YES! It can cause diabetes! It is listed as glucose intolerance in the side effects. I went though 8 months of #@!& on nuvaring. I went to the doc because I wad exhausted all of the time, fuzzy brained, and starting to loose my hair. When I asked if it could be the birth control, my question was dismissed. They tried to put me on all of this medication for slightly elevated blood sugar. I refused. I decided to go off the nuvaring, which I was on only for acne. I felt incredibly better after only a week and after 2 weeks I felt like super woman. I discovered many other issues stemming from nuvaring including shortness of breath and horrible completely out of character mood swings.
OOPs. Meant to say found nothing on triglycerides causing diabetes, not "diabetes causing elevated triglycerides."
This article links uncontrolled diabetes causing elevated triglycerides.
http://www.diabeteshealth.com/read/2005/06/01/4294/type-2-diabetes-and-triglycerides/
And this one
http://www.diabetesselfmanagement.com/blog/Amy_Campbell/Troublesome_Triglycerides_Part_1
I searched and found nothing on diabetes causing elevated triglycerides. Sorry, I can't assist you with Nuvaring nor birth control for they are beyond my diabetes scope. Hopefully someone will come along that can answer these questions.