Year: 2019
Type: article
Abstract: Low socioeconomic status (SES) has been linked to a variety of poor lifestyle factors and greater risk of developing Alzheimer's dementia (AD). Recent research suggests SES may be related to alterations in brain health, however, extant studies have not investigated modifiable risk factors that may contribute to the observed associations. The aims of this study were to i) investigate whether SES is associated with brain volume in AD related regions, and if so, ii) determine whether this relationship is mediated by modifiable factors that are known to associate with risk of AD. We studied 645 biracial (41% black) participants (mean age 55.3±3.5) from the Coronary Artery Risk Development in Young Adults (CARDIA) study who underwent brain magnetic resonance imaging. SES was operationalized as a composite measure of annual income (1=≤49,999; 2=50,000-99,999; 3=≥100,000) and years of education (1=≤12; 2=13-16; 3=≥17). Grey matter volume was estimated within the insular cortex, thalamus, cingulate, frontal, inferior parietal and lateral temporal cortex. These regions were vulnerable to age-related atrophy captured with the Spatial Pattern of Atrophy for Recognition of Brain Aging (SPARE-BA) index. Risk factors of interest included hypertension, obesity, depression, cognitive activity (e.g. book/newspaper reading), physical activity, smoking, diet, alcohol consumption and diabetes. Multiple linear regression tested the association between SES and brain volume. Sobel mediation analyses determined if this association was mediated by modifiable risk factors. All models were age, sex, and race adjusted. Aim i) regression analysis revealed SES was positively associated with brain volume (Figure 1; β=.118 SE=.039; p=.002). Aim ii) from the nine risk factors investigated, smoking and depression were identified as two potential mediators due to their significant relationships with SES and brain volume (all p<.05). A Sobel mediation analysis determined smoking significantly mediated the relationship between SES and brain volume (Figure 2; p=.016). With respect to brain volume, smoking accounted for a significant amount of variance (β=−.116 SE=.065; p=.01) that was previously attributed to SES.
Source: Alzheimer s & Dementia
Institutions: National Institutes of Health, University of Wisconsin–Madison, National Institute on Aging, San Francisco VA Medical Center, University of California, San Francisco, University of California San Francisco Medical Center, San Francisco VA Health Care System, Kaiser Permanente, Kaiser Permanente Northern California, University of Pennsylvania, Universitätsmedizin Greifswald, Universität Greifswald
Language: English
Subfield: Psychiatry and Mental health
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W4252144892