The Role of Allostatic Load in Cognitive Impairment and Dementia in Latin America Population

BACKGROUND: Latin America (LA) experiences disparities driven by social determinants of health and low socioeconomic status, which increase the risk of dementia. These adverse factors may contribute to dementia through allostasis, the body's adaptive response to stressors. Chronic stressors can lead to allostatic overload, disrupting physiological systems and increasing the risk of diseases like dementia. While chronic stress is linked to cognitive decline, further research is needed to understand cumulative effects and develop an allostatic index (ALI) specific to the LA population. METHOD: We analyzed data from 8,044 participants across four LA cohorts: Chilean National Health Survey (Chile), GERO (Chile), ReDLat, and Costa Rica, including individuals with and without cognitive impairment or dementia. ALI was calculated using metabolic, cardiovascular, immune, neuroendocrine, and anthropometric biomarkers. Specific indices were developed for each cohort, considering cutoff values, percentiles, and risk quartiles. Logistic regression models examined associations between ALI and cognitive status, assessed with the Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and Clinical Dementia Rating (CDR). RESULT: Higher ALI was associated with increased risk of cognitive impairment and dementia. In Costa Rica, ALI was significantly associated with cognitive impairment (OR = 1.048; p =  0.021). In the ReDLat cohort, higher ALI correlated with worse clinical cognitive status (OR = 1.068; p =  0.031). In the GERO Chile cohort, ALI showed significant impact (OR = 1.17; p =  0.04). In the CNHS, higher ALI notably increased cognitive impairment risk (OR = 7.15; p =  0.015). CONCLUSION: ALI is a relevant marker for identifying cognitive impairment and understanding its relationship with chronic stress. Monitoring biomarkers such as systolic blood pressure and waist-to-height ratio can improve the characterization of dementia in LA populations. These findings highlight the importance of addressing chronic stress and its biological impacts in diverse settings.