Epidemiology and Diagnosis of Dementia

Dementia comprises a spectrum of progressive neurocognitive disorders marked by impairments in memory, executive function, language and behaviour. Globally, over 50 million people live with dementia, and population ageing and growth are projected to treble this figure by 2050. Although overall age-standardised prevalence has remained relatively stable, marked geographic and socioeconomic variation persists. Low- and middle-income regions face the steepest relative increases, driven by limited preventive efforts and diagnostic capacity. Key modifiable risk factors include midlife hypertension, diabetes, obesity, smoking and low educational attainment, while non-modifiable factors such as age, genetics and sex influence individual susceptibility. Diagnosis has evolved from purely clinical criteria and neuropsychological batteries to incorporate biomarkers—cerebrospinal fluid tau and amyloid assays, PET imaging and emerging blood tests—and digital cognitive assessments. Despite these advances, underdiagnosis is common, with many cases identified late in the disease course. Improving surveillance, broadening access to standardized diagnostic pathways and integrating risk-reduction strategies remain critical to mitigating the personal, societal and economic impacts of dementia.

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Epidemiology and Diagnosis of Dementia publication trend

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

Technical terms

Prevalence: The proportion of a population living with dementia at a given time.

Incidence: The rate of new dementia cases occurring in a population over a specified period.

Age-standardised prevalence: Prevalence adjusted to a standard age distribution to allow comparisons across populations.

Biomarker: A measurable indicator of pathological processes, such as cerebrospinal fluid amyloid-β or tau levels.

Mild cognitive impairment (MCI): A transitional stage of cognitive decline with preserved functional independence.

Cognitive reserve: The brain’s resilience to neuropathological damage, influenced by education and life experiences.

References

1. Sex differences in dementia risk and risk factors: Individual‐participant data analysis using 21 cohorts across six continents from the COSMIC consortium. Alzheimer's & Dementia (2023).
2. Estimation of the global prevalence of dementia in 2019 and forecasted prevalence in 2050: an analysis for the Global Burden of Disease Study 2019. The Lancet Public Health (2022).
3. Association of Socioeconomic Status With Dementia Diagnosis Among Older Adults in Denmark. JAMA Network Open (2021).