Sun exposure and mortality from melanoma

Conclusions

The comon belief that sunlight causes melanoma and that avoidance is beneficial is addressed in this and associated studies. As with many other biological (and political and economic) systems, oversimplification can lead to incorrect and incomplete beliefs that may in turn lead to counterproductive measures. Although this study does not rule out the advisability of limiting sun exposure, the observations provide some insight into the mechanistic aspects of different melanomas that are further elucidated in the accompanying paper (see next reviewed trial). These authors have hypothesized sun-dependent conversion of 25-hydroxy-D₃ to 1,25-dihydroxy-D₃ in the skin provides the ligand for the cellular vitamin D receptor, resulting in antiproliferative and proapoptotic effects. In addition, sun exposure causes increased “melanization,” a phenomenon that has been associated with increased DNA repair and that may explain the very low incidence of melanoma in people of darkly pigmented races.