An analysis of cumulative lifetime solar ultraviolet radiation exposure and the benefits of daily sun protection.

Cumulative exposure to ultraviolet radiation (UVR) increases the risk of developing skin cancer, particularly squamous cell carcinoma and basal cell carcinoma. Thus, the need for protection from the sun is widely advocated, but consumers generally associate such protection with the occasional extreme exposure and tend to ignore the risk of long-term exposure. In fact, a sun exposure model predicts that over a lifetime, a person will receive tens of thousands of minimal erythema doses worth of UVR through normal, daily, incidental exposure. The cumulative effect of casual sun exposure over the years underscores the need for everyday basic UVR protection in which even low level (SPF 4-10) sunscreens are shown to offer significant benefit. Analysis shows that daily protection can reduce lifetime exposure by 50% or more.