I have been PADI Open Water Scuba certified since 1986. I contracted Diabetes Type 1 in 1973 and have been on insulin shots and, since 1999 the insulin pump. I have logged over 300 dives, both deep and shallow, wreck and wall all without substantial consequence. I manage the risk as oulined in this site:
http://scuba-doc.com/endmet.html
There are a couple of things to note.
1. Be willing to test your blood sugars as directed in the link above. Also make sure your HA1C is between 6% and 9%.
2. Seasickness, if you get this, you will be unable to treat low blood sugars pre and post-dive. Make sure you are willing to ABORT the dive, no matter how much money it may have cost you.
3. Make sure your BUDDY does not have diabetes.
4. Get your doctor to work with a good scuba doctor when getting your release forms signed, my current doctor is a pain in the you know because he is paranoid about lawsuits.
IMHO
Snaggo