It has for instance been proposed that certain traits that are closely associated with the phenotype of type 2 diabetes, such as levels of glucose, haemoglobin A1c (HbA1c) and insulin, could be partly responsible for the association between type 2 diabetes and dementia.11 Whether genetic susceptibility to these traits could predict dementia is therefore also an important phenomenon to investigate further. Here, INS is linked to type 2 diabetes mellitus.