Duke Longitudinal Studies

Purposes

The studies focused on “normal aging” in two senses: healthy aging and typical aging. Those persons studied were relatively healthy in that most were ambulatory community residents who were willing and able to come to the Duke Medical Center for tests and examination. The studies focused on more common or typical patterns and problems of aging rather than on abnormalities. The goal was to help distinguish between normal processes of aging and those that may accompany aging because of accident, stress, maladjustment, or disuse.

A second purpose was to use the longitudinal method of repeated observations over time—the best way to measure changes accurately—and the effect of one kind of change on another kind of change. The third purpose was to do as much interdisciplinary analysis as possible.

Themes

The five volumes reporting the results of these studies contain more than 100 specific findings. However, four general themes tie together the findings from several substantive areas.

• 1
  Declining health and physical function. This is the typical pattern of normal aging in most areas.
• 2
  Exceptions to physical decline. Substantial minorities show no decline and may even have improvement in sexual activity, cardiovascular function, hypertension, depression, health ratings, and so on.
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• 3
  Little or no decline in social and psychological function. Intelligence, as measured by the usual tests, shows much less decline over time than cross-sectional studies imply. Older adults also maintain their social contacts and do not disengage from their social networks.
• 4
  Wide variations in aging patterns. Individual variation tends to persist or increase with aging.

In summary, the Duke Longitudinal Studies found that normal aging includes many patterns of change, including stability and even improvement.