Carbohydrate metabolism in the elderly.

In this short review we summarize the effect of age on glucose homeostasis. The concept of decreased glucose tolerance with increasing age is introduced, followed by evidence for this phenomenon. Specifically we review the evidence for changes in fasting glucose as a function of age and the effect of age on HbA1c. The role of age on hepatic glucose production and glucose uptake is then discussed in detail and we review the evidence that supports the concept that with advancing age hepatic glucose sensitivity to insulin is unaltered. We then review the large evidence for the role of age on the purported decrease in peripheral tissue sensitivity to insulin and conclude that the issue is unsettled. The decrease attributed to age is no longer significant when confounders are controlled for, the largest being obesity. We next present evidence that beta-cell sensitivity to glucose remains intact with aging. A review of age-related disorders due to hyperglycemia and confounding effects on the relationships of age and glucose tolerance is presented next. Finally we present new evidence that when the revised criteria for the diagnosis of type 2 diabetics as proposed by the American Diabetes Association and WHO are used, a greater percentage of the elderly will not be diagnosed. We conclude that, although glucose intolerance increases with aging, which is accompanied with other disorders, it is possible to ameliorate this effect with alteration of diet and exercise.