Thank you for your commen, @procrastilearner!

I have not heard that vitamin D is an issue here. This disease is complex and I can imagine it playing a role. But the causes are not known.

I will check out your guide and see if I can find something helpful! Thank you for the suggestion.

The image sources are in the "Sources" section, including author name and link to license. I can post the links under the pictures in addition to the sources section if that is better.

Thank you for your upvote and help!!