On the mechanisms behind type 2 diabetes-induced cognitive deficiencies

There are several risk factors associated with the sporadic forms of Alzheimer’s disease (AD), or late onset Alzheimer’s disease (LOAD). While ageing is a strong factor, it is not, per se, sufficient, as it “only” occurs in a less than a third of the aged population. What then makes that certain old individuals develop this disease? Thanks to genetic and epigenetic studies we now see sporadic AD as the consequence of the interaction between multiple genes (i.e., polygenic) and environmental factors (i.e. complex trait-disease). In this scenario, none of these factors individually (gene mutation/polymorphism or environmental insult) are necessary nor sufficient to cause the disease and the probability of developing LOAD is the consequence of the weighted combination of genetic variants (i.e., polygenic scores) and environmental factors. One well-characterized genetic risk factors for LOAD is the presence of the ApoE4 allele, which increases the risk and advances the age of initiation2. Besides these factors, another risk factor for LOAD is diabetes.