It's completely pointless for the general public, the media, or anyone else to take any particular advice or truth from any single medical study. Even if it's a good study, and you know how to evaluate if its good, even if it's highly plausible and has a mechanism of action it's almost never the case that a single study will be likely to make a strong enough case to jump to a conclusion or even consider a conclusion highly likely.
Before anyone gets too excited about another opportunity to say the line about correlation:<p><i>> We acknowledge several major limitations of this study. First, it is not possible to differentiate between active sun exposure habits and a healthy lifestyle, and secondly, the results are of an observational nature; therefore, a causal link cannot be proven.</i>
I've read in "Lies My Doctor Told Me" by the MD Ken Berry that there isn't a single paper that shows that sun exposure is bad.<p>In particular the current consensus is that Vitamin D is essential to health and so this is considering that sun is avoided but replaced by pills, as the protective role of vitamin D is well-proven. But there are many other health benefits that are triggered by sun exposure (the skin metabolism activates and it goes down to influence gene expression).<p>So I've looked a few articles (at least 7, including some reviewing existing research), and sure enough there wasn't a single paper that actually showing that sun exposure is bad. They all relied on showing on something related to sunlight, most of the time that suntanning with artificial UV beds is really bad. But there it lacks a convincing argument that this transfers to 'the real product', as this is the equivalent of saying that carrots are good/bad for people based on some people ingesting large quantities of carotene in pills. And we know from diet that these kinds of arguments do break down when extrapolating only part of one molecule to a whole, natural product (eggs are a famous example).<p>If somebody has done more research on this please elaborate, I haven't spent too much time because the research seemed in all cases fairly low quality (questionnaires?) and a lot contained confusing arguments (it's not always clear how dark-skinned the individuals are, or how removed from their natural habitat they are, like some Swedish in Australia or Kenyan in the UK, although some do make an effort in that regard).
I haven't delved deeply into the papers here. I'm not a doctor. But have seen in a few places that there is a correlation between latitude and all source mortality. Maybe it isn't just 'people that go outside tend to have a healthy lifestyle and that is why their mortality is lower'. A great Ted Talk on this (now a few years old) can be found here: <a href="https://www.ted.com/talks/richard_weller_could_the_sun_be_good_for_your_heart" rel="nofollow">https://www.ted.com/talks/richard_weller_could_the_sun_be_go...</a>
It's possible that sick weak people are just too tired to want to go outside. In which case it's ill health that causes less sun exposure not the reverse.
Surprised no one is mentioning vitamin D. As I understood it, sun exposure is one of the few ways the body is supplied with this vitamin in a usable form.<p>Vitamin D is essential for the immune system so a correlation between a lack of sun exposure and ill-health seems almost so obvious it's a wonder it needs studying. What would be useful is the exact parameters around sun exposure/vit D metabolism.
Avoidance of sun exposure is mostly connected to more time spent indoors, where the ventilation is lower with higher CO2 buildup, viral exposure, and indoor pollution (mostly VOCs, but also Ozone, and also particulate and NO2 pollution (for gas stoves) from kitchens, etc.). However, outdoor time would have slightly more exposure to vehicular pollution, but likely less to nanoparticles in the case of gas stove usage (<a href="https://www.earth.com/news/gas-stoves-release-more-harmful-nanoparticles-than-vehicle-exhaust/" rel="nofollow">https://www.earth.com/news/gas-stoves-release-more-harmful-n...</a>).
I may be wrong, but I understand vitamin D2 <i>is</i> a vitamin, but "vitamin D3" is in fact a hormone.<p>A vitamin is a building block, which by itself does nothing; a hormone is a directive, which instructs the body to <i>do</i> something - adrenaline, for example.<p>Vitamin D2 is a precursor / building block for the hormone D3.
So, outdoorsy people live longer because of the other health benefits of outdoorsy lifestyle, but are risking more skin cancer? But the risk of skin cancer isn't enough to outweigh the benefits?
Given human instincts are so strong for getting a bit of sun you'd think there must be evolutionary advantage for doing so. Sunbathing, flying to different countries to get sun, the preference for sun tanned skin to pasty, and the whole difference in appearance between black people and whites seems to be an evolutionary response to letting more light in.<p>Presumably because we need the sun to make vitamin D.
I have one of the classic severe photodermatoses and, well, tough luck for me, I guess. I must take some fairly annoying measures if I wish to avoid pain and disfigurement.<p>As to the Vitamin D angle, the more I look into it, the more I see that it is a balancing act, and you need other supplements in a particular ratio for it to be more effective.
It should be obvious that the linear no-threshold model of radiation danger is so weak that other findings are possible. After all, the human body has some repair mechanisms. Vitamin D is just the most well-known positive effect of sunlight.
Is there a correlation vs causation error here? Diet and exercise were not controlled.<p>Asian culture avoids sun exposure and sometimes exercise yet are healthier than their Western counterparts who have an unhealthy diet high in fats and sugar in addition to a sedentary lifestyle.
Reading this paper made me cringe so hard... You can't just frame it like it's sun exposure that leads to low mortality.<p>Or that sentence: "Lack of sun exposure is just as bad as smoking."<p>Do you even hear yourself? Have you taken a statistics course before? How did this even get published?<p>There are 99999999 other reasons that contributed to mortality. Sun exposure is definitely not one of them.<p>Exercise and nutrition are the leading factors, period. Who funded this shit