Some studies found no association (Arvanitakis et al., 2006; Thambisetty et al., 2013); while, interestingly, others suggest that hyperglycemia, impaired insulin secretion, glucose intolerance and insulin resistance are all associated with increased risk of AD (Luchsinger et al., 2004; Ronnemaa et al., 2008; Crane et al., 2013a). Here, INS is linked to Alzheimer disease.