More people are going to live longer. Proportion of those above age 90 in the population is increasing in high income countries.It has been argued previously that this increased longevity meant declining health for the elderly. (failure of success hypothesis i.e. longevity at expense of quality).There is not much data on health of above 90 age group.
Among 65-85 group ( the younger elderly), studies indicate more disease, but better physical and cognitive functioning THAN the earlier birth cohorts ( i.e. Flynn effect).What about the 90 plus cohort ? Are they living longer with poorer cognitive and functioning ability?
Kaare Christensen and team of researchers looked at health and functioning of two complete Danish birth cohorts of nonagenarians born 10 years apart, in 1905 and 1915. The two surveys (1905 cohort surveyed in 1998 & 1915 court surveyed in 2010) used the same design and survey instrument. Assessment consisted of an interview, physical and cognitive tests, and the collection of biological material
Chances of surviving in to 90 plus has increased. Chance of reaching 95 years was 32% higher in 1915 cohort (3.93% vs 2.98%).Recent cohort members are functioning better. Despite being 2.2 years older , the 1915 cohort performed better than 1905 cohort in both cognitive functioning and activities of daily living . Average MMSE scores were higher in 1915 cohort.23% of 1915 cohort had MMSE score between 28-30. This was only seen in 13% in 1905 cohort.
Conclusion: More people are surviving to 90 plus. More of these individuals are having better cognitive functioning. More 90 plus individuals are able to function better than members of earlier cohorts.
Summary of the article:
Christensen K, Thinggaard M, Oksuzyan A, Steenstrup T, Andersen-Ranberg K, Jeune B, McGue M, Vaupel JW.
Lancet. 2013 Nov 2;382(9903):1507-13.