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by streaming 679 days ago
It's always healthy to be skeptical, but we know that on the whole, sunlight is healthy for humans. People who get more sun exposure live longer (even though they have a higher incidence of melanoma). We know that it's more than just the Vitamin D that is produce when our skin is exposed to sun. There are numerous studies showing the benefits of sunshine, so the next question is "what is the mechanism for sunshine to improve human health?". One theory is that it stimulates the production of intra-cellular melatonin. A seminal paper on this topic is "Melatonin and the Optics of the Human Body".... http://sininenankka.dy.fi/~sami/kielletyt_uutiset/melatonin_...
2 comments

Heliotherapy is an ancient practice!
I don't think it's so easy

> People who get more sun exposure live longer

Yes, but that's not a causation yet, that's a correlation. Most likely healthy people go outside more than sick people and thus get more sun exposure.

> Most likely healthy people go outside more than sick people and thus get more sun exposure

Such a lazy critique.

Here's the actual study: https://onlinelibrary.wiley.com/doi/10.1111/joim.12251

Number of subjects: 39,973

Follow up period: 20 years

Some factors controlled for: smoking, history of antidiabetic meds, history of CVD meds, weight/height/BMI, level of exercise, income, alcohol consumption, N pregnancies.

I think these factors pretty well correlate with "health" (however you'd measure actually that).

That's what the authors say:

> Despite having adjusted for several potential confounders, the major shortcoming of this study is the inability to distinguish between the consequences of an unhealthy lifestyle and of avoidance of sun exposure.

Take depression for example. None of the factors you mentioned would control for it and depression is often not diagnosed, especially early on.

And I'd guess smokers go outside more than non-smokers.
Surprise, the study designers did happen to also think to control for smoking.
Agreed, and you already addressed this with your sibling comment. I just thought it was an amusing counterpoint to "healthy people go outside more than sick people".