Epidemiology of Dementia in Aging Populations

The global burden of dementia is rising in parallel with population ageing, transforming it into a major public health challenge. Prevalence increases steeply with advancing age, with figures doubling every five years after the age of 65. Although Alzheimer’s disease remains the most common cause, vascular cognitive impairment, Lewy body disease and frontotemporal degeneration contribute substantially to the overall caseload. Numerous studies highlight the interplay of non‐modifiable factors such as age, sex and genetic susceptibility with modifiable risks including low educational attainment, cardiovascular disease, physical inactivity and social deprivation. Geographic and socioeconomic inequalities drive marked regional variations: low‐ and middle‐income countries are experiencing the fastest increases in both prevalence and mortality, often compounded by limited diagnostic capacity and scant long‐term care infrastructure. In high‐income settings, the emphasis has shifted towards early detection through biomarkers and preventive interventions aimed at vascular health and cognitive reserve. By contrast, many regions in the Global South face challenges in harmonising research protocols, delivering equitable access to diagnostic tools and tailoring interventions to local cultural contexts. The epidemiological evidence underscores a pressing need for integrated surveillance systems, regionally sensitive public health strategies and global collaboration to monitor trends, identify at‐risk populations and deploy cost‐effective prevention and care pathways.

Research from Nature Portfolio

Recent large‐scale analyses have applied machine‐learning approaches to disentangle the relative contributions of sociodemographic, metabolic and psychosocial factors to cognitive trajectories in older adults. One investigation of tens of thousands of participants across Latin American countries revealed that social determinants and mental health symptoms often exert stronger influences on cognitive and functional ageing than chronological age or sex. A complementary meta‐analysis pooling data from diverse cohort and interventional studies demonstrated heterogeneous effects of risk factors on cognition and functional ability, with modest impacts for conventional targets such as hypertension and cholesterol, but larger effects attributed to mental health and social adversity. These findings challenge traditional one‐size‐fits‐all models of healthy ageing, emphasising the need for regionally tailored risk assessments and interventions that address underlying inequities.

Epidemiology of Dementia in Aging Populations publication trend

The graph below shows the total number of articles in epidemiology of dementia in aging populations across all publications each year (not limited to Nature Index journals).

Technical terms

Prevalence: Proportion of a population living with dementia at a given point in time.

Incidence: Rate of new dementia cases occurring in a defined population over a specified period.

Biomarker: A measurable indicator of a pathological process, e.g. a protein in cerebrospinal fluid or a brain‐imaging signal.

Functional ability: Capacity to perform daily activities and maintain independence.

Social determinants of health: Non‐medical factors such as education, income and living conditions that influence health outcomes.

References

1. Factors associated with healthy aging in Latin American populations. Nature Medicine (2023).
2. Healthy aging meta-analyses and scoping review of risk factors across Latin America reveal large heterogeneity and weak predictive models. Nature Aging (2024).
3. Biomarkers of neurodegeneration across the Global South. The Lancet Healthy Longevity (2024).
4. Addressing the gaps between socioeconomic disparities and biological models of dementia. Brain (2023).
5. Dementia in low-income and middle-income countries: Different realities mandate tailored solutions. PLOS Medicine (2017).
6. Prevalence of dementia in Latin America and Caribbean countries: Systematic review and meta-analyses exploring age, sex, rurality, and education as possible determinants. Ageing Research Reviews (2022).