(HealthDay)—Many people make mistakes when using sunscreen that could increase their risk of skin cancer, a new study suggests.
Researchers set up free sunscreen dispensers at the Minnesota State Fair and watched as nearly 2,200 people used them.
The researchers found that only 33 percent of people applied sunscreen to all exposed skin. Only 38 percent were wearing sun-protective clothing, hats or sunglasses. Also, use of the free sunscreen dispensers fell sharply on cloudy days, the researchers reported.
The study was published online May 16 in the Journal of the American Academy of Dermatology.
"These results highlight some of the ways people use sunscreen incorrectly," study author Dr. Ingrid Polcari said in a journal news release. She is an assistant professor in the department of dermatology at the University of Minnesota Medical School.
"To get the best possible sun protection, it's important to wear protective clothing, such as long-sleeved shirts and pants, and to apply sunscreen to all exposed skin, not just your face and arms," Polcari explained.
"Everyone should apply sunscreen every time they go outside," she added. "Even on cloudy days, up to 80 percent of the sun's harmful UV rays can reach your skin."
The study also found that more women than men took advantage of the free sunscreen. Fifty-one percent of fairgoers were women, but they accounted for 57 percent of the free sunscreen users.
"Research has shown that women are more likely than men to use sunscreen, but it's vital that men use it, too," said Dr. Darrell Rigel, a clinical professor in the department of dermatology at New York University.
"Men over 50 have a higher risk than the general population of developing melanoma, the deadliest form of skin cancer, and UV exposure is the most preventable skin cancer risk factor, so it's important for men of all ages to protect themselves from the sun's harmful rays by seeking shade, wearing protective clothing and applying sunscreen," Rigel said.
When choosing a sunscreen, Rigel suggests the following tips:
- Choose a sunscreen with an SPF 30 or higher. A sunscreen with SPF 30 blocks 97 percent of the sun's UVB rays.
- Look for the words "broad spectrum." This means the sunscreen protects against both UVA rays (which cause premature skin aging) and UVB rays (which cause sunburn). Both types of UV rays can lead to skin cancer.
- Look for the words "water resistant." Water-resistant sunscreens can provide protection for wet or sweaty skin for 40 or 80 minutes. All sunscreens should be reapplied every two hours, or after swimming or sweating.
- For sensitive skin, choose a sunscreen with zinc oxide or titanium dioxide. People with sensitive skin also should avoid sunscreens that contain fragrance, oils and para-aminobenzoic acid, also known as PABA.
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The U.S. Centers for Disease Control and Prevention has more on sun safety.