Associations Between Inflammation and Cognitive Function in African Americans and European Americans

Abstract

OBJECTIVES Elucidating associations of specific inflammatory biomarkers with cognitive function in African Americans (AA) and European Americans (EA) with prevalent vascular risk factors could identify vascular-mediated effects on cognitive impairment. DESIGN Cross-sectional analysis using Generalized Estimating Equations to account for familial clustering; standardized β-coefficients, adjusted for age, sex, and education are reported. SETTING A community cohort study in Jackson, MS and Rochester, MN. PARTICIPANTS Genetic Epidemiology Network of Arteriopathy (GENOA)-Genetics of Microangiopathic Brain Injury (GMBI) Study. MEASUREMENTS We examined associations between inflammation [high-sensitivity C-reactive protein (CRP), interleukin (IL)-6, soluble tumor necrosis factor receptors 1 and 2 (sTNFR1, sTNFR2)] and cognitive function measures [global (G), processing speed (PS), language (L), memory (M), and executive function (EF)] in AA and EA (N=1965; age 26–95y, 64% women, 52% AA, 75% hypertensive). RESULTS In AA, higher sTNFR2 was associated with poorer cognition across all domains (G: −0.11, p=.009; PS: −0.11, p<.001; L: −0.08, p=.002; M: −0.09, p=.008; EF: −0.07, p=.032); sTNFR1 was associated with poorer PS (−0.08, p<.001) and with EF (−0.08, p=.008); higher CRP was associated with lower PS (−0.04, p=.024), and higher IL6 was associated with poorer EF (−0.07, p=.019). In EA, only higher sTNFR1 was associated with poorer PS (−0.05, p=.007). We did not find support for associations between cognition and sTNFR2, CRP or IL6 in EA. CONCLUSION In a population with heightened vascular risk, adverse associations between inflammation and cognitive function were especially apparent in AA, primarily involving markers of TNFα activity.

Role of inflammatory cytokines in depression: Focus on interleukin-1β

“…Similarly, depression has been associated with systemic diseases involving induction of a pro-inflammatory state or upregulation of inflammatory markers. For example, levels of IL-6 have been found to increase with age (25) and be associated with cognitive wellbeing (26). In addition, depression caused an increase in fatty lesions in arteries in a mouse model, providing a potential link between psychological stress and vascular diseases (27).…”

Response to Mehmet I. Naharci

“…To the Editor : In Dr. Naharci's thoughtful comments on our recent article in this journal, he suggested that frailty, depression, and medications for hypertension and diabetes mellitus could be important considerations in the relationship between inflammation and cognition. Dr. Naharci correctly noted that a significant proportion of the GENOA cohort were taking medications for hypertension and diabetes; 495 (18%) were taking medications for diabetes mellitus and 1,902 (70%) for hypertension.…”

Associations Between Inflammation and Cognitive Function in African Americans and European Americans

“…To the Editor : In a recent issue of the Journal of the American Geriatrics Society , Windham and colleagues reported interesting and valuable findings regarding the role of inflammation in cognitive dysfunction according to race . Although growing evidence indicates such a link, the important aspect of this study is that inflammatory markers (high‐sensitivity C‐reactive protein (CRP), interleukin (IL)‐6, soluble tumor necrosis factor (TNF) receptors) are differentially associated with cognitive domains in African Americans and European Americans with vascular risk factors . Several points merit discussion.…”

“…As shown in Table 1, hypertension was present in nearly three quarters of participants, and one in five participants had diabetes mellitus, indicating that a significant proportion of the sample was receiving medications for two comorbidities. It has been reported that inflammation markers improved with antihypertensive and antidiabetic agents …”