The increased sunshine levels in the more equatorial latitudes of Costa Rica, Thailand and the Nepalese Himalayas — all the places where Paul felt fine — may also be factors involved in Paul's remission.
Increased sunlight means you are getting much more vitamin D: high amounts of vitamin D are made when strong sunlight shines on the skin. It is the ultraviolet (UV) component of sunlight that produces vitamin D when this light shines on you.
My PCP went to a conference in Phoenix recently, where the issue of Vit D deficiency was a topic.
He said that the rate of deficiency was the same in Arizona as it was in the Northeast. I was surprised. He said that
heat(direct sunshine) avoidance and sunscreen are thought to be the biggest factors.
I have no idea if this factored in this particular case, just some food for thought.