Community Socioeconomic Disadvantage in Midlife Relates to Cortical Morphology via Neuroendocrine and Cardiometabolic Pathways

Abstract

Residing in communities of socioeconomic disadvantage confers risk for chronic diseases and cognitive aging, as well as risk for biological factors that negatively affect brain morphology. The present study tested whether community disadvantage negatively associates with brain morphology via 2 biological factors encompassing cardiometabolic disease risk and neuroendocrine function. Participants were 448 midlife adults aged 30-54 years (236 women) who underwent structural neuroimaging to assess cortical and subcortical brain tissue morphology. Community disadvantage was indexed by US Census data geocoded to participants' residential addresses. Cardiometabolic risk was indexed by measurements of adiposity, blood pressure, glucose, insulin, and lipids. Neuroendocrine function was indexed from salivary cortisol measurements taken over 3 days, from which we computed the cortisol awakening response, area-under-the-curve, and diurnal cortisol decline. Community disadvantage was associated with reduced cortical tissue volume, cortical surface area, and cortical thickness, but not subcortical morphology. Moreover, increased cardiometabolic risk and a flatter (dysregulated) diurnal cortisol decline mediated the associations of community disadvantage and cortical gray matter volume. These effects were independent of age, sex, and individual-level socioeconomic position. The adverse risks of residing in a disadvantaged community may extend to the cerebral cortex via cardiometabolic and neuroendocrine pathways.

Allostatic load and reduced cortical thickness in schizophrenia

“…Previous studies have demonstrated a link between obesity and reduced cortical thickness, an association suspected to be mediated by low grade inflammation (Veit et al, 2014). Other evidence suggests that relative socioeconomic disadvantage is associated with alterations in cortical morphology that are mediated by greater inflammation (Gianaros et al, 2015; Krishnadas et al, 2013). Indices of allostatic load, which incorporate measures of both adiposity and inflammation, may thus have utility as an integrative marker of risk factors for changes in brain morphology in aging and stress-related illnesses.…”

Cognitive and brain development is independently influenced by socioeconomic status and polygenic scores for educational attainment

“…Neither SES nor EduYears-PGS were significantly related to average cortical thickness at age 14 or to the thinning over adolescence. Furthermore, there were no significant regional associations (at 14 or from [14][15][16][17][18][19] for cortical thickness from either SES or EduYears-PGS, regardless of global correction.…”

“…The distinction is important because it tells us about the potential mechanisms in play, has functional consequences for the individual and could have implications for remedial interventions. Therefore, we tested for distinct global and regional associations -a practice still ignored in the literature 4,5,8 , with the exception of only one known study to date 16 . The latter, however, did not control for any genetic component of SES.…”

Socioeconomic disadvantage and altered corticostriatal circuitry in urban youth

“…Our measure of community SED was estimated based on US Census data geocoded to participants’ zip codes. This approach is consistent with the few published studies examining community SED and brain organization (Gianaros et al, ; Krishnadas et al, ). As others have noted, however, there is no best approach for measuring within‐household or community‐level SED (Farah, ; Ursache & Noble, ).…”