Advances in Aging Research: The Baltimore Longitudinal Study of Aging

At 60 years and counting the National Institute on Aging's Baltimore Longitudinal Study of Aging (BLSA) is one of the longest-running studies in the world. The study was the first to ask a most basic question: What is normal aging?

There is still much to learn, but so far two major conclusions can be drawn from BLSA data. First, "normal" aging cannot be distinguished from disease. Although people's bodies change and can in some ways decline over time, these changes do not inevitably lead to diseases such as diabetes, hypertension, or dementia.

Second, no single, chronological timetable of human aging exists. We all age differently. In fact, in terms of change and development, there are more differences among older people than among younger people. Genetics, lifestyle, and disease processes affect the rate of aging between and within all individuals.

These fundamental changes in our thinking about age and disease have led the BLSA and the field of aging research in important new directions. As we further pinpoint the influences on how we age, we can also think about new and more effective interventions that may prevent disease and promote healthy aging.

Overall, by incorporating the study of disease into their understanding of normal aging, BLSA scientists have been able to:

• Quantify areas of natural, age-related decline and compare these declines with changes related to disease. For instance, researchers have studied natural versus disease-related changes in muscle quantity and strength, how these changes may be associated with other age-related physical and chemical changes, and the impact of these changes on longevity and physical ability.
• Build knowledge of the relationship between health risk factors and aging. Scientists have observed that the value of risk factors to predict disease may change with age. In one example, researchers calculated if the risk for heart disease could be better predicted by waist circumference along with body mass index (BMI, a measure of body fat based on height and weight), rather than by BMI alone. Waist circumference improved the predictive power of BMI for coronary risk in younger but not older people.
• Track trends for behaviors that promote health or risk for disease. In one BLSA study, scientists examined the dietary diaries of participants ages 27 to 88 from 1961 to 1987 to see how food choices changed over time. They found that in the late 1960's, fat and cholesterol in participants' diets declined while their consumption of fiber increased. Adults of all age groups followed this healthy eating trend. Older people were just as able as younger people to change their eating habits and benefitted from these changes as much as younger people.

Read more about normal aging and lessons from the BLSA.