Association of inflammatory biomarkers with depressive symptoms and cognitive decline in a community-dwelling healthy older sample: A 3-year follow-up study

Background: The relationship between the pathophysiology of dementia and neuroinflammation is well-known. The number of reports stating that depression is a risk factor for dementia has recently been increasing. These epidemiological findings suggest the possibility that both depression and dementia have common pathophysiological backgrounds of neuroinflammation. Methods: The sample consists of 64 non demented cominunity-dvvelling older participants aged 65 years or over Participants were assessed at baseline (2004-2006) and 3 years later (2007-2009). Plasma concentration of markers of inflammation (interleukins (IL) 113, IL 2, IL 6, soluble interleukin-2 receptor (sIL-2R), soluble interleukin-6 receptor (sIL-6R), high sensitivity C-reactive protein (hsCRP) and tumor necrosis factor (TNE-alpha) were measured at baseline. Depression symptoms were assessed with the Beck Depression Inventory (BEN) and cognitive decline was assessed with the Mini-Mental State Examination (MMSE), Frontal Assessment Battery (FAB) and Clock Drawing Test (CDT) at baseline and follow-up. All analyses were adjusted for age, gender and years of education. Results: In the cross-sectional analysis, the present study found soluble IL-2 receptor (sIL-2R) to be associated only with the MMSE score at baseline in men. In the longitudinal analysis, none of our inflammatory biomarkers were associated with either depressive symptoms or cognitive decline. Limitations: The present study consists of small number of participants and body mass index (BNB) scores were not obtained. Conclusions: Our findings suggest that sIL-2R is associated with current cognitive function in men. None of our inflammatory markers predicted future depressive state or cognitive decline in our community-dwelling healthy older sample. (C) 2014 Elsevier B.V. All rights reserved