The disease may have multiple causes. I wouldn't at all be surprised if some other area of health decline gives rise to the disease state. A number of investigators are looking into vascular health, for instance.
Here's an article I posted a while back that implicates liver health and was able to mechanistically induce the disease in rat models:
Here's an article I posted a while back that implicates liver health and was able to mechanistically induce the disease in rat models:
https://news.ycombinator.com/item?id=29393937