When it comes to sunscreen use, how often you put it on may matter more than what you put on, according to new research presented by a dermatologist Wednesday.
"Use of sunscreen with frequent re-applications appears to be one of the most effective and effortless methods of sunburn protection," said Dr. Darrell Rigel, a dermatologist and professor at New York University Medical Center.
Rigel tracked sun exposure and sunscreen use by 105 skiers in Vail, Colo., over one week in January. Each participant was given an unmarked bottle of sunscreen (either Sun Protection Factor 15 or 30) and asked to keep a log of time spent outdoors, as well as the amount of sunscreen applied.
According to Rigel, snow-covered slopes are an ideal laboratory for sunburn research. "A skier on an average day receives more than three times the ultraviolet radiation exposure necessary for sunburn," he said. UV intensities at 8,000 to 11,000 feet are known to be 60 percent to 80 percent higher than at sea level for the same latitude. And the reflection of the sun can add up to 40 percent additional ultraviolet intensity.
In this intense environment, those who reapplied sunscreen every 2.5 hours or more frequently were five times more likely to sunburn than those who applied sunscreen every two hours or more, said Rigel, who reported his research during a news conference sponsored by the American Academy of Dermatology in New York.
"Most people know that the sun's rays are dangerous, but that does not always translate into recognizable protective actions, Rigel said. "Although this study surveyed those who enjoyed winter sports, the findings should be applied to all who enjoy the outdoors.
"These results also confirm the need for regular UV protection to minimize subsequent lifetime melanoma risk," he added.
Earlier studies have shown that sun exposure is responsible for the development of at least two-thirds of all melanomas, the deadliest form of skin cancer. It is estimated that more than 51,000 Americans will be diagnosed with melanoma this year, and another 7,800 people will die from this form of cancer. Sunburn also plays a role in other types of skin cancer, which strikes about a million people each year.
The dermatologists and the Skin Cancer Foundation both recommend that people use a broad-spectrum sunscreen with SPF of 15 or higher and use it any time you're going to be in the sun for more than 20 minutes. Any skin not covered by sun-protective clothing should be coated at least 15 to 30 minutes before going outdoors.
In addition to sunscreen use, a comprehensive sunscreen program should include avoiding deliberate indoor or outdoor light, seeking shade, wearing protective clothing and limiting exposure to sun during the middle of the day.
On the Net: http://www.aad.org.