Disability rates may not increase with very old age

A report published online this week in the Proceedings of the National Academy of Sciences confirmed that increasing rates of disability may not be inevitable among the very old, who are the fastest growing population segment in the Western world. In an article entitled, “Exceptional longevity does not result in exceptional levels of disability,” researchers in Denmark and at the Max Planck Institute in Germany conclude that the concern regarding an increased burden of care-giving associated with more people joining the ranks of the very old may be unfounded.

Kaare Christensen at the Danish Aging Research Center at the University of Southern Denmark and colleagues studied 2,262 Danish men and women born in 1905. The subjects were surveyed in 1998, and in 2000, 2003, and 2005 to evaluate physical functioning, cognitive function, and depression levels.

At the beginning of the study, 39 percent of the subjects were classified as independent: defined as being able to perform activities of daily living without assistance and having adequate cognitive function. This percentage declined by an additional 6 percent by 2005 among the 166 surviving participants, an amount considered “modest”.

The authors write that with improved medical treatment and education, as well as a reduction in the number of those who smoke among those entering the oldest-old population, a decrease in disability among this age group can be expected.

“It has been postulated that life extension would provide only increased chances of being frail and existing in a vegetative state, with huge personal and societal costs,” the authors write. “Our study does not support this grim prediction. On the contrary, our findings suggest that the characteristics of a cohort do not change much in an age range from 92 to 100 years in central domains such as physical and cognitive functions and depression symptomatology.”

“Our finding also suggests that individuals who survive into the highest ages have a health profile that is similar in many aspects to that of individuals who are 7 or 8 years younger,” they conclude. “This suggests that most individuals can expect to experience physical decline before they die, but the postponement of this individual decline makes it possible for us to live into the fourth age.”