Risk and protective factors for dementia: epidemiological evidence and windows of opportunity

Abstract

AbstractBackgroundMost people with dementia already live in low‐ to middle‐income countries (LMIC). However, most evidence regarding dementia prevention comes from high‐income countries that have different socioeconomic status (SES) and risk factors prevalence than LMIC. In this session, we will present results on risk and protective factors for dementia from the Longitudinal Study of Adult Health (ELSA‐Brasil), the Brazilian Longitudinal Study of Aging (ELSI‐Brazil), and the Brazilian Biobank for Aging Studies (BAS).MethodThe ELSA‐Brasil follows 15,105 public servants since 2008‐10. The ELSI‐Brazil is a nationally representative study with 9,412 adults aged 50 years and older, who were enrolled in 2015‐16. The BAS is a neuropathology study that started in 2004 and is the largest brain bank in Latin America with a collection of 1,441 brains. The focus of this presentation will be on the associations of education, SES, and cardiovascular factors with dementia using data from these three studies.ResultIn the BAS, 77% of the sample has less than 5 years of education and 56% unskilled occupations. Compared to the group without education, those with formal education had better cognitive performance (1‐4 years: 𝛽 = ‐0.99, 95%CI = –1.85; –0.14, p = 0.02; ≥5 years: = –1.42, 95% CI = –2.47; –0.38, p = 0.008). On the other hand, occupation complexity and demands were unrelated to cognition. Similarly, we showed that education and early‐life SES were the main contributors to cognitive performance in the ELSA‐Brasil, while later SES had a lower influence on cognitive scores. Cardiovascular factors are also important contributors to brain health. Ideal vascular health was related to better cognitive function in the ELSA‐Brasil. Participants with intermediate (β = 0.064, 95%CI = 0.033; 0.096) and optimal health (β = 0.108, 95%CI = 0.052; 0.164) had better cognitive z‐scores. Moreover, carotid artery atherosclerosis evaluated by morphometric measurements was related to cognitive impairment in BAS and with cognitive decline in the ELSA‐Brasil after 8 years of follow‐up (β = ‐0.028, 95%CI = ‐0.036; ‐0.020, p<0.001). Finally, hypertension was related to worse cognition (β = ‐0.09; 95%CI = ‐0.15, ‐0.04; p = 0.001) in ELSI‐Brazil, mainly in non‐frail participants.ConclusionStudies from LMIC regarding dementia risk factors are essential to implement tailored public policies for dementia primary prevention.