Is there a relationship between insulin resistance and frailty syndrome?

Due to the fact that the percentage of aged subjects in the populations of industrialized countries is dramatically increasing, the scientific community has been obligated to focus their attention on age related disease states and peculiar consequences of aging such as, frailty. Frailty is defined as a syndrome of decreased reserve and resistance to stressors and is clinically expressed as muscle weakness, poor exercise tolerance, factors related to body composition, sarcopenia, and lower extremity mobility. Some biochemical markers of frailty in older persons, including pro-inflammatory markers, hormones and free radicals have been suggested. However, there is growing evidence that a rise in insulin resistance [IR] occurs as individuals age and IR is not only considered a simple metabolic finding, but has been identified as a major risk factor for many age-related diseases due to altered lipid metabolism, increased inflammatory state, impaired endothelial functioning, pro-thrombotic status and atherosclerosis. Considering that IR is related to many of the clinical features of frailty such as, skeletal muscle weakness, lower extremity mobility disability, cognitive decline and body composition changes, we will analyze the relationships among IR and such individual components while highlighting potential pathophysiologic mechanisms of IR on the activation of the downward spiral of the frailty syndrome in older persons. In particular, we will address the issue that IR may also be considered a pivotal biological component of some clinical aspects of the frailty syndrome in aging individuals.