"Fewer non-cancer deaths" is about what I expected: getting more sun gets you more vitamin D (especially important if you live closer to the poles than to the e

"Fewer non-cancer deaths" is about what I expected: getting more sun gets you more vitamin D (especially important if you live closer to the poles than to the equator, and the study was done in Sweden), but getting too much sun increases your risk of skin cancer. Since vitamin D is an important part of the body's immune system, you're less likely to catch various diseases (or, more accurately, more likely to fight them off effectively before feeling sick) if you have enough vitamin D. I once watched a video of a medical guy giving a lecture on why people should take vitamin D supplements (he was from Minnesota, which is quite far north of the equator). He had a memorable line, "There's no such thing as flu season, there's only vitamin-D deficiency season." In the summer, he said, Minnesotans who work outside actually get enough vitamin D from skin exposed to sunlight. But in the winter, pretty much nobody in Minnesota gets enough sunlight on their skin: even if the sun is shining that day, everyone is bundled up in warm clothing! Also, the darker your skin is, the more sun exposure you need to get enough vitamin D. So if an African and a European get the same amount of sunlight, the European's body will produce more vitamin D from it, because the African's skin has a lot more melanin. So dark-skinned people are more likely to need vitamin D supplements (whereas light-skinned people such as me are more likely to get skin cancer; there are pros and cons to having more or less melanin). Most people, unless they live in the tropics, would probably benefit from taking vitamin D supplements during the winter. And all year long if you work indoors.