THE BETULA PROSPECTIVE COHORT STUDY - MEMORY, HEALTH AND AGING

The objective of this article is to present an overview of a prospecti ve cohort study involving a total of 3,000 subjects whose ages were 35 , 40, 45, 50, 55, 60, 65, 70, 75, and 80 years when first tested. The design of the study includes three waves of data collection. The first of these waves was conducted in 1988-1990, the second in 1993-1995, a nd the third will be conducted in 1998-2000. One sample of 1,000 subje cts in these age cohorts underwent testing in 1988-1990 (100 subjects per cohort). This sample and two additional samples were tested in 199 3-1995 and will be tested again in 1998-2000. Subjects take part in ex tensive health and memory examinations, and interviews about social fa ctors. The memory testing covers a wide range of memory functions. The chief objectives of the study are to (a) examine the development of h ealth and memory in adulthood and old age; (b) determine early preclin ical signs of dementia; (c) determine risk factors for dementia; and ( d) assess premorbid memory function in subjects who are in accidents o r acquire diseases during the course of the study. Cross-sectional dat a from the first sample show a continuous age-related deterioration in tasks assessing episodic memory, no age-related deficit in semantic m emory tasks when educational level is partialed out, and no age effect s in priming. Finally, the relationships between subjective (i.e., sel f-rating) and objective (blood and urine parameters, blood pressure an d pulse, medication, recent contacts with a physician, and sensory fun ction) indexes of health, on the one hand, and memory performance, on the other, were in general relatively weak in all age groups. The heal th-memory relationship was completely mediated by age, whereas the age -memory relationship was only partially mediated by health.