How do they know the causal link? Can it be that people who stay up late sleep less and this causes issues, and there being light is only a consequence of staying up late?
> These relationships were robust after adjusting for established risk factors for cardiovascular health, including physical activity, smoking, alcohol, diet, sleep duration, socioeconomic status, and polygenic risk.
Correlation is not the same as causation. The research indicates a correlation. Assuming causation is a classical mistake with any research.
In any case, light sensitivity and sleep patterns are well linked. If you live far away from the equator, you are dealing with pretty short nights half of the year. I lived in Helsinki for a while. That can really mess up your sleep though some people manage to adapt. There's a reason coffee is popular in places like
I currently live in Berlin. I sleep about 2-3 hours less in the summer than in the winter.
Somehow that works for me. But it's really annoying to be wide awake at 6 when you've set your alarm for 8. I'm literally typing this on my laptop early morning on a Sunday. But it's light very early this time of year.
I've experimented with wearing sleep masks. They really work. But I find them slightly uncomfortable. What works better is just doing sane things like trying to live healthy. Less alcohol, more sport. Etc. Work stress can cause all sorts of issues with that.
> I sleep about 2-3 hours less in the summer than in the winter.
That's not OK, I don't know a single person affected so (live in cca same latitude as Berlin). Have you tried some radical solutions like good window blinds or similar sun blocking mechanisms? I don't mean some cheap crap that still lets strips of light through, I mean full block. Of course if then some chopper or ambulance wakes you up regardless it doesn't matter.
I know several people that complain about the exact same thing. You just naturally wake up a lot earlier when it's bright and sunny around 4-5am. Most of nature does the same thing. All the birds get crazy active early morning. The expression "up with the lark" comes from that notion. I have light blocking curtains and they do help a little. But my bedroom faces east and I get the full blast of the Sun in the morning. Somehow this is fine and does not affect my energy levels too much.
These days I don't drink alcohol any more, which has done wonders for my sleep quality. Quitting alcohol works better than almost anything else you can do. Long summer nights of drinking beer in the park (which is one of the perks that Berlin has) are not that great for this. But still, I easily sleep to 9am in the winter and in the summer I usually am awake a lot earlier. I typically stay in bet for a bit.
I take vitamin D now but wasn't aware at the time. I never used the light therapy lamp but I had plenty of Italian colleagues that used one. The first time I encountered one of these things, I thought Apple had released some kind of new imac that I hadn't heard off yet. Until somebody explained to me that "no, that's a Philips bright light". Basically you wear some sun goggles and stare at it for fifteen minutes or so while you are blasted with what is indeed very bright.
The dark/light situation never affected me that much. But I could definitely see it in people around me. People from further south have a hard time dealing with darkness. Insomnia is something to guard for.
The Finnish are famously one of the most happy people around. But they also have relatively high suicide rates that spike in spring when after a miserably long winter, the availability of light pushes some people over the edge. As I used to morbidly joke, "Finland is so happy because all the unhappy people keep killing themselves thus removing themselves from these surveils". The Finnish love dark humor like that. This got a chuckle out some of them.
It's true that depression and suicides peak in the spring (Reverse Seasonal Affective Disorder), but that's the case all over the world. Finland is far from the worst in suicide statistics: within Europe, the unfortunate outliers are Slovenia and Lithuania, followed by Hungary. The situation is worse than in Finland also in Belgium, Croatia and Estonia (plus the US). France and Latvia have the same numbers as Finland. Only marginally better are Serbia, Poland, Norway, Sweden, Austria, Czechia and Switzerland.
Meanwhile, the fortunate outliers are more in the south: Cyprus, Greece, Liechtenstein, Türkiye, Italy and Luxembourg.
"Correlation is not causation!" is one of the sillier things that people say when a study comes out with meaningful, interesting data. If nobody ever finds correlations in the first place, then it won't be possible to figure out causation - and we certainly do want to eventually find more causation for things like heart attacks, don't we?
I see it constantly when a study comes out all of these statistics students come out of the wood work and say "Correlation doesn't mean causation" without any other thought.
The study clearly claims only a correlation and absolutely, correlations help focus attention to try and find causal links in the future.
