Newsletter XXI - UV Protection and Age
Skin cancers are the most commonly diagnosed of all cancers and one of the most common sun-related disorders. Unfortunately, one myth has permeated our understanding of how this disease begins and has been used publicly to promote the use of sunscreen for skin cancer prevention. Based on a research paper published in 1986, the myth is that we receive 80% of our lifetime ultraviolet radiation (UV) dose by the age of 18. This is completely incorrect. While it was beneficial that this misconception taught us to use sunscreen and apply it to our children's skin, it is equally beneficial to understand how UV exposure actually occurs, so we know to protect ourselves regardless of age.
The myth was based on a complex mathematical model that predicted diligent sunscreen use during the first 18 years of life could reduce the lifetime incidence of skin cancers by 78%. Unfortunately, many people assumed this meant individuals got 78% to 80% of their UV exposure during their first 18 years. Wrong!
Dianne Godar from the Food and Drug Administration was the lead author of the 1986 paper. In 2003, in an effort to help correct the widely quoted misunderstanding of her group's original work, she and several associates wrote another paper, reporting that "Individuals only get about 23% of their lifetime UV dose by the age of 18. They get about 46% by the age of 40, and 74% by the age of 59, [then 100%] assuming they live up to the age of 78."1 As you can see, UV protection is vital at all ages.
In this second paper, Godar and colleagues commented on some behaviors that had not been part of the original calculations. For example, electronic games and computers may now motivate young adults to stay indoors during daylight hours more than ever before. This could decrease the incidence of skin cancers that are caused by cumulative UV exposure.
Godar and associates also found that women get lower lifetime UV doses than men and get fairly consistent doses of UV throughout their lives, whereas men over the age of 40 actually increase their outdoor activities and their exposure to UV. In general, however, the average American gets almost 80% of his or her lifetime UV dose by the age of 60, assuming he or she lives to the age of 78.
What does this mean for you? Sun protection is important at every age. The exposure myth may have led you to believe it didn't matter if you used sun protection after the age of 18 because you weren't getting as much UV. This is absolutely wrong. You should always be SunAWARE and protect yourself no matter what your age.
1. Godar, D.E., Urbach, F., Gasparro F.P., and van der Leun, J.C. "UV Doses of Young Adults." Photochemistry and Photobiology, 2003, 77 (4): 453?57.