Dementia in South and Southeast Asia: about 3% prevalence, and apparently rising

Design

Systematic review and meta-analysis of 31 observational studies (13 pooled)

Population

56,340 adults in South and Southeast Asian prevalence studies

Primary outcome

Prevalence of dementia and Alzheimer disease; associated factors

Effect

Dementia 3.0% (95% CI 2.0–5.0%); AD after 2010 8.0% (5.0–14.0%)

This systematic review included 31 observational studies from South and Southeast Asia, 13 of which (56,340 people) contributed to pooled prevalence.

Overall dementia prevalence was estimated at 3.0% (95% CI 2.0–5.0%), Alzheimer disease 2.0% and vascular dementia 1.0%. Alzheimer prevalence was 8.0% in studies after 2010 versus 1.0% before 2000. Mean age of Alzheimer onset was about 71. Higher literacy, adequate sleep, periodontal treatment and cognitive stimulation were associated with lower risk.

Heterogeneity was extreme (I² around 99%), so the pooled numbers are a rough guide at best. The rise over time may partly reflect better case-finding and older populations rather than a true increase in age-specific risk. Still, it is a reminder that dementia is not a rare diagnosis in Indian clinics and that low literacy, a common feature of older Indian patients, marks higher risk.

• Screen for cognitive impairment in older patients, using tools validated for low literacy where needed.
• Low educational attainment is a risk factor — and a source of false positives on standard tests.
• Address sleep, oral health and hearing as part of dementia risk reduction.
• Expect more patients presenting with cognitive complaints as the population ages.

Why it matters

It gives regional figures where most planning still relies on Western prevalence estimates.

Don't overread it

With I² near 99%, the pooled prevalence is highly uncertain, and the time trend may reflect better detection.

The statistics, in plain English

I² of 99% means almost all the variation between studies is real difference in settings and methods, not chance — so a single pooled figure hides a wide range across countries and studies.

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