Document Type
Article
Publication Date
3-20-2023
Abstract
Little is known about brain aging or dementia in nonindustrialized environments that are similar to how humans lived throughout evolutionary history. This paper examines brain volume (BV) in middle and old age among two indigenous South American populations, the Tsimane and Moseten, whose lifestyles and environments diverge from those in high-income nations. With a sample of 1,165 individuals aged 40 to 94, we analyze population differences in cross-sectional rates of decline in BV with age. We also assess the relationships of BV with energy biomarkers and arterial disease and compare them against findings in industrialized contexts. The analyses test three hypotheses derived from an evolutionary model of brain health, which we call the embarrassment of riches (EOR). The model hypothesizes that food energy was positively associated with late life BV in the physically active, food-limited past, but excess body mass and adiposity are now associated with reduced BV in industrialized societies in middle and older ages. We find that the relationship of BV with both non-HDL cholesterol and body mass index is curvilinear, positive from the lowest values to 1.4 to 1.6 SDs above the mean, and negative from that value to the highest values. The more acculturated Moseten exhibit a steeper decrease in BV with age than Tsimane, but still shallower than US and European populations. Lastly, aortic arteriosclerosis is associated with lower BV. Complemented by findings from the United States and Europe, our results are consistent with the EOR model, with implications for interventions to improve brain health.
Recommended Citation
H. Kaplan et al., Brain volume, energy balance, and cardiovascular health in two nonindustrial South American populations. PNAS 120(13), e2205448120 (2023). https://doi.org/10.1073/pnas.2205448120
Peer Reviewed
1
Copyright
The authors
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Included in
Economic Theory Commons, Indigenous Studies Commons, Latin American Studies Commons, Medical Humanities Commons, Nervous System Commons, Nervous System Diseases Commons, Other Economics Commons, Other International and Area Studies Commons
Comments
This article was originally published in PNAS, volume 120, issue 13, in 2023. https://doi.org/10.1073/pnas.2205448120