What's interesting about this study in Swedish women is that if you look at the results section the high sun exposure group has the highest disposable income and most years of education. Low exposure has the lowest disposable income and least years of education. Probably because for Swedish women high sun exposure means travel which is expensive.
It's hard to say if the study measures sun exposure or the ability to stay healthy with a higher income & better education.
This is the dirty secret about any health study that can be impacted by socioeconomic status: if it can be impacted, it is. More money, fewer problems. 99% of the time.
More likely, there's a optimal amount of sun that you should get to live the longest and Sweden provides less sun than that.
This is especially likely since, as another commenter pointed out, they corrected for wealth factors already!
Stockholm is at 60N, the university that did this study, Lund, is at 55N. If you live further south than that, you might be getting optimal, or even more than optimal, amounts of sun even without sunbathing.
But does it control for family/relative income? One could be poor but could travel and maintain a safety net from their family.
Too many variables to control for imo to abductively say the sun helped. Once you start controlling for enough variables to start teasing out causation, degrees of freedom and the power of the tests become precarious.
Not to mention issues with data dragging/p-hacking: we don’t know if they just tested a bunch of random things and are only reporting the interesting finding.
But regardless, even if we give them the benefit of the doubt regarding p-hacking, this paper has not reached a sufficient level of abduction to convince me of anything. Even if there is a correlation between sunlight and health, this correlation doesn’t deduce the mechanism, meaning I can’t prescribe myself any solution. Is it because going outside and enjoying yourself causes less stress? Then video games would be just as good. Maybe it’s the vitamin D? I could then just supplement. Maybe people who go out more are more connected to family? I could spend time with them inside. One could argue the mechanism is not important, but that ignores that sun damage dramatically increases skin aging and skin cancer risk, and also ignores that I could expose myself to the sun and unintentionally avoid the real mechanism behind the desired effect.
One variable doesn't necessarily overwhelm others. That's why multivariate analysis is needed; but humans introduce SO MANY variables that it's difficult to even enter them all.
The abstract refers only to “sun exposure,” but it really did focus on sunbathing:
> Four predetermined questions were posed regarding sun exposure: (i) How often do you sunbathe during the summertime? (never, 1−14 times, 15−30 times, >30 times); (ii) Do you sunbathe during the winter, such as on vacation to the mountains? (no, 1−3 days, 4−10 days, >10 days); (iii) Do you use tanning beds? (never, 1−3 times per year, 4−10 times per year, >10 times per year); and (iv) Do you go abroad on vacation to swim and sunbathe? (never, once every 1–2 years, once a year, two or more times per year).
"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.
Another factor is the location of the study in Sweden. In summer the typical peak UV index in Sweden is 5 whereas in Australian summers the UV index is often 11+.
New study finds people that follow the least number of studies live the longest.
People who take time to de-stress living longer, seems entirely unsurprising.
People who can take time to de-stress living longer, surprise surprise
This feels to be strongly in the “correlation does not imply causation” bucket. Something like being in the sun means you’re outside and therefore not sedentary fits with our current understanding of health and might balance out the increase in mortality due to skin cancers
The study was on Swedish women. I've heard doctors tell me before that it's more likely to die early from not enough sun then to die from skin cancer(due to too much sun), if you're a Swede.
We don't get much sun up here!
If you live somewhere further south (Stockholm is at 60N, so you probably do), your milage is very likely to vary.