Again, I begin with an apology for the long delay in your getting an answer. We're all volunteers here and it seems that busy lives interfered with answering questions the past coupla days.
We are also not physicians, so do talk carefully with your pediatrician about your concerns.
I read the excerpt from the JAMA article that you cited in your question. I also noted the JAMA reminder/caution that food does not cause Type 1 diabetes. Type 1 diabetes is an autoimmune disease. This study and others looked at the impact of specific foods/timing of introduction in at-risk children.
Please know that Type 2 is a completely different disease than Type 1. Type 1 is autoimmune, and researchers are striving to find out what triggers (or doesn't) trigger the disease. Type 2 has completely different origins.
It seems to me that you have been working very closely with your pediatrician. General recommendations for when to inroduce certain foods are just that ... general recommendations. Your child needed something different due to his unique situation.
My advice is to love your child, care for him, continue workign with his pediatrician, and don't worry about the many illnesses that might, perhaps, maybe, someday show up -- or not. It is normal to worry about our children and to do all in our power to protect them. It sounds to me that you're doing that just fine :-)
Diabetes is a chronic disorder.The first type of diabetes is sometimes called insulin-dependent
diabetes mellitus (IDDM) or juvenile-onset diabetes. Diabetes results from a shortage of insulin.