Aging, glucose metabolism, and diabetes: current concepts.

Glucose metabolism slows with the aging process, leading to diabetes mellitus and impaired glucose tolerance in approximately 25% of persons 65 years and older. A reduction in the biologic action of insulin, at a point beyond the insulin receptor (postbinding site), is primarily responsible for the reduced rate of glucose utilization. The contributions made by the "molecular" events of aging and environmental factors such as changes in diet, activity level, and body composition to the alterations in glucose metabolism are not well defined. Whether impaired glucose tolerance or diabetes mellitus contributes to morbidity or mortality in the aging population is not known.