I've been suffering from these blasted things for 18 years, and have similarly noted the same sorts of correlations. My best efforts: cutting out gum; cutting out sharp foods; cutting out acidic foods; taking vitamins B-12 and C, L-lysine, and zinc; switching toothpastes and brushing techniques. I regret not recording my history of occurrences, but I perceive things are improving. At the very least, it's safe to say the cause of canker sores is multi-factorial.

Sorry, I'm rambling. No one in my life can relate, so I'll take any chance to talk about it.