Moths to Flame: Tanners Drawn to Sun’s Dangers
When it comes to cholesterol, alcohol and cigarette smoke, Americans are following the advice of medical experts and moderating their intake. But when it comes to sunlight, people just can’t seem to get enough, even though the link between sun exposure and skin cancer is widely known.
Nearly all of the 500,000 cases of skin cancer reported nationwide each year are sun-related, which makes it one of the most preventable of all cancers. When caught in its early stages, it is perhaps the most curable cancer.
Unfortunately, skin cancer also is one of the fastest-growing cancers. Its most serious form, malignant melanoma, is spreading more quickly than any other cancer except lung cancer in women, which coincides with increases in cigarette smoking among women.
Physiologically Dependent
Like sunbathing, smoking is a habit that people hate to love. Surveys have shown that the vast majority of smokers want to quit because they are afraid of developing cancer. But most do not quit because they become physiologically dependent on nicotine, tobacco’s psychoactive ingredient.
“Nicotine itself is an addicting drug,” said Dr. Jack Henningfield of the National Institute on Drug Abuse. “It is more potent than cocaine in modifying behavior and it has intoxicating effects that are as powerful as most barbiturates.”
Sunbathers, like smokers, also find it difficult to break the habit. This year, in a survey conducted for the American Academy of Dermatology, nearly all the adults who responded agreed that sun exposure damages the skin, and more than half knew about the link between sunbathing and skin cancer.
But one-third of those surveyed said they intentionally work on a tan each summer and one-fourth said they do not use any kind of sunscreen while out in the sun.
The passion for sunlight is so great that tan fanatics can indulge their habit at night or under cloudy skies, thanks to the growing network of tanning parlors. And those who are short on time can now buy lotions that claim to accelerate the tanning process by altering the body’s natural pigments.
Habits Not Influenced
“We’ve gotten the message across that excessive sun exposure is bad for our looks and our health,” said Dr. Richard Odom, academy president, “but that doesn’t seem to be strongly influencing people’s habits yet . . . (because) people believe it won’t happen to them.”
Frustrated skin care experts aren’t sure why the pleasures of sunbathing outweigh the obvious health risks. Most cite cosmetic reasons--ironically, a suntan is considered a healthy look--and blame the sun habit on vanity and naivete.
“We are all humans; we all want to have our cake and eat it too,” said Dr. Sergio Nacht, a California biochemist who works on developing new sunscreens. “We want to avoid cancer, but we also want to look nice and tanned.”
People also may persist in sunbathing because it makes them feel good. There is evidence from studies of psychiatric patients that sunlight elevates mood by regulating the synthesis of brain chemicals that oversee body rhythms.
In fact, people who suffer from what is called “seasonal depression,” a cycle of high energy and enthusiasm in the summer and lethargy in the winter, have actually been treated with regular exposure to a bank of artificial full-spectrum lights.
“Bright light does seem to have an antidepressant effect,” said Dr. Thomas Wehr of the National Institute of Mental Health, who developed the experimental treatment. “We’re not sure exactly how it works, but we think it is modulated through the eyes directly to the brain’s hypothalamus, which governs mood and emotion.
“And heat, up to a point, can have a tranquilizing or sedative effect, like the feeling you get when you take a hot bath,” Wehr added. “So the sun gives you a combination of light’s antidepressant effect and heat’s tranquilizing effect. That’s already plenty of reason for people to lie out in the sun.”
If there were evidence that sunbathers become dependent on sunlight’s psychoactive effects, a chemical substitute, like nicotine chewing gum, might help wean people away from the beaches and the tanning parlors.
But breaking the sun habit just isn’t that simple. Skin care experts agree that, as long as people want to lie in the sun, the best way to prevent skin cancer is to use sunscreens.
Nearly every available sunscreen lotion, cream, oil or gel is labeled with an SPF (sun protection factor) number, ranging anywhere from 2 to 34, and the higher the number, the greater the protection. Most skin care experts recommend wearing a sunscreen product with an SPF factor of at least 15.
The basic unit of measurement for the SPF system is the “minimum erythemal dose,” Nacht said, and this is simply “the amount of time you need in the sun to generate minimum color without turning red.”
When radiation from the sun’s ultraviolet rays hits the epidermis, Nacht said, skin cells try to protect themselves by synthesizing melanin, a pigment that darkens the skin. The sun’s UVB rays, which primarily affect the epidermis, eventually produce sunburn and are the chief cause of skin cancer. UVA rays, which penetrate more deeply, produce suntan and premature aging.
After prolonged exposure to both UVA and UVB rays, Nacht said, “the skin cells’ genetic material, or DNA, eventually becomes influenced by all that radiation. Some of the cells may lose control, begin dividing at random and become cancerous.”
Sunscreens contain ingredients with “special chemical structures that have the ability to absorb particular wavelengths,” Nacht said. Formulas with PABA derivatives siphon off UVB rays and those with benzophenones absorb UVA rays. The most effective products, he said, are so-called “full-spectrum” sunscreens that incorporate both types of protection.
Dr. Diana Bihova, a New York University Medical Center dermatologist, emphasized that no sunscreen can completely block out the sun’s rays. Unfortunately, “most consumers think an SPF-15 sunscreen means ‘no tan,’ ” she said, and many mistakenly opt for weak sunscreens.
“Well, you can still tan,” she warned, “and any tan is damaging.”
Total Sun Block Needed
Bihova, who advises the American Academy of Dermatology on sunscreen usage, thinks the only real hope of preventing skin cancer lies in the development of “a total sun block” that has the potency of zinc oxide (available in thick, opaque ointments) but is easier to apply and less irritating to the skin.
Such a product does not yet exist, she reported, even though several companies have marketed high-SPF formulas as “superblocks” that “are supposed to let you stay in the sun all day long.
“That word is a misnomer,” Bihova said. “They may be super sunscreens, but they’re not superblocks, and if you’re swimming or perspiring, you need to reapply them.”
Until an effective, easy-to-apply sun block is available, Bihova tells her fair-skinned patients to avoid sunlight as much as possible. If they want to look tanned, she advises them to use tinted moisturizers or self-oxidizing lotions that darken outer skin cells without inflicting damage.
And, like most skin care experts, Bihova wishes consumers would learn to apply sunscreens as regularly as they use deodorants and toothpaste.
“People should realize that they need to use sunscreens every day, winter and summer,” she said. “Sunscreens are so easy to apply that it’s really just a question of habit.”
Dermatologists are not giving up their campaign to wean Americans from their desire for the sun. But they are taking a different tack and focusing education efforts on fledgling sunbathers and their parents.
Childhood Use Promoted
This year, the American Academy of Dermatology is working with the American Academy of Pediatrics to promote the use of sunscreens during infancy and childhood.
Their national campaign was prompted by growing data that sunscreen usage early in life can drastically reduce the risk of skin cancer in adults.
“There is strong evidence that if your parents start applying sunscreen to you as an infant and you use it throughout your life, you can reduce your risk of cancer by over 90%,” Odom said. “If that’s true, it’s a very compelling statistic.”
Older Americans, another target population, are receptive to messages about the dangers of sunbathing because cumulative sun damage becomes all too apparent later in life.
“A lot of my patients who used to sunbathe vigorously are now saying, ‘I see wrinkles and irregular pigmentation, and that’s enough,’ ” Bihova said.
