UV doses of young adults.

Since 1986, people have been informed that they get about 80% of their lifetime ultraviolet (UV) dose by the age of 18. This belief originated from the mathematical conclusion that diligent use of sunscreens (sun protection factor 15 or higher) during the first 18 years of life would reduce the lifetime incidence of nonmelanoma skin cancers by 78%. These data were misconstrued to mean that individuals also got about 80% of their lifetime dose of UV by the age of 18 (linear relationship).

Standardized protocols for photocarcinogenesis safety testing.

Solar ultraviolet radiation (UVR) is recognized as a major cause of non-melanoma skin cancer in man. Skin cancer occurs most frequently in the most heavily exposed areas and correlates with degree of outdoor exposure. The incidence of skin cancer is also increased by contact with photosensitizing drugs and chemicals such as psoralens, coal tars and petroleum stocks.

The historical aspects of photocarcinogenesis.

The concept of photocarcinogenesis is of fairly recent duration. Although cancer of the breast is described in the ancient Greek medical literature, skin cancer is not mentioned even as late as the 18th Century. This is most likely due to the poor survival of humans, 80% of people did not live past 40 years, and only 6% lived longer than 60 years.