Coeliac Disease is another auto-immune disease and so T1s could be considered to be more susceptible. Like T1, full blown Coeliac disease can be catostrophic, as the villi (like the beta cells in T1s) are totally destroyed.
Blood tests only pick up the anti-bodies produced by the effects of the disease and are notoriously un-reliable.
The only reliable test is to have a camera passed down through your stomach to take a biopsy
In the UK we have been very poor at diagnosing this disease, in the USA my sister was diagnosed quickly and had excellent follow up treatment and investigations to ensure that no other damage had been caused.
In theory like T1 it should have a greater prevalence in young people but globally more older patients are now being diagnosed.
This makes me believe that there is in fact nuch more to this than meets the eye. There is almost certainly a wider level of wheat/gluten intolerance (including IBS?) all the way up to full coeliac disease and until someone investigates the full spectrum of these diseases we will not know the answer.
But I would certainly suspect that the intensive breeding of wheat (even their possible contamination by GM varieties) has led to many people having an intollerance or even developing full blown coeliac disease.
After my sister was diagnosed with coeliac disease in the USA and I found out I was T2 I had the blood test (twice, as the first test went wrong?) but was declared all clear. However I know that I feel pretty awful for a few days after eating any wheat based products, so along with the lowering of carbs I now try to eliminate wheat gluten too - but I really do believe we need some thorough independant research into this.