The Winding Path Towards an Inverse Relationship Between Sun Exposure and All-cause Mortality

For a long time, skin cancer has been known to be related to extensive UV exposure. New emerging data have, however, shown low UV exposure/low vitamin D levels to be related to increased mortality rate due to skin cancer. In addition, low sun exposure habits in regions of low solar intensity have been shown to be a major risk factor for all-cause mortality in the same range as that for smoking. This is mainly due to lower all-cause mortality due to cardiovascular disease (CVD) and non-CVD/non-cancer disease among women with active sun exposure. Women with active sun exposure habits were estimated to have a 1- to 2-year longer life-expectancy during the Melanoma in Southern Sweden study interval. These findings are in line with those to be expected from an evolutionary perspective and research findings, but in opposition to present guidelines and recommendations.