INS and type 1 diabetes mellitus: However, those with later onset type 1 diabetes had a modestly lower T1DGRS (0.268 vs 0.279 [expected type 2 diabetes population median 0.231 [8]]), higher islet autoantibody prevalence (78% vs 62%, at 13 vs 26 years duration) and were more likely to be treated as, and identify as having, type 2 diabetes (oral glucose-lowering agent use, 15% vs 5%; insulin at diagnosis, 62% vs 96%; self-reported type 2 diabetes 20% vs 0%).