Longitudinal Studies on Aging and the Development of Geriatrics in North America

John Morley has provided us with an amazingly comprehensive review of the history of geriatrics in relatively few pages (1). He ‘‘hits the high points’’ and provides us with a range of tidbits to tweak our interest in the topic. At a time when we are less inclined to look at our histories, we do well to consider the foundations upon which our specialties of geriatric medicine and psychiatry are based. I would emphasize one area that Dr. Morley addresses briefly— longitudinal studies on aging in North America. Geriatrics in the United States was an appendage to medical science until two key studies emerged that laid the foundation for modern geriatric medicine in North America—the Duke Longitudinal Studies on Aging (2) and the Baltimore Longitudinal Study (3). Later longitudinal studies have emerged, such as the Berlin Aging Study (BASE) (4), yet these two studies deserve special attention given their historical contributions to the health care of older adults. The first Duke Longitudinal Study was launched in 1955 with 271 persons aged 60–90 years and these subjects were followed for 20 years (5). The Baltimore Longitudinal Study was launched in 1958 and was initially restricted to men (as of 1985, 1243 men had been examined at least once) (6). The investigators of both studies had similar goals—to study and document the normal aging process from which the pathology of aging could be distinguished. Both studies recruited relatively healthy subjects by design, and instituted both an interdisciplinary and a cohort perspective (that is, repeated observations over time to determine change). The concept of normal aging has been debated since the inception of these studies, and that debate has been magnified in recent years with the emergence of a new generation of studies of successful aging (2,7). The investigators did not define normal aging elaborately but rather operationalized their constructs by recruiting subjects who were healthy, who were living in the community, and who were willing to be studied over time. More recently, some investigators have urged a distinction between ‘‘usual’’ and ‘‘successful’’ aging within the construct of normal aging (7,8). Those who are aging successfully suffer few if any functional problems. This debate will undoubtedly continue and will evolve, for older adults today may not reflect older adults in the future (9). Fortunately, these debates have spawned numerous empirical studies from which we can learn. The key findings from these studies (5) are, first, health and physical function clearly decline over time, yet the rate of decline varies widely across people and across organ systems within individuals. Second, there are exceptions to the rule of decline. For example, many elders exhibit no decline but even an increase in sexual interest and activity with aging. Third, until very late in life, there is little or no decline in psychological and social function unless illness severely compromises the older adult. And, finally, we cannot assume that general patterns will breed true in our individual patients. If we have learned anything about aging, we have learned that it is best characterized by variability. Why are these studies critical to the emergence of geriatrics in the United States? First, geriatrics was nascent before these studies emerged. Presentation of findings not only in gerontology and geriatrics journals but also in mainstream journals provided an introduction to the basic sciences underlying geriatrics for scientists and clinicians alike. Gerontologic science, in turn, recruited many renowned mainstream medical scientists to geriatrics, such as Paul Beeson, David Solomon, and Gene Stollerman. Second, these studies were inherently interdisciplinary and multidimensional. Therefore, the emerging clinical practice of geriatrics in the United States was interdisciplinary, including internists, family physicians, psychiatrists, social workers, nurses, physical therapists, and rehabilitation specialists. Comprehensive Geriatric Assessment (10) is a direct consequence of these interdisciplinary roots. Third, geriatricians in the United States have recognized that aging does not begin at a particular age. Geriatricians have recognized the importance of health and health behaviors in midlife as critical to the health of older adults. We owe much to the now-historical longitudinal studies of aging, and no history of geriatrics in the United States is complete without the recognition of their central foundational role.