- Gatz, Margaret;
- Mack, Wendy J;
- Chui, Helena C;
- Law, E Meng;
- Barisano, Giuseppe;
- Sutherland, M Linda;
- Sutherland, James D;
- Rodriguez, Daniel Eid;
- Gutierrez, Raul Quispe;
- Adrian, Juan Copajira;
- Cuata, Jesus Bani;
- Borenstein, Amy R;
- Walters, Ellen E;
- Irimia, Andrei;
- Rowan, Christopher J;
- Wann, L Samuel;
- Allam, Adel H;
- Thompson, Randall C;
- Miyamoto, Michael I;
- Michalik, David E;
- Cummings, Daniel K;
- Seabright, Edmond;
- Garcia, Angela R;
- Hooper, Paul L;
- Kraft, Thomas S;
- Finch, Caleb E;
- Thomas, Gregory S;
- Stieglitz, Jonathan;
- Trumble, Benjamin C;
- Gurven, Michael D;
- Kaplan, Hillard
Introduction
We evaluated the prevalence of dementia and mild cognitive impairment (MCI) in indigenous Tsimane and Moseten, who lead a subsistence lifestyle.Methods
Participants from population-based samples ≥ 60 years of age (n = 623) were assessed using adapted versions of the Modified Mini-Mental State Examination, informant interview, longitudinal cognitive testing and brain computed tomography (CT) scans.Results
Tsimane exhibited five cases of dementia (among n = 435; crude prevalence = 1.2%, 95% confidence interval [CI]: 0.4, 2.7); Moseten exhibited one case (among n = 169; crude prevalence = 0.6%, 95% CI: 0.0, 3.2), all age ≥ 80 years. 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 impairments, parkinsonian symptoms, and vascular calcification in the basal ganglia.Discussion
The prevalence of dementia in this cohort is among the lowest in the world. Widespread intracranial medial arterial calcifications suggest a previously unrecognized, non-Alzheimer's disease (AD) dementia phenotype.