Association of neighborhood‐level socioeconomic advantage with cognition and dementia risk factors in an Australian cohort

Abstract

AbstractBackgroundResiding in areas of low socioeconomic advantage is associated with increased risk of dementia1 and associated brain pathology2,3. Given the long and insidious course of dementia pathologies, it is critical to establish the effect of ‘exposomic’ risk factors in midlife and to understand which groups of people are particularly vulnerable. Therefore, the objective of this study was to examine whether cognitive performance or dementia risk factors differed according to neighborhood‐level socioeconomic advantage in cognitively normal middle‐aged people.MethodsOur sample comprised 4798 participants from the Healthy Brain Project, an online cohort of community‐dwelling Australians aged 40‐70 years. Socioeconomic advantage was computed by matching participants’ residential address to the Australian Bureau of Statistics’ Index of Relative Socioeconomic Advantage and Disadvantage (IRSAD), assigning each participant a decile score (10 being the most advantaged). Scores were related to dementia risk estimated using the CAIDE dementia risk score and cognitive performance measured with the Cogstate Brief Battery (CBB) in linear regression models.ResultsOf the 4798 participants (mean age±SD 56±7 years, 26% male), 2762 (58%) were classified as living within an area of high neighbourhood socioeconomic advantage (IRSAD scores ≥ 8th decile), 1296 resided in rural or regional areas (27%), and 984 identified as “non‐European” (21%). Each decile unit increase in neighborhood socioeconomic advantage was associated with a lower CAIDE dementia risk score (β±SE= ‐0.088±0.024, p <0.001), following adjustments for race and rurality, and with better memory performance (β±SE= 0.084±0.024, p <0.001), following adjustments for age, sex, race, education, and rurality. An interaction was observed with differences in memory performance between levels of neighborhood advantage (comparing scores above and below the 8th decile) being larger at older ages and in people with higher dementia risk scores (Figure 1). There was no association between neighborhood‐level advantage and attention.ConclusionsIn a middle‐aged Australian cohort, higher neighborhood‐level socioeconomic advantage was associated with superior memory and lower dementia risk scores. Efforts to lower dementia risk factors, particularly in relation to reducing the negative impacts of disadvantage, are needed to curtail the growing burden of dementia.