Objectives: The primary aim of this study is to assess the relationship between different aspects of physical activity (PA) and dementia occurrence in older adults from Brazil.

Methods: It is a secondary analysis of the first wave data derived from the ELSI-Brazil study, a longitudinal study of aging in Brazil with a representative sample of Brazilians aged 50 years and older (n = 9,412). We employed two distinct approaches to assess PA. First, participants’ levels of PA were classified in low, moderate and high based on their reported physical exertion over the preceding seven days at the time of interview. Also, PA was classified as sufficient or not sufficient, according to the World Health Organization (WHO) recommendation. Dementia was defined as those who were 60 years and older, had a cognitive performance ≤1.5 z-score compared to a sub- sample defined as control-group, and also had an impairment in instrumental activity of daily living. Logistic regression was used to estimate the association between physical activity and dementia (crude and adjusted for age, gender, schooling, marital status, smoking and alcoholconsumption).

Results: After excluding those younger than 60 years old and had missing data to any of the variables analyzed, our sample was composed by 4,994 individuals (table 1), with a mean age of 69.7 (SD = 7 .5), 4.7 years of schooling (SD = 4.3) and 214 (4.1%) classified as living with dementia. We also found that higher levels of PA were associated with lower occurrences of dementia (table 2) (moderate OR 0.57 95% CI 0.37 –0 .90, p < 0.05; high OR 0.32 95% CI 0.19 –0.56, p < 0.001). Also, practicing the level of PA recommended by WHO had an inverse association with dementia (table 3) (OR 0.49 95% CI 0.30 – 0.79, p < 0.05).

Conclusions: The main limitation of our study is its cross-sectional nature. Therefore, we cannot determine the direction of relationships between variables. Our findings show a significant inverse association between levels of PA and dementia occurrence. Additionally, adherence to the WHO’s recommendation for PA also showed a significant inverse association with dementia occurrence. These results underscore the importance of promoting regular physical activity as a potential preventive measure against dementia among older Brazilian adults.