Glucose regulation and brain aging.

Blood glucose regulation is not only a complex phenomenon but glucose regulatory levels also vary significantly across individuals. Thus, whereas individuals compromised with moderately elevated blood glucose levels are diagnosed as having impaired glucose tolerance, excessive blood glucose levels render a Type II diabetes diagnosis. Type II diabetes prevalence rates in the adult population have been estimated to be between 6 and 10 percent. Although Type II diabetes has been typically associated with older people, the disease has become much more common among young adults and children. It has become increasingly evident that protracted glucose tolerance impairment usually precedes a type II diabetes diagnosis, although impaired glucose tolerance will not necessarily progress to a diabetic state. Furthermore, a number of studies have shown that impaired glucose tolerance or type II diabetes is associated with impaired cognitive function in older subjects. In addition, we recently found that cognitive deficits are also associated with moderately impaired glucose regulation in young healthy volunteers. These data, although in need of confirmation and extension, suggest that impaired glucose tolerance is associated with impaired cognition, independent of age. Moreover, since impaired glucose tolerance is more prevalent than diabetes across all ages, then our finding lead to the implication that impaired cognitive function may be more prevalent in the general population than previously estimated. Finally, the dysfunction of glucoregulatory mechanisms may be an important intervening factor when studying the evolution of cognitive function through the aging process.