I did[1], and would be curious if anyone is familiar with the underlying study. How did they attempt to control for other factors?

Also do you have to get a sunburn for sun damage to increase the risk of skin cancers? My understanding was accumulated sun exposure was the issue.

[1] Lindqvist tracked the sunbathing habits of nearly 30,000 women in Sweden over 20 years. Originally, he was studying blood clots, which he found occurred less frequently in women who spent more time in the sun—and less frequently during the summer... decided to look at overall mortality rates, and the results were shocking. Over the 20 years of the study, sun avoiders were twice as likely to die as sun worshippers.

What I got from this is if we mandate the hospitals open their rooms to the sun, the new correlation will cause people to avoid the sunlight because "it leads to more deaths"

That logic is extremely broken. People who spend more time outside do so because of more physical activity. The sun exposure is a side effect. Drawing the conclusion that sun exposure is therefore safe is just totally bonkers.

Sigh.

Correlation != causation

It could be that people that spend more time in the sun are busy getting exercise. Which lowers blood pressure.

It could be that people that spend a lot of time in the sun know that they have skin damage, and are more likely to detect melanomas due to more frequent checks of their damaged skin.

Summary: More sun exposure may or may not lead to lower risk of death on two fronts. It seems far more likely that getting exercise and frequent melanoma checks lead to better outcomes, and both of those are correlated with being in the sun, but by no means necessary to the outcome.

I read the article and it conjectures a bunch of stuff but fails to prove it or link relevant studies.

So consider then: we just did a round of "gloves are contaminating basically all micro plastics research" - it might be worthwhile to be slightly skeptical of a suspiciously anti-sunscreen adjacent narrative (coz "sunscreen might be bad for you" is in the article too).

And we should absolutely be suspicious of narratives which have the benefit of confirming someone should do what they already wanted to do: nobody likes putting on sunscreen.

And how strange the conclusion is mostly "you don't need sunscreen" versus "use a lower SPF".

It would be useful to have an option to change the time of day, rather than always using the current time; e.g. for planning at night what to do tomorrow.

Denver, CO, USA resident here -- this looks _super_ useful and I'm likely to start using it heavily. Our weather here is usually very outside-encouraging (if getting hotter over the years) and our UV is _ridiculous_; I see the index hit 11 and 12 with some regularity. Thanks for the link!

Looks like the weather might be a bit off, I imagine from your upstream provider. In Indianapolis, all stats look correct except it says we have thunderstorms. Couldn't be a clearer day and nothing on the radar.

This is awesome thank you for making this!

I often embarrass my daughter when she has some new friend over. If the topic comes up, I give a demonstration. I'm 62 and I've never tried to get a tan and work indoors, and I haven't had a serious sunburn in close to 40 years. On the other hand, I lived spent the last 20 years in Austin, TX. I mow the yard and I ride a bike and in the summer months I put on sunblock before doing the bike rides an sometimes mowing.

The exposed parts of my arms look like I'm 62 -- freckles, some age spots, the skin has lost a lot of elasticity. But then I roll up my T-shirt sleeve to expose my shoulder and my skin is like it was when I was 25: not just pale, but no freckles, no age spots, still supple.

Pro golfers look a good 10-20 years older than their real age sometimes fwiw. In contrast to most other pro athletes in indoor disciplines who generally look better than their age. There's also examples of truckers who spent most of their career with the window rolled down and you can tell straight up what side of the road they drove on.

Who cares about your skin looking a little older when it prevents cardiovascular related deaths??

I'd rather look old than be one of those lunatics who goes for a summer walk in a longsleeve shirt, gloves, and a hat with built-in veil (a pretty common sight in the Bay Area)

I've not heard that grey hair is sun damage.

Do you have any sources for that?

The article explains that it is much safer than not getting UVB. Nothing in this universe is completely safe, but the evidence is that getting UVB is bar far safer than not getting it

Moderation is good, just don't overdo it...

Extreme tension leads to breakage. Something something in buddhism about not trying to put too much tension in a bow or it'll break.

Also known as the middle way.

Moderation is a great philosophy.

The title is inadvertently correct only because modern margarine is healthier than alternatives such as butter.

Australia is kind of an exception. You’ve got a super outdoor culture, a bunch of fair-skinned people, thin ozone, and very clear skies.

Yeah, lack of Vitamin D may or may not be a problem (well, obviously in extreme cases it leads to rickets, but that's rare). But skin cancer unquestionably is a problem, and not infrequently a deadly one. Pick your battles.

The article doesn't make really controlled findings. There's an argument to be made that the increase to diseases isn't purely lack of vitamin D but lack of exercise.

Our ancestors got lots of Vit D but they also got lots of exercise while absorbing the sun.

I still don't think it's going to be wise to go out and just bake in the high UV of early afternoons but rather it's important to go outside early to mid morning or late afternoon and absorb some sun without copious amounts of sunblock.

I have heard that some Asian or European sunscreens have some UV blockers that are much more stable than the ones that are mainly used in sunscreens available in the USA. So if you’re using one of these, the need to reapply isn’t as much of a concern. The only thing is that they aren’t FDA approved.

Some examples I have heard of are “ethylhexyl triazone”, “diethylamino hydroxybenzoyl hexyl benzoate”, and “bemotrizinol”.

EDIT: The last chemical on my list was actually approved by the FDA this month (June 2026).

Sunscreen isn't a 100% block, though. In fact it's advertised by what proportion of the UV it blocks. And in general it's far more common to have too much sun exposure than too little, and in the areas where people have too little, it's not exactly the norm to wear sunscreen every time you step outside.

I don't know of anyone using sunscreen from the moment they wake up until they go to sleep. Guaranteed that even the best user will still receive a healthy amount of UV even if they refresh every few hours. As far as I'm concerned sunscreen is a 10am-5pm endeavor, not needed before or after

Yeah, but it is better than margarine?

A bit unclear - it says

> Weller’s largest study yet is due to be published later in 2019

But in the header, it also says

> Updated May 31, 2024

I'd still love to know whether there has been further research in the meantime.