Global burden of dementia in younger people: an analysis of data from the 2021 Global Burden of Disease Study

Abstract

Background: Dementia among younger people is rapidly emerging as a global health concern; however, comprehensive research on its shifting burden trends remains insufficient.

Methods: Data on the prevalence, incidence, mortality, and disability-adjusted life years (DALYs) associated with dementia occurring in individuals <70 years were extracted from the Global Burden of Diseases, Injuries, and Risk Factors Study 2021. Average annual percentage changes (AAPCs) were calculated to assess trends in age-specific rates (ASRs), including age-specific prevalence rates (ASPRs), age-specific incidence rates (ASIRs), age-specific mortality rates (ASMRs), and age-specific DALY rates (ASDRs) while young-onset dementia (YOD) burden trends were analyzed. The correlation between ASR/AAPC and the sociodemographic index (SDI) was evaluated.

Findings: In 2021, the global prevalence of dementia in individuals <70 years increased by 122.33%, with a 128% increase in new cases since 1990. Concurrently, deaths and DALYs of individuals <70 years with dementia rose by 119.28% and 119.77%, respectively. The AAPCs of YOD ASRs during 1990-2021 initially increased and then decreased with increasing SDI levels, with the highest AAPCs of ASPR (2.20 [95%CI: 2.08-2.32] per 100,000), ASIR (2.25 [95%CI: 2.06-2.45] per 100,000), ASMR (2.04 [95%CI: 1.93-2.15] per 100,000), and ASDR (2.06 [95%CI: 1.99-2.13] per 100,000) observed in middle-SDI levels. Additionally, females <70 years bore a higher burden of dementia globally, and gender differences are still widening.

Interpretation: The growth rate of YOD is accelerating, particularly in the middle to high SDI region with females bearing a disproportionately higher burden of YOD.

Funding: This work was supported by grants from the National High level Hospital Clinical Research Funding, CAMS Innovation Fund for Medical Sciences, and the National Natural Science Foundation of China.

Keywords: Global burden of disease; Incidence; Prevalence; Risk factors; Young-onset dementia.

Fig. 1

Dementia burden under 70 during 1990–2021 (A) The proportion of dementia in people under 70 to total AD from 1990 to 2021; (B) Number of prevalence, incidence, death, and DALYs for dementia under 70 from 1990 to 2021; (C) Age specific rate of prevalence, incidence, death, and DALYs for dementia under 70 from 1990 to 2021. DALY: Disability Adjusted Life Years; SDI: sociodemographic index.

Fig. 2

Joinpoint regression analysis of dementia prevalence, incidence, mortality, and DALYs in people under 70 from 1990 to 2021 (A) Joinpoint regression analysis of global dementia prevalence, incidence, mortality, and DALYs in people under 70 from 1990 to 2021. (B) Joinpoint regression analysis of dementia prevalence, incidence, mortality, and DALYs in people under 70 in high SDI region from 1990 to 2021 (C) Joinpoint regression analysis of dementia prevalence, incidence, mortality, and DALYs in people under 70 in high-middle SDI region from 1990 to 2021. (D) Joinpoint regression analysis of dementia prevalence, incidence, mortality, and DALYs in people under 70 in middle SDI region from 1990 to 2021 (E) Joinpoint regression analysis of dementia prevalence, incidence, mortality, and DALYs in people under 70 in low-middle SDI region from 1990 to 2021. (F) Joinpoint regression analysis of dementia prevalence, incidence, mortality, and DALYs in people under 70 in low SDI region from 1990 to 2021. APC: annual percentage change; AAPC: average annual percentage changes. DALYs: disability-adjusted life-years; SDI: sociodemographic index. ∗P < 0.05.

Fig. 3

Dementia burden under 70 by countries and territories (A) The number of prevalence, incidence, death and DALY of dementia under 70 in countries and territories by the year 2021; (B) The rate of prevalence, incidence, death and DALY of dementia under 70 in countries and territories by the year 2021; (C) The AAPC of prevalence, incidence, death and DALY of dementia burden under 70 in countries and territories by the year 2021. DALY: Disability-Adjusted Life Years; AAPC: average annual percentage changes. ASPR: age-specific prevalence rate; ASIR: age-specific incidence rate; ASMR: age-specific mortality rate; ASDR: age-specific DALY rate.

Fig. 4

Gender difference of dementia burden under 70 and dementia burden by age group during 1990–2021 (A) Gender difference of ASPR, ASIR, ASMR and ASDR of dementia burden under 70 during 1990–2021; (B) Gender difference of the number of prevalence, incidence, death and DALY of dementia under 70 during 1990–2021; (C) ASPR, ASIR, ASMR and ASDR of dementia under 70 during 1990–2021 by age group. ASPR: age-specific prevalence rate; ASIR: age-specific incidence rate; ASMR: age-specific mortality rate; ASDR: age-specific DALY rate; DALYs: disability-adjusted life-years; SDI: sociodemographic index.