Inflammation and cognitive functioning in African Americans and Caucasians

• Type of Material: Article
• Authors: Felicia Goldstein, Emory University; Liping Zhao, Emory University; Nelson Steenland, Emory University; Allan Levey, Emory University
• Language: English
• Date: 2015-09-01
• Publisher: Wiley
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2014 John Wiley & Sons, Ltd.
• Final Published Version (URL): http://dx.doi.org/10.1002/gps.4238
• Title of Journal or Parent Work: International Journal of Geriatric Psychiatry
• ISSN: 0885-6230
• Volume: 30
• Issue: 9
• Start Page: 934
• End Page: 941
• Grant/Funding Information: National Center for Advancing Translational Sciences of the National Institutes of Health. Grant Number: UL1 TR000454; Emory Alzheimer's Disease Research Center. Grant Number: NIH-NIA 5 P50 AG025688
• Keywords: inflammation; PREDICTIVE HEALTH; OLDER-ADULTS; IMPAIRMENT; Geriatrics & Gerontology; C-REACTIVE PROTEIN; PERFORMANCE; African Americans; cytokines; ALZHEIMERS-DISEASE; ASSOCIATION; BRAIN VOLUME; Gerontology; cognition; Science & Technology; MARKERS; race; Life Sciences & Biomedicine; POPULATION; Psychiatry
• Research Categories: Health Sciences, Epidemiology; Biology, Neuroscience; Gerontology

Abstract

Objective: To examine associations between inflammation and cognitive performance in African Americans and Caucasians. Methods: The sample included 59 African Americans and 219 Caucasians ≥50years old who had a baseline visit at the Emory/Georgia Tech Center for Health Discovery and Well Being. Peripheral levels of inflammation (interleukin-6, interleukin-8, C-reactive protein, and tumor necrosis factor-α) were examined in relation to performance on tests of visual processing (Identify the Odd Pattern), attention (Digit Span Forward), visuomotor set shifting (Digit Symbol Substitution), verbal set shifting (Digit Span Backwards), and memory (Recall a Pattern). Results: Multiple regression models adjusting for potential demographic and vascular/metabolic confounders were conducted, with markers of inflammation included as either continuous or categorical (quartiles) variables. There were significant interactions between IL-8 and race for the Recall a Pattern (p=.006) and the Digit Symbol Substitution (p=.014) tests. Race-specific analyses (using a continuous variable for IL-8) demonstrated slower response times on the Recall a Pattern and Digit Symbol Substitution tests for African Americans but not for Caucasians. Categorical analyses among African Americans indicated that all of the top three quartiles of IL-8 were associated with slower reaction times on the Recall a Pattern test compared to the lowest quartile, while for Digit Symbol, the highest quartile of IL-8 was associated with the slowest cognitive performance. Conclusions: These preliminary findings suggest a stronger association between IL-8 and cognitive performance in African Americans than Caucasians. This relationship should be further examined in larger samples that are followed over time.