Rising burden of Alzheimer's disease and other dementias in Sierra Leone, 1990-2023: analysis of Global Burden of Disease 2023 estimates.

Abstract

Background: Dementia is an increasing cause of disability and mortality worldwide. Primary dementia surveillance data remain limited in many low-income settings, including Sierra Leone.

Objective: To describe trends in Burden of Disease (GBD) 2023 modelled estimates for Alzheimer's disease and other dementias in Sierra Leone from 1990 to 2023, and to decompose the change in estimated deaths into demographic and age-specific mortality components.

Methods: We conducted a secondary analysis of GBD 2023 estimates for the cause category 'Alzheimer's disease and other dementias' in Sierra Leone. We analysed estimated counts and age-standardised rates for prevalence, deaths, years of life lost, years lived with disability and disability-adjusted life years (DALYs) stratified by age and sex. Temporal trends were described with log-linear regression to estimate annual per cent change, and a three-component decomposition attributed changes in deaths to population growth, ageing and age-specific mortality.

Results: GCD 2023 estimated that dementia deaths in Sierra Leone increased from 188 in 1990 to 474 in 2023, an absolute increase of 286 estimated deaths (152% relative increase). Estimated DALYs increased from 3703 to 7440. The modelled age-standardised death rate rose 26.8% (16.3 to 20.7 per 100 000) and the age-standardised DALY rate 13.4% (293.7 to 333.2 per 100 000). Estimated prevalent cases increased from 5647 to 8887, while the modelled age-standardised prevalence rate declined from 430.7 to 404.0 per 100 000 population. The log-linear annual percentage change was +1.02% for age-standardised death rates, +0.60% for DALY rates and -0.18% for prevalence rates. Decomposition attributed 62% of the increase in estimated deaths to changes in age-specific mortality, 30% to population growth and 8% to population ageing.

Conclusions: GBD 2023 estimates show a rising absolute burden of dementia in Sierra Leone, against a background of limited local surveillance and mortality ascertainment.