I was curious about your point about normal diet and have just looked it up. According to tables 1 and 2 in this article [0], it may be hard for some people to get enough (RDA) iodine from normal, not fortified foods.

0. https://ods.od.nih.gov/factsheets/Iodine-HealthProfessional/

People have been struggling to get enough iodine for a hundred+ years. That’s why it’s added to salt. This isn’t a 21st century problem.

Isn't that what the whole article is about?

But the point is that Switzerland's environment is especially poor in iodine hence the specific health problems it used to have, and which were much less serious in neighbouring countries.

While the cases were high in switzerland, they were not unique.

Link to an academic article discussing how the USA is now in the dangerzone of iodine deficiency.

https://link.springer.com/article/10.1007/s12011-018-1606-5#....

Of course they were not unique. I must say I don't get how the replies in this thread relate to my comments...

Definitely if they live in an inland region. Seaweed and fish have abundant iodine.