[Concept and clinical characteristics of diabetes mellitus in the elderly]

Both decreased insulin secretion and insulin resistance are two major factors of impaired glucose tolerance (IGT) in the elderly. Up to now, decreased lean body mass and relatively increased fat mass, so-called sarcopenia or sarcopenic obesity, contribute to insulin resistance in the elderly. However, recent reports indicate that muscle mitochondrial function is reduced in aging, and this age-associated decline in mitochondrial function contributes to insulin resistance in the elderly. In addition, exercise intervention to IGT in the elderly is more effective to reduce in the incidence of type 2 diabetes than in younger people. Exercise seems to improve insulin resistance through mitochondrial function by activating AMP-activated protein kinase(AMPK) and PPARgamma coactivator-1alpha (PGC-1alpha). Because cognitive impairment is a most crucial factor plunging into frailty in diabetic elderly, diabetic control would be very important in preventing cognitive decline as well as vascular events. However, comprehensive management of diabetes, including dyslipidemia and hypertension, might contribute to the prevention of declines in cognitive function in older diabetic patients.