Americans have been told for decades by dermatologists and public health experts to avoid the sun as much as possible, to decrease the risk of melanoma, the deadliest kind of skin cancer. As usual with such “received wisdom,” however, the story may not be so clear-cut. Recent research has questioned the seemingly dogmatic connection between saturated fat intake and cardiovascular disease. Now, a new study from Sweden finds that more sun exposure actually decreases the risk of death.
Researchers followed a group of of nearly 30,000 Swedish women over a 20-year period. Those with the highest level of sun exposure had a decreased risk of death from cardiovascular disease and other non-cancer chronic diseases. On average, sun exposure led to an increase of up to 2.1 years of life expectancy. On the opposite side of the coin, avoiding sun exposure was similar to smoking in its magnitude of risk for death from those chronic diseases.
Increased sun exposure did indeed lead to more skin cancer; however, those cancers tended to have a better prognosis. So on balance, the decreased risk of other diseases outweighed the increased cancer risk.
One big question remains unanswered: are these benefits due to vitamin D? We know that the body’s own vitamin D production increases with more sun exposure, and that low vitamin D levels are associated with risk of chronic diseases. However, the jury is still out as to whether or not vitamin D supplementation by itself improves cardiovascular outcomes. For now, it looks like the UV exposure from the sun is the best way to go.
So, should we all sunbathe for hours per day? One major caveat from this study is that Sweden, due to its northern latitutde, gets much less UV exposure than the U.S. Also, this study looked only at women. The best approach would seem to be moderation: 15-30 minutes of sun exposure about three times per week is a good goal to shoot for.
Lindqvist PG et al. Avoidance of sun exposure as a risk factor for major causes of death: a competing risk analysis of the Melanoma in Southern Sweden cohort. J Intern Med. Published online March 16, 2016.