The potential for dementia prevention in Brazil: a population attributable fraction calculation for 14 modifiable risk factors

Abstract

Background: The Lancet Commission on dementia prevention, intervention, and care 2024 updated the list of modifiable risk factors to include 14 factors. The potential for dementia prevention seems to be greater in low- and middle-income countries (LMIC) due to the higher prevalence of these factors. This study aims to provide the first LMIC figure for the potential for dementia prevention in Brazil attributed to 14 modifiable risk factors.

Methods: Data was retrieved from 9949 participants aged 50 years or older from the nationally representative second wave of the Brazilian Longitudinal Study of Aging (ELSI-Brazil) conducted between 2019 and 2021. The prevalence of modifiable risk factors was estimated, and principal component analysis was used to account for factor communalities. Overall and individual population attributable fractions (PAF) were calculated using relative risks from the 2024 Lancet Commission report. Stratified analyses by sex, race, and Brazilian macro regions were performed to assess disparities in dementia risk.

Findings: The overall PAF for the 14 modifiable risk factors was 59.5% (95% CI = 58.5-60.5). The three risk factors with the highest PAFs were less education (9.5%, 95% CI = 8.9-10.1), untreated visual loss (9.2%, 95% CI = 8.6-9.8), and midlife depression (6.3%, 95% CI = 5.8-6.8). The overall PAF was similar across race and region but was higher among women (61.1%, 95% CI = 59.9-62.4) compared to men (58.2%, 95% CI = 56.7-59.8).

Interpretation: Almost 60% of dementia cases in Brazil could potentially be prevented by addressing 14 modifiable risk factors. Public health strategies could further reduce the dementia burden in Brazil.

Funding: CKS, PC, and CPF received productivity fellowships from the National Council for Scientific and Technological Development (CNPq). ELSI-Brazil was supported by the Brazilian Ministry of Health: DECIT/SCTIE (Grants: 404965/2012-1 and TED 28/2017); COPID/DECIV/SAPS (Grants: 20836, 22566, 23700, 25560, 25552, and 27510).