PULLMAN, Washington – No billionaire lives among the Tsimane people of Bolivia, although some are a little better off than others. These subsistence communities on the edge of the Amazon also have fewer chronic health problems linked to the type of dramatic economic disparity found in industrialized Western societies.
For a study in the journal eLife, a research team led by Aaron Blackwell of Washington State University and Adrian Jaeggi of the University of Zurich followed 13 different health variables in 40 Tsimane communities, analyzing them in relation to the wealth of each person and the degree of inequality in each community. . While some have speculated that the impacts of health inequalities are universal, researchers have found only two strongly associated results: higher blood pressure and respiratory disease.
“The link between inequalities and health is not as simple as what you would see in an industrialized population. We’ve had a lot of mixed results, ”said Blackwell, associate professor of anthropology at the WSU. “These results suggest that at this scale, inequality is not at the level that causes health problems. Instead, it may be the extreme inequality in many modern environments that causes health issues, as it is unlike any inequality we have ever had in our evolutionary history. “
Anthropologists are particularly interested in the study of the Tsimane because their traditional way of life more closely resembles the conditions in which humans lived for many centuries before the modern era. The Tsimane eat very little processed food – instead, they feed, hunt, fish and farm. They also exercise a lot as part of their daily activities and have few health problems associated with modern societies like obesity, diabetes, and heart disease. They do not have easy access to modern health care and therefore have to deal with parasites and many respiratory ailments ranging from the common cold to pneumonia.
Beginning in 2001, a team of health care workers and researchers travel to these communities each year to provide care and collect data as part of a larger project on the health and life history of Tsimane. For this study, Blackwell, Jaeggi and their colleagues were able to analyze data at different points in time, up to 2015.
Tsimane communities are smaller and more egalitarian than most industrialized societies, but some communities have more inequalities than others. Researchers found that for several health variables, including body mass index, gastrointestinal upset, and depression, there was no clear link to the disparity.
However, in communities with high inequality, many people had higher blood pressure, whether at the top or bottom of the economic pecking order, compared to their peers in less stratified communities. The highest blood pressure was seen in poor Tsimane men no matter where they lived.
“Basically it’s wrong to be poor, but it’s also wrong to be poorer,” Jaeggi said. “If you feel like you’re worse than other people, it’s stressful. In western industrialized societies, it is associated with many negative health consequences like high blood pressure, cardiovascular problems and infectious diseases, as COVID-19 has shown. In Tsimane communities, we found negative effects of living in a more unequal community, but it certainly wasn’t on all outcomes, so it seems less of a universal model.
This study was conducted before the pandemic, so the impacts of COVID-19 were not included, but researchers found a link with an increased risk of respiratory illnesses like influenza and pneumonia to inequalities. The authors said it was not clear what the exact mechanisms of this connection might be, as there was no clear link with stress, unlike in Western societies.
Blackwell also noted that although an increase in high blood pressure was seen in more unequal communities, it had not developed into worse conditions such as hypertension and cardiovascular disease which is more prevalent in industrialized societies.
“I think this study tells us that there are some of the reasons why inequality is bad for us, even in relatively egalitarian societies without huge economic differences,” he said. “So maybe if we want to improve health for everyone, then trying to reduce inequalities is one way to get there.”