Research for a New Age

Around the United States are more than a thousand men and women who travel, every 2 years, to Baltimore, Maryland. Some are in their nineties, some in their twenties, and the rest fall into each of the decades between. What they have in common is their destination in Baltimore - the NIA's Gerontology Research Center - and participation in a study that is answering some of the basic questions about what happens as people age.

The Baltimore Longitudinal Study of Aging (BLSA) is America's oldest continuing scientific examination of human aging. Initiated in 1958, its goal is to define normal aging - the changes and processes that affect all of us and can be attributed to aging per se rather than to the diseases that sometimes accompany aging. What Is Usual In Aging ? The BLSA's central question - what are the usual or universal aging processes ? - takes investigators in search of changes that occur in everyone. By studying the same individuals over time, longitudinally, they are gradually piecing together a picture of aging. Tests and measurements taken at 2 year intervals reveal what changes - or does not change - in the functioning of vital organs, the immune system, metabolism, hormone levels, personality, mental skills, and more. Emerging from the accumulating BLSA data are two major conclusions. One is that aging - "normal" aging - can be differentiated from disease. Bodily functions do change and some decline with age, but health problems do not inevitably follow, according to BLSA data. Many of the disorders of old age, including some of the most common and debilitating, have been traced to pathological processes rather than normal aging. The second key BLSA finding is that no single, chronological timetable of human aging exists. In fact, in terms of change and development, there are more differences among older people than among younger people. Even within one individual, organs can age at different rates. This suggests that genetic, life - style, and disease processes all affect the rate of aging and that several distinct processes are involved. The "normal aging" research trail has some major forks, including one that looks at sex and race differences in aging. Women joined the BLSA in 1978. Since then, some significant differences between the sexes as well as some similarities have emerged. Men's and women's immune responses seem to differ for example. Older women respond to bacteria and other antigens better than men, but their immune systems do not "remember" antigens as well. BLSA women over age 55 have limited antibodies to tetanus toxoid, suggesting that current immunization practices should be rethought for women. BLSA data are also expected to show whether and how the aging process differs between African Americans and whites. As part of the Vascular Initiative, for instance, investigators are looking at a common sign of aging, the gradual stiffening of the blood vessel walls, which occurs in both races and contributes to heart and other cardiovascular disease (CVD). Studying this process over time, they will learn about the cellular and other mechanisms involved and whether there are differences between Blacks and whites in the way this stiffening progresses. If significant differences show up, the findings could help explain why African Americans have higher rate of CVD than whites. They could also provide valuable leads in the search for ways to prevent and treat CVD in the both races.

A BLSA participant tests her strength. Studies show that muscle strength may be related to bone strength and the body's ability to use sugar (glucose tolerance) as people age.

Signs of Disease The Baltimore study gives researchers a chance to look for links between aging and disease. Investigators can examine the longitudinal data in search of the changes that precede and may predict clinical symptoms- the so-called precursors of disease, has shown how a substance called prostate-specific antigen or PSA can be used to detect prostate cancer in its earliest stages. Physicians have long known that PSA levels are elevated in men with prostate cancer and have used PSA levels to help diagnose this form of cancer. But the test has not been particularly accurate; many men who seem to have high levels do not turn out to have cancer. What the BLSA found, analyzing blood samples taken from men over a number of years, was that PSA levels jumped markedly in the presence of cancerous cells. This finding means that a sharp rise in PSA levels may be an important early marker or precursor of prostate cancer. This discovery has set the stage for more extensive studies of the prostate at the BLSA. The relatively small study of blood samples has evolved into a 10-year study of prostate growth which should answer questions about what kind and amount of growth can be considered normal and what is associated with disease.

Together, the BLSA and the Gerontology Research Center constitute one of the country's leading training resources for gerontology research, hosting many pre- and post-doctoral students each year as well as other outside collaborators.

		BLSA data show that hearing declines more quickly in men than women. Here a participant has her hearing tested, one of approximately 100 tests conducted in this ongoing study of how we age.
Spirometry tests at the BLSA measure lung capacity. The findings: About 40 percent of lung function is lost between 20 and 80. Smoking or disease can cause lung function to decline more quickly.		Dr. Nathan W. Shock, former Scientific Director of the National Institute on Aging, is often called the father of aging research. He developed the Baltimore Longitudinal Study of Aging into an internationally known research project.