Prevalence of dementia and mild cognitive impairment in indigenous Bolivian forager-horticulturalists.
Level 4 - case-series / case-control
Cross-sectional epidemiological prevalence study
PubMed 35262289 · doi:10.1002/alz.12626
What was done
Researchers evaluated the prevalence of dementia and mild cognitive impairment (MCI) among population-based samples of indigenous Tsimane and Moseten adults aged 60 and older (total n = 623) living a subsistence lifestyle in Bolivia. Evaluations utilized culturally adapted versions of the Modified Mini-Mental State Examination, informant interviews, longitudinal cognitive testing, and brain computed tomography (CT) scans.
What was found
Five cases of dementia were identified among 435 Tsimane participants (crude prevalence 1.2%, 95% CI: 0.4, 2.7), and one case was identified among 169 Moseten participants (crude prevalence 0.6%, 95% CI: 0.0, 3.2), with all cases occurring in individuals aged 80 or older. Age-standardized MCI prevalence was 7.7% (95% CI: 5.2, 10.3) in Tsimane and 9.8% (95% CI: 4.9, 14.6) in Moseten. Cognitive impairment was associated with visuospatial deficits, parkinsonian symptoms, and vascular calcification in the basal ganglia.
Why it matters
This cohort exhibits some of the lowest dementia prevalence rates recorded globally, suggesting that a non-industrial subsistence lifestyle and its associated cardiovascular health may protect against common forms of dementia.
Limits
The total number of dementia cases identified was very small (6 cases total), yielding wide confidence intervals around prevalence estimates. Findings reflect unique forager-horticulturalist subsistence environments and may not generalize to urbanized or industrialized populations.
Cited by
- context Studies of indigenous hunter-gatherer populations like the Hadza in Tanzania and rural agrarian groups like the Yoruba find that Alzheimer's and vascular dementia are exceptionally rare.