Introduction to Special Section on Centenarians and Dementia

Extract

I am pleased to introduce this special section on centenarians and dementia. These articles were submitted as a group and are based on a symposium presented by the authors at the Annual Meeting of The Gerontological Society of America in November 1997. The three papers provide critical and diverse insights into this important topic. Because the oldest old are the fastest growing portion of the population in most industrialized and even some nonindustrialized nations, the importance of understanding the oldest old is clear. These articles focus on centenarians but vary considerably in both size and representativeness of this special population. Currently, it is very difficult to find large numbers of people who have survived to be centenarians whether the population base is a large metropolitan area such as Boston or even a larger but regional geographical area such as Georgia. Given these limitations, the data these three articles represent are especially unique. The authors use the data to examine the basis of dementia, a question that is likely to become increasingly important in the years to come as the number of elderly people in general, as well as the number of centenarians specifically, significantly increases. Some authors conclude that the probability of dementia increases significantly and linearly with age whereas others suggest a different pattern of occurrence indicating that dementia may develop in a linear fashion up until the achievement of late old age (i.e., 100 years). These authors suggest that survival to age 100 marks the beginning of a crossover effect, making the probability of dementia less likely and less predictable. Because the availability of children as support providers decreases as one achieves centenarian status and caregiving of people with dementia is very difficult, these findings have important clinical, policy, and service implications. Centenarians will have survived many of their children or will have children who are, themselves, 80 years old and likely to have their own significant health problems or functional limitations. Silver, Jilinskaia, and Perls 2001 report on 43 confirmed centenarians who are part of the New England Centenarian Study. The authors find a prevalence range of dementia at about two thirds, with one third of this population assessed as having no or very mild dementia. Hagberg, Alfredson, Poon, and Homma 2001 examined between 100 and 200 centenarians in each of three countries: Japan, Sweden, and the United States. They report a dementia prevalence rate between 40% and 63%. Hagberg and colleagues concur with the assumption of increased cognitive differentiation with age and report similar results across the three countries. Andersen-Ranberg, Vasegaard, and Jeune 2001, using a population-based survey of all persons living in Denmark during a specified 1-year period (approximately 276 people), found that 50% of their sample could be described as mildly to severely demented.