FRIDAY, Jan. 24, 2003 (HealthDayNews) -- Skiers, take note: The sun's ultraviolet A and B rays can be as strong on a mountaintop in winter as they are at the beach in summer.
This makes the risk of sunburn and the potential threat of skin cancer as serious a concern for skiers as it is for swimmers, a new study says.
The study, published in the current issue of The Archives of Dermatology, is the first to scientifically validate the level of winter sun exposure in those who ski -- and the results surprised even the researchers.
"We always knew that the winter sun had the potential to cause sunburn, but we were surprised to see just how powerful those rays are -- and how quickly and easily you can get burned on a mountaintop," says study author Dr. Darrell Rigel, a professor of dermatology at New York University School of Medicine.
According to Rigel's study, spending one hour on the slopes at lower elevations at Vail, Colo., in December is equal in sun exposure to spending one hour on the beach in New York in June.
"And the very top of the mountains in Vail are equal in sun exposure to being in the Caribbean Islands in the summer," Rigel adds.
Just in case you think the conditions were unique to Colorado, Rigel says similar risks are likely on most ski slopes, from the trails in Vermont and New Hampshire to the mountains of Switzerland and Austria.
The research was accomplished with a new measuring device called a digital dosimeter. A small, portable unit that can be worn on the upper arm or the wrist, it uses a sophisticated computer chip to register both UVA and UVB rays, the burning rays of the sun.
However, it wasn't just the strength of the sun's rays that researchers considered. They also factored in the effects of the altitude and the reflection of sun off the snow, as well as air quality, all of which figured prominently into the final risk profile, Rigel says.
"For every 1,000 feet of elevation, UV exposure increases between 4 and 8 percent, so the higher you go the greater the exposure, and ultimately the greater your risk of sunburn," he says.
The reflection of the snow, he says, accounted for some 40 percent of the UV exposure rate, while the clean mountain air also served to increase the risk of sunburn.
"That's because the rays can reach the skin that much easier when they aren't being blocked by pollutants in the environment," Rigel says.
For dermatologist Dr. Walter Urbanek, the findings aren't surprising. Still, they make an important contribution to the bank of knowledge on skin cancer risk factors, he says.
"This study scientifically validated what we have intuitively known for a long time -- that when it comes to the risk of sunburn and the risk of skin cancer, the winter sun is as dangerous as the summer sun," says Urbanek, director of dermatology at Staten Island University Hospital in New York City.
In 2002, nearly 88,000 Americans were diagnosed with melanoma, the potentially deadly form of skin cancer strongly tied to sun exposure and sunburn, particularly burns before the age of 18. The face and neck are the places most likely affected -- areas that are often exposed while skiing.
To prove their theory about winter sun, Rigel and his colleagues recruited 10 professional ski instructors. Each agreed to wear a disometer on the outside of an upper or lower arm, or a wrist, every day from Nov. 27, 2000, through Dec. 22, 2000.
The disometers were set to register the UV ratings three times in five minutes, at varying intervals throughout the day. At the end of each day, the machines retained the three highest readings.
The information was then downloaded into a computer, which analyzed the data to obtain an average hourly sun exposure rate. Ultimately, cumulative exposure rates were established.
In the most extreme cases involving instructors with very fair skin, exposure rates were two and half times the normal summer sun at the beach, according to the study.
To guard against the skin damage caused by sun exposure -- winter or summer -- Rigel suggests a sunscreen with a sun protection factor (SPF) of 30.
"Don't leave home without it -- winter or summer," he says.
More information
For more on the risk factors for skin cancer, visit The Skin Cancer Foundation or the U.S. Centers for Disease Control and Prevention. To learn more about the benefits of sunscreen, check this CDC site.
