https://www.nationalgeographic.com/photo-of-the-day/photo/ul...
Skin cancer from sun exposure wasn't something I think they'd have considered in the USSR.
1. If the children didn't have enough vitamin D, wouldn't a pill be a much cheaper and easier solution?
2. There seem to be other possible reasons for prescribing treatment with ultraviolet light because I seem to recall a case of someone (in England, half a century ago) having that recommended for some kind of skin condition.
Apparently they did that too. [1]
If I were to guess, there was probably a belief that you could be getting some unmeasured health benefits from sunlight that you don't get from a vitamin D supplement.
In the 30s in the US the government mandated that all milk be fortified with vitamin D.
> There seem to be other possible reasons for prescribing treatment with ultraviolet light because I seem to recall a case of someone (in England, half a century ago) having that recommended for some kind of skin condition.
My grandpa was treated with radiation for his eczema as a kid. IIRC, he was blasted with xray radiation. While he lived into his 90s, he had some of the worst skin I've ever seen in my life. That treatment ruined his skin for life. He was actually used in dermatology glossaries for several skin conditions because he basically had them all. I'm sure if you look up various skin conditions you'll probably still see pictures of a patch of my grandpa's skin :).
IDK if the USSR was doing it. Most of the literature I saw was saying it was to combat rickets.
[1] https://doaj.org/article/8ad9233cdeb54973aec8b3b0d84ec88e