After the discovery of the APOE gene and knowledge of its genetic variants, several studies have demonstrated the association between the APOE polymorphisms and chronic conditions, such as Alzheimer's disease[15], age-related cognitive decline[16], osteoporosis[17], breast cancer[18], end-stage renal disease[19], atherosclerosis[8], diabetes[20], coronary disease[21] and longevity[22]. Here, APOE is linked to diabetes mellitus.