Social and health disparities drive brain aging in Latin America

Research reveals Brazil’s unique risk factors, with education as the top predictor of cognitive decline, unlike other Latin American nations where mental health plays a larger role.

​​​​​​​Study: Social and health disparities associated with healthy brain ageing in Brazil and in other Latin American countries. Image Credit: Motortion Films/Shutterstock.com

In a recent study published in The Lancet Global Health, researchers identified the factors associated with healthy brain aging in people from countries in Latin America, including Brazil, Colombia, Chile, Uruguay, and Ecuador.

Their findings highlight that inequalities in health and social factors are more likely to explain differences in functional ability and cognition than demographic characteristics. For Brazil, in particular, researchers found that education was a primary factor affecting cognitive outcomes.

Background

Encouraging healthy brain aging is a priority for countries worldwide so that people can live fulfilling lives at any age. Brain health is generally assessed by examining functional and cognitive abilities.

It is influenced by gender, age, and social factors such as support systems, educational attainment, and socioeconomic status, as well as lifestyle factors, health conditions, and mental health.

Researchers have found evidence of regional differences in risk factors associated with brain aging. In Latin America, the contribution of various risk factors varies among countries, and research suggests that educational and socioeconomic disparities may be more influential than demographic characteristics such as sex or age.

Brazil, the region’s largest economy, presents an important case study, as it has significant socioeconomic inequalities related to access to services.

An estimated 75% of the country’s population is reliant on health services provided by the government. Though free healthcare is available, its quality is uneven, which has led to increases in preventable illnesses.

The country also faces high rates of dementia. Hypertension, hearing loss, and physical inactivity have been identified as risk factors by previous studies.

The demographic makeup of Brazil, including Indigenous communities and people with Asian, European, and African ancestry, allowed researchers to study the impact of varied health-related and social characteristics on brain aging.

About the study

Researchers used machine learning techniques to identify risk factors for functional and cognitive decline in a large study comprising cohorts from Brazil, Colombia, Chile, Uruguay, and Ecuador.

They hypothesized that, as seen in other Latin American nations, health and social disparity would contribute more to brain aging risk than demographic characteristics. However, they also predicted that Brazil’s diverse background could give rise to unique features.

A total of 41,092 individuals with an average age of 70.8 were included in the sample. Of these, 1301 people were from Chile (aged 71.8 on average), 1450 were from Uruguay (70.8 on average), 5235 were from Ecuador (aged 70.1 on average), and 9412 were from Brazil (aged 63.5 on average).

Based on classifications by the World Bank, Uruguay and Chile were categorized as high-income countries, and Ecuador, Colombia, and Brazil were classified as low- and middle-income countries.

To assess cognition, researchers used results from screening tests designed to check for cognitive impairment as well as skills like temporal orientation, verbal fluency, and word retrieval. Functional ability was assessed by examining whether the participants could perform daily activities related to mobility, grooming, and dressing.

The social predictors in the models included education, socioeconomic status, social isolation, sex, and age.

Meanwhile, health-related characteristics included symptoms of mental health (anxiety and depression), smoking, alcohol consumption, physical inactivity, falls, heart disease, hypertension, and diabetes.

Findings

On average, participants from Brazil were younger and had higher educational attainment than those from other countries. However, physical inactivity was also lowest in this country, and symptoms of anxiety and depression were most pronounced.

Smoking rates were highest in Ecuador, followed by Uruguay. Hypertension rates were similar across all five nations.

Brazil showed the lowest scores for both functional and cognitive abilities. For cognition, the most important contributors identified by the model were educational attainment, symptoms of mental health, physical inactivity, smoking, socioeconomic status, and age.

For functional ability, the most important factors were symptoms of mental health, falls, heart disease, physical activity, diabetes, alcohol consumption, hypertension, education, and isolation.

Within Brazil, cognitive decline was most pronounced in the northern region compared to the southeast, south, and central-western areas of the country. Living in the northeast region was identified as a risk factor for functional ability.

Conclusions

Overall, symptoms of mental health remained a significant factor for functional and cognitive decline across all the countries studied. However, socioeconomic status, physical activity, and education were important predictors. Smoking and alcohol consumption also had a moderate impact.

While these findings are indicative, they were based on self-reported data, which can be biased and included limited screening tools for functional and cognitive ability.

Interventions to promote healthy brain aging should be tailored to the region and consider social and health-related disparities.