Distinct educational level effect on general cognition between two geopolitical regions

Abstract

Introduction: Low- and middle-income countries usually have larger heterogeneity in education quality, a reflection of complex socioeconomic and cultural diversity. Education is known to impact neuropsychological assessment, and tests norms usually are grouped by years of education. Disparities in education effect on cognition might result in diagnosis errors. Objective: We aimed to compare the effect of education on general cognition in older adults from two Brazilian geopolitical regions. Method: 125 northeast (NE) healthy older adults (mean age=70.08±7.76 years, 66% female) and 115 southeast (SE) (mean age=72.39±8.09 years, 76% female), with equal education range (1-19), mean and variance (p=0.52). All participants performed the Dementia Rating Scale (DRS-Mattis), and the residual variance (regressed on age) was used. We divided education into three achieved levels: primary (1-4 years), elementary-to-high school (5-11 years) and undergraduate (equal and higher than 12 years). Result: We found a distinct effect of education according to geopolitical region for episodic memory and visioconstruction ability. Comparing simple effect sizes for educational level by region, there is a medium effect (r=0.30) for the primary level between regions, having the NE group a significantly lower  performance. Conclusion: Education effect on general cognition is similar for both regions, but older adults with primary level have significant distinct performance depending on their region. Primary education inequality might be related to other socioeconomic factors presented across country regions. We highlight the necessity of representative samples in heterogeneous countries as Brazil, in order to avoid clinical assessment errors when using restrict national norms.