Life expectancy with and without dementia: a population-based study of dementia burden and preventive potential

Abstract

Reliable population estimates of life-expectancy with dementia are required for shaping health care policy. 10,348 persons from the population-based Rotterdam Study were followed from 1990-2015 for dementia and death. We created multi-state lifetables, and assessed the effect of postponing disease onset. During 120,673 person-years, 1,666 persons developed dementia, and 6,150 died. Overall life-expectancy of women ranged from 18.0 years (95% confidence interval:17.8-18.2) at age 65 to 2.3 years (2.2-2.3) at age 95. Of total life-expectancy at age 65, 5.7%, i.e. 1.0 year (1.0-1.1), was lived with dementia, increasing with age to 42.1% (1.0 year,0.9-1.0) of life-expectancy at age 95. For men, overall life-expectancy ranged from 15.6 years (15.4-15.9) at age 65 to 1.8 years (1.7-1.8) at age 95, of which 3.7% (0.6 year,0.5-0.6) and 35.3% (0.6 year,0.5-0.7) was lived with dementia, respectively. Postponing dementia onset by 1-3 years resulted in 25-57% reductions in years lived with dementia. Survival after dementia diagnosis ranged from 6.7 (95%CI 5.3-8.1) years when diagnosed before age 70, to 2.6 years (2.3-2.9) >90 years. Dementia places a large burden on individuals and society in terms of healthy life-years lost, but this is potentially highly amendable by preventive interventions at the population level.