What is a healthy lifestyle? How dementia prevalence is impacted by a subsistence lifestyle
Indigenous Tsimane and Moseten people, who live pre-industrial subsistence lifestyles, are among those with the lowest prevalence of dementia in the world.
The newest study from The Tsimane Health and Life History Project [1], assessed the cognitive function of over–60’s within indigenous Bolivian Amazon populations and discovered the dementia rate was among the lowest in the world. The results indicate how aspects of pre-industrialized lifestyles may provide benefits for our brain’s health as we age.
The 17,000 Tsimane live active subsistence lifestyles. They farm and hunt with hand tools, gather food and resources from the forest, and have minimal access to electricity, clean water, sewage treatment and medicines. The Moseten population of 3,000 also farm for subsistence; however, they live closer to towns and have access to schools, clean water and medical services.
To diagnose those over 60 years old with dementia or cognitive impairment, researchers utilized a combination of CT scans, cognitive and neurological evaluations, and culturally appropriate questionnaires conducted by a local team of translators and physicians.
Of the 435 Tsimane and 169 Moseten assessed, only six cases of dementia were identified. Within each population approximately 1% suffered from dementia, which is a stark contrast to the dementia prevalence in the US of 11% for over-65’s. When assessing cognitive function, 8% of Tsimane and 10% of Moseten were diagnosed with mild cognitive impairment. These rates are more comparable to countries like the USA with post-industrial lifestyles.
Placing this into a global perspective, researchers compared their results to 15 studies of indigenous populations across Australia, North America, Guam and Brazil, of which dementia prevalence ranged from 0.5–20%.
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This study builds upon years of work with the Tsimane populations by The Tsimane Health and Life History Project and collaboration between multiple international institutes. Previous findings have highlighted that Tsimane people exhibit a 70% slower decrease in brain volume with age than US and European populations, indicating lesser risk of cognitive decline during old age [2].
APOE4, a gene associated with increased risk of Alzheimer’s disease and heart disease in industrialized countries, was observed to be beneficial for pathogen response and did not increase the risk of heart disease within active Tsimane populations. APOE4 carriers demonstrated reduced innate inflammation when not infected and high levels of low-density lipoprotein cholesterol at low body mass indices [3].
The remarkable health of Tsimane is not only limited to brain aging. In 2017, it was also shown Tsimane people have the lowest prevalence of coronary atherosclerosis of any studied population in the world [4].
When compared to the Tsimane, the lifestyles of higher-income countries may lead to the increased rates of heart disease and cognitive decline with age in these populations. Future analysis of the population will improve understanding of disease development and how our lifestyle may influence associated risk factors.
“We’re in a race for solutions to the growing prevalence of Alzheimer’s disease and related dementias,” added senior author Hillard Kaplan (Chapman University; CA, USA) and director of The Tsimane Health and Life History Project). “Looking at these diverse populations augments and accelerates our understanding of these diseases and generate new insights.”
