Dementia and Survival at Extreme Old Ages. a Prospective Cohort Study of Health Trajectories Among German Centenarians and Nonagenarians Using Health Claims Data.

Gabriele Doblhammer, University of Rostock
Alexander Barth, Rostock Center for the Study of Demographic Change

Whether centenarians and nonagenarians, the fastest growing age groups in high-income countries, will pose a severe burden for societies depends foremost on their physical and cognitive health. We explore whether dementia, major chronic diseases, and diseases related to quality of life are compressed into the last year of life among long-lived individuals by using a large, nationally representative sample of Germany''s biggest health insurer. We followed the 1908-1913 birth cohorts from age 95 to 100 (n=2,865 individuals and 2,397 deaths), and the 1918-1923 birth cohorts from age 85 to 90 (n=17,013 individuals and 8,417 deaths) to analyze disease trajectories in relation to age and age at death. Furthermore, we assess the association of suffering from dementia and other conditions with surviving to the 100th and the 90th birthday by estimating Cox proportional hazard models. Among all diseases dementia and heart disease were special in terms of the advantage of centenarians and nonagenarians: Centenarians, who, at age 95, started with 28 (95% CI: 24-32) dementia cases per 100 population reached 54 cases at age 100. At age 95, among those who died at age 95 the prevalence was 55 cases (95% CI=52-59); at the same age it was 43 cases (95% CI: 37-49) among those who died at age 99. In the multivariate analysis of the older cohort, dementia dominated the risk of dying before age 100 with a hazard ratio (HR) of 1.66 (95% CI: 1.53-1.81). Results were even stronger for the younger cohort.

For most diseases, at the same age, those living longer had a lower prevalence than those who died. Our study suggests that survival at these high ages first of all depends on the presence of dementia with heart disease and pneumonia playing an important role as immediate causes of death.

Presented in Session 1192: Mortality and Longevity