The Endocrinology of Aging (Beckman Conference‪)‬

Changes in medical care, particularly the advent of anti-biotics, public health measures, and vaccinations, have dramatically increased the average life expectancy in the United States in this century (1). With these increases has come the concern not merely that life should be extended, but that useful independent life should be lengthened (1, 2). As such, considerable time and effort has been expended in defining risk factors for institutionalization or frailty syndromes. These are described as morbid and premorbid changes in function that either limit or potentially limit free and independent life. Table 1 describes the two such general frailty syndromes, i.e., individuals at risk for or with multiple or prolonged hospitalizations and recoveries. The causes of such syndromes are protean, but they include multiple comorbid conditions. Thus, older frail individuals frequently have multiple problems: for example, congestive heart failure, hypertension, cerebrovascular accidents, peripheral vascular disease, and/or diabetes. The intermediate causes for this frailty syndrome include loss of organ system reserve and polypharmacy. A second proximate cause for prolonged hospitalization and/or recovery are serendipitous events such as falls and fractures. Such events surely limit independent functional living. The intermediate causes for falls and fractures are prolonged reaction time, loss of strength, poor vision, and/or osteoporosis. The initial causes of the intermediate causes of both types of frailty syndromes are also numerous. For the purpose of the review, however, we will be concerned with how age-related changes in endocrine function may lead to these intermediate and proximate causes of frailty. Changes in endocrine systems potentially figure in many of these frailty syndromes. A second issue that we will consider is how pharmacologic intervention may reverse or slow their effects. The purpose of this review is to describe some of the changes in endocrine function, how they relate to the aging, how they might relate to the development of frailty syndromes, and finally, how remedial interventions may alter the changes to prevent the frailty syndromes. Most individuals enter adulthood with a substantial physiologic reserve in multiple organ systems, including the endocrine function. Aging and intercurrent pathologies will eventually consume this reserve. As these processes continue, function will then be compromised. It should be obvious from this introduction, however, that given the appropriate pathology, virtually any endocrine gland might be subject to the effects of aging. In addition, many endocrine functions are so intertwined that diminution in function of one must adversely affect the remainder.