Not sure where the article is at but there seems to be some types of infections that can spread if one is working with very ill people, and they can lay dormant in an otherwise healthy person or heavy metals and such can eventually clogg the arteries. In the case of Edgar Cayce I think he was healing many people before he died and he might have contracted something during his healing work or elsewhere for that matters that gave him stroke later on, or perhaps he was more needed elsewhere and it was just time for him to die. People are dying all around the world so why would the enlightened be an exception? If you look at some physical healers like Hulda Clark for example their work is actually focused on the physical body rather than the spiritual body, and she also heals many people around the world just as Edgar Cayce but she will most definately still die one day anyways. How old can the physical body get is perhaps another question.