Oh yes, I have tried many things over the years. I have been told that it is systemic. When it comes to a healthy diet and proper nutrients, I've been all about that, since I realized a long time ago that it is one of the best ways to manage my AS.
Here is another odd feature of my systemic disorder. I had a tremendous amount of extra bone growth throughout my body during my most severe flare period at age 30. I used to have a cute gap between my top two front teeth, which closed due to all of the bone growth just above and to each side of them. This is a stock photo, NOT me. http://www.istockphoto.com/stock-photo-11670592-buccal-exostosis.php
Then, in 2009, I had a CT scan of my chest and learned that I have a lot of new bone growth bilaterally off of my first ribs.
It's all just pure weirdness. Not much surprises me anymore.