Given that two separate teams found evidence for the
same variant in a large number of sick people, «one can be absolutely confident that this
risk allele is real,» says McPherson.
15 In fact, type 2 diabetes (T2D)-- a condition stemming from broken glucose metabolism and insulin signaling — has been identified as an additional
risk factor for developing AD.16, 17 Moreover, the pathological changes that occur in AD in the brain physically resemble those seen in the pancreas and vasculature in T2D.9, 18 Type 2 diabetics who carry ApoE4
alleles are at the greatest
risk for AD, with an even more severe
risk reserved for those treated with exogenous insulin.19 This suggests that either T2D or related features of the metabolic syndrome bring about AD, or that they are separate consequences of the
same underlying cause — and moreover, that insulin is a key factor.