My 800th curation is a 2021 human diet and lifestyle study:
“Brain atrophy is correlated with risk of cognitive impairment, functional decline, and dementia. This study (a) examines the statistical association between brain volume (BV) and age for Tsimane, and (b) compares this association to that of 3 industrialized populations in the United States and Europe.
Tsimane forager-horticulturists of Bolivia have the lowest prevalence of coronary atherosclerosis of any studied population, and present few cardiovascular disease (CVD) risk factors. They have a high burden of infections and inflammation, reflected by biomarkers of chronic immune activation, including higher leukocytes counts, faster erythrocyte sedimentation rates, and higher levels of C-reactive protein, interleukin-6, and immunoglobulin-E than in Americans of all ages.
The Tsimane have endemic polyparasitism involving helminths and frequent gastrointestinal illness. Most morbidity and mortality in this population is due to infections.
The Tsimane exhibit smaller age-related BV declines relative to industrialized populations, suggesting that their low CVD burden outweighs their high, infection-driven inflammatory risk. If:
- Cross-sectional data (which we believe are population-representative of Tsimane adults aged 40 and older) represent well the average life course of individuals; and
- The Tsimane are representative of the baseline case prior to urbanization;
these results suggest a ~70% increase in the rates of age-dependent BV decrease accompanying industrialized lifestyles.
Despite its limitations, this study suggests:
- Brain atrophy may be slowed substantially by lifestyles associated with very low CVD risk; and
- There is ample scope for interventions to improve brain health, even in the presence of chronically high systemic inflammation.
Lastly, the slow rate of age-dependent BV decrease in the Tsimane raises new questions about dementia, given the role of both infections and vascular factors in dementia risk.”
https://gurven.anth.ucsb.edu/sites/default/files/sitefiles/papers/irimiaetal2021.pdf “The indigenous South American Tsimane exhibit relatively modest decrease in brain volume with age despite high systemic inflammation”
I came across this study by its citation in Dr. Paul Clayton’s 2021 blog post We’ve got to get ourselves back to the garden.