professor of medicine, physiology, and dermatology at Boston University. To avoid the risk from sun exposure entirely, many doctors recommend taking a daily supplement of between 1,000 and 2,000 international units to boost vitamin D levels. Food also contains small levels of vitamin D, but it can be difficult to get enough of the vitamin from food alone.
3. There's more than just melanoma to worry about when it comes to sun exposure. Dermatologists disagree, as the Indoor Tanning Association campaign suggests, about whether ultraviolet light exposure directly causes melanoma. Other factors, such as a person's genetics or exposures to chemicals in the environment, may also play a role. Though melanoma often commands the most attention, squamous cell carcinoma, another type of skin cancer that is definitely caused by overexposure to ultraviolet light, accounts for about a third of the fatalities associated with skin cancer, warns David Fisher, an oncologist at the Dana-Farber Cancer Institute. Furthermore, dermatologists warn that treatment for nonlethal types of skin cancer, such as basal cell carcinoma, can be disfiguring. Finally, there's no dispute that sun exposure causes wrinkling, drying, and other signs of aging skin.
4. Just a few minutes will do it. Many dermatologists, such as Boston University's Barbara Gilchrest, are quick to point out that, for fair skinned people in Boston, no more than five minutes of sun exposure during a sunny June day is often all that's needed to get enough vitamin D. In fact, she says, production of the vitamin often peaks and ceases after just a few minutes of sunlight exposure, after which only damage occurs. During the winter, however, she recommends taking a supplement; at latitudes greater than about 35 degrees, the light isn't intense enough for the body to produce any vitamin D.
Tomorrow: Men Need to Look f or Skin Cancer Before It Spreads