Dementia prevalence low among Bolivian Amazon indigenous groups

A study published in the journal ‘Alzheimer’s & Dementia’ has found that dementia prevalence among the Tsimané and Mosetén indigenous groups in the Bolivian Amazon is exceptionally low, at approximately 1% to 2%. This is significantly lower than the roughly 8.5% prevalence observed in older Brazilian populations.

Researchers from the United States followed 730 adults from these communities over a five-year period. While the incidence rate was calculated at 7.4 cases per thousand person-years, the study revealed a concerning trend: individuals who developed dementia faced a mortality risk six times higher than those with normal cognition. This high mortality rate helps explain the low overall prevalence of the condition in these communities, as those diagnosed do not survive as long as those in industrialized societies, where the mortality increase associated with dementia is estimated at two to three times.

The Tsimané maintain a subsistence lifestyle involving hunting, fishing, and gathering, while the Mosetén show higher levels of integration with broader Bolivian society. Scientists are investigating whether these distinct daily routines and environmental factors influence these health outcomes.