The North and Northeast regions of Brazil had higher predicted probabilities of elevated serum immunological biomarker levels while the Central-West region had lower levels, suggesting differences in 'immunobiography' that may result from distinct environmental, socioeconomic, and infectious exposures throughout life.
Key Findings
Results
The North and Northeast Brazilian regions showed higher predicted probabilities of elevated serum immunological biomarker levels compared to other regions.
Serological samples from 2,111 participants aged ≥50 years collected at the baseline (2015/2016) of ELSI-Brazil were analyzed.
Geographic regions (North, Northeast, Central-West, Southeast, and South) were the exposure of interest.
Predicted probabilities of biomarker concentrations in each tertile were estimated using multinomial logistic regression models adjusted for confounders.
The North and Northeast regions had higher serum levels, suggesting differences in immunobiography.
Results
The Central-West region of Brazil showed lower predicted probabilities of elevated serum immunological biomarker levels compared to other regions.
The Central-West Region had lower serum immunological biomarker levels compared to North and Northeast regions.
This finding was derived from multinomial logistic regression models adjusted for potential confounders.
Confounders included age, sex, educational level, area of residence, alcohol and tobacco consumption, physical activity, and self-reported diagnoses of hypertension, diabetes, asthma, arthritis, and cancer.
Discussion
Regional differences in immunological biomarker profiles among older Brazilian adults suggest variation in 'immunobiography' across the country.
The authors attribute the observed regional differences to potentially distinct environmental, socioeconomic, and infectious exposures throughout life.
The concept of 'immunobiography' refers to the cumulative history of immune exposures shaping the current immunological profile.
The study analyzed participants aged ≥50 years (n=2,111) across five Brazilian geographic regions.
The reasons for these regional differences 'have not yet been elucidated and need to be investigated in further studies.'
Methods
The study used multinomial logistic regression to estimate predicted probabilities of immunological biomarker concentrations falling within each tertile of distribution by geographic region.
Outcome was defined as tertiles of biomarker concentration distribution.
Models were adjusted for age, sex, educational level, area of residence, alcohol and tobacco consumption, physical activity, and self-reported medical diagnoses of hypertension, diabetes, asthma, arthritis, and cancer.
The sample consisted of 2,111 participants aged ≥50 years from the ELSI-Brazil cohort baseline collected in 2015/2016.
The five Brazilian geographic regions served as the primary exposure of interest.
Background
Immunosenescence and inflammaging — age-related increases in inflammatory biomarkers — are the biological framework underpinning this study of regional variation in immune profiles among older Brazilians.
Immunosenescence refers to changes in the immune system with aging, including the increase in inflammatory biomarkers.
This phenomenon is known as 'inflammaging' and is related to the emergence of diseases associated with aging.
The study aimed to describe the distribution of immunological biomarkers in the five Brazilian regions in this context.
Participants were ≥50 years of age, a population subject to immunosenescent processes.
What This Means
This research suggests that older adults (aged 50 and above) living in different regions of Brazil have meaningfully different immune system profiles, as measured by levels of immunological biomarkers in their blood. Using data from over 2,000 participants in a large Brazilian study (ELSI-Brazil), researchers found that people in the North and Northeast regions were more likely to have higher levels of these immune markers, while those in the Central-West region were more likely to have lower levels. These differences held even after accounting for factors like age, sex, education, lifestyle habits, and chronic diseases.
The researchers interpret these differences through the concept of 'immunobiography' — the idea that a person's immune system is shaped over their lifetime by the infections, environmental conditions, and socioeconomic circumstances they have been exposed to. Brazil's regions differ substantially in climate, infectious disease burden, and socioeconomic development, all of which could help explain why immune profiles vary so much across the country. However, the study notes that the precise reasons for these differences remain unclear and require further investigation.
This research matters because elevated inflammatory markers in older adults are linked to a range of age-related diseases, and understanding why some populations have higher levels could eventually help explain regional differences in health outcomes among older Brazilians. It highlights that immune aging is not uniform across a large, diverse country and that geography — and the life experiences tied to place — may play an important role in shaping how the immune system ages.
Lima-Silva M, Mambrini J, Torres K, Martins-Filho O, Teixeira-Carvalho A, Lima-Costa M, et al.. (2026). [Evaluation of the immunological profile of older adults according to Brazilian regions: results of ELSI-Brazil].. Cadernos de saude publica. https://doi.org/10.1590/0102-311XPT172124