Alcohol, high blood glucose, and not just from sugar, some nice fresh sourdough bread kicked it off for me once. High altitude can do it, and stress can absolutely kick it off as well. It started when I was late for a plane one day, and when I lost my daughter.

Also, if I had a higher carb day that did not kick it off, sometimes when I’ve gone running or weight lifting the
next day it will kick off. I’m guessing that goes back to blood glucose. I even wear a continuous globose monitor these days to keep an eye on that.

Everyone is different, but those are all pretty much standard triggers.