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This chapter addresses the following Geriatric Fellowship Curriculum Milestone: #8


Learning Objectives

  • Describe the changing demographic characteristics and longevity of the aging population in the United States and worldwide.

  • Identify the leading causes of death and common diseases affecting older adults.

  • Gain understanding of the occurrence, determinants, and consequences of disability in the older population.

Key Clinical Points

  1. Improvements in survival over the last century have resulted in a population with a large proportion of individuals who will survive to advanced old age.

  2. Although there is much useful information gained by observing individual diseases responsible for mortality and disability, a full picture of disease status in the older population should include consideration of co-occurring diseases.

  3. Disability status measures are the best predictors of adverse health outcome, as disability measures capture the impact of the presence and severity of multiple pathologies, as well as the potential synergistic effects of these conditions, on overall health status.


Over the past century there have been truly remarkable changes in the numbers and characteristics of older persons throughout the world. The growth of the older population has resulted from a general increase in the overall population size but has been particularly affected by major declines in several of the leading causes of mortality. The increased survival of older persons has also been accompanied by declining birth rates, so the proportion of the population aged 65 and older has increased dramatically and will continue to increase for the next 50 years. These demographic transformations have an effect on society that reverberates well beyond the increased medical care needs associated with an older population.

As more people live to advanced old age, it is important to gain a greater understanding of more than just the individual diseases that affect them. It is critical to appreciate the global picture of older persons who may have multiple chronic conditions, decrements in functional abilities, and social and psychological problems that may have an impact on many facets of their health and quality of life. In contrast to the previous stereotype, older people become more heterogeneous, not more alike, as they age, and understanding this process is one of the key challenges of geriatric medicine. Adding to the clinical perspective on single patients or small samples of patients, geriatric epidemiology has provided a useful tool with which to approach these challenges by studying representative populations of older persons. Going beyond the demographic focus of counting and projecting the number of older people in the population, epidemiology has made additional contributions to our understanding of the health status and functional trajectory of the older population. In the past 25 years, epidemiologic researchers either have utilized previously initiated cohort studies that include persons who have aged during the study or have begun new cohorts focusing on older people. These epidemiologic studies have assessed the distribution ...

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