As there was other reasons for getting diabetes other than autoimmune (type 1) and insulin resistance (type 2) scientist used the grouping type 3. as research was looking Alzheimers and insulin in brain protein the scientist used group type 3, as other research into different types of diabetes were also using grouping type 3 it was easier to divide type 3 into sub groups
A,B.C,D,E,F,G
Pancreatic damage due to illness or injury is grouped in type3C, so no we don't have Alzheimers or at any greater risk of Alzheimer's than anyone else.
Although having pancreatic damage due to illness or injury doesn't necessarily make you type 3c, you could still be type 1 or 2 as both Alpha and Beta Cells have to be destroyed for a type 3c diagnosis.