Preventing excess sun exposure: it is time for a national policy.

Abstract

It is now well established that childhood sun exposure is the primary risk factor for melanoma. The seminal observation linking age at exposure to risk was the finding that the incidence of melanoma increased among people who had migrated from northern latitudes to more equatorial latitudes but only among the immigrants who were children at the time of the migration (1–3). Individuals more than 15 years of age who emigrated from England and Ireland to Australia had substantially reduced risk of melanoma compared with those born in Australia. It has been confirmed that sunburns during childhood and adolescence are associated with an increased risk of melanoma (4). Lifetime exposure to ultraviolet radiation, including that incurred during adulthood, appears to play a major role in nonmelanoma skin cancer (5). To reduce the risk of both melanoma and nonmelanoma skin cancer, reduction of exposure to the sun throughout life is warranted. The article by Autier et al. (6) in this issue of the Journal raises important questions about the use of sunscreen to reduce the risk of skin cancer. Using a rigorous double-blind, randomized, controlled design, the authors observed that participants who received high sun-protection factor (SPF) sunscreen spent more time in the sun compared with those who received lower SPF sunscreen, despite the fact that all participants were blinded to the SPF formulation that they received. This finding may help us interpret previous epidemiologic studies (5) that have suggested that individuals who use sunscreen actually have higher rates of skin cancer than those who do not use sunscreen. It is likely that individuals whose skin type and/or genetic background place them at high risk for skin cancer have a propensity to burn when they are exposed to the sun and they are thus more likely to use sunscreen. The results of this trial add further evidence to the debate regarding recommendations for use of sunscreen. This trial suggests that the use of sunscreen alone will not lead to lower exposure but rather may result in longer time spent in the sun. Furthermore, study participants used only about one quarter the amount of sunscreen that is recommended for adequate coverage. This finding suggests that the increased skin cancer rates found among sunscreen users might also be associated with inadequate use of sunscreen. The results of this study may have a substantial impact on the public’s efforts regarding sun protection, particularly since sunscreen is widely considered by the public to provide adequate sun protection. Sunscreen use is the most common sun protection behavior currently performed in the United States, particularly by children (7). In considering the results of this study, it is important to remember that, until the second half of this century, sun exposure was avoided and at the beach clothing covered the