Global mortality from dementia: Application of a new method and results from the Global Burden of Disease Study 2019

Abstract

Introduction: Dementia is currently one of the leading causes of mortality globally, and mortality due to dementia will likely increase in the future along with corresponding increases in population growth and population aging. However, large inconsistencies in coding practices in vital registration systems over time and between countries complicate the estimation of global dementia mortality.

Methods: We meta-analyzed the excess risk of death in those with dementia and multiplied these estimates by the proportion of dementia deaths occurring in those with severe, end-stage disease to calculate the total number of deaths that could be attributed to dementia.

Results: We estimated that there were 1.62 million (95% uncertainty interval [UI]: 0.41-4.21) deaths globally due to dementia in 2019. More dementia deaths occurred in women (1.06 million [0.27-2.71]) than men (0.56 million [0.14-1.51]), largely but not entirely due to the higher life expectancy in women (age-standardized female-to-male ratio 1.19 [1.10-1.26]). Due to population aging, there was a large increase in all-age mortality rates from dementia between 1990 and 2019 (100.1% [89.1-117.5]). In 2019, deaths due to dementia ranked seventh globally in all ages and fourth among individuals 70 and older compared to deaths from other diseases estimated in the Global Burden of Disease (GBD) study.

Discussion: Mortality due to dementia represents a substantial global burden, and is expected to continue to grow into the future as an older, aging population expands globally.

Keywords: burden of disease; dementia; global health; mortality.

FIGURE 1

Analytical overview for the calculation of deaths attributable to dementia as an underlying cause of death. We multiplied prevalence estimates and attributable excess risk due to dementia from systematic review and meta‐analysis to calculate excess deaths due to dementia. Then, we estimated the proportion of excess dementia cases with end‐stage markers of disease markers by combining information from clinical data linked to death records and our meta‐analysis of mortality risk. We assumed deaths attributable to dementia as the underlying cause of death was the product of excess deaths due to dementia and the proportion of these deaths with markers of end‐stage disease

FIGURE 2

Attributable risk for all‐cause mortality due to dementia by age. Dots represent individual studies, and the line shows the results of the meta‐regression. Trimmed data points are those identified as outliers during the model‐fitting process; all other data points are included in the model. These estimates are applied across all years and geographies estimated in this study

FIGURE 3

Proportion of individuals who died with end‐stage conditions in the last year before death for all conditions combined and the conditions with the top five excess proportions, shown separately for individuals who died with and without dementia. These estimates are derived from linked clinical and death records from 2003 to 2017 in the Emilia Romagna region of Italy. They are assumed to apply globally and over the time period considered in this study

FIGURE 4

Both‐sex age‐standardized mortality rate per 100,000 due to dementia in 2019 by location. Values are expressed in rates per 100,000 population