|Slip on a shirt, slop on sunscreen, slap on a hat and wrap on shades.|
Getting lots of UV radiation causes skin damage and ages skin. A higher mean UV index has also been associated with increased incidence of melanoma in non-Hispanic whites. A prospective study of UV exposure and cancer incidence also confirms a higher incidence of melanoma in those receiving higher UV exposure. This same study however found a decreased risk of non-Hodgkin's Lymphoma and colon cancer with increasing UV exposure. The study also found significant protection from thyroid, pancreatic and squamous cell lung cancer at intermediate UV exposure levels. Over nine years this study found that UV exposure was inversely correlated to total cancer incidence. The authors hypothesize that the protective effect is due to vitamin D production that occurs in human skin under exposure to sunlight. Is it surprising that the benefits of sun exposure aren't nearly as well known as the risks? I clearly have not done a thorough literature search however there doesn't seem to be much information on UV exposure and total cancer risk. The benefits of UV exposure are possibly less established and have an unconfirmed mechanism which may contribute to the lack of publicity. Also various authorities on skin cancer encourage acquisition of vitamin D through dietary sources.