Is there a relationship between low-grade systemic inflammation and cognition in healthy people aged 60-75 years?

Although inflammation has been associated with cognitive impairment in dementia, less is known about its role in the cognition of middle to older aged healthy people. This study utilised baseline data from the Australian Research Council Longevity Intervention (ARCLI) trial to investigate the relationship between markers of systemic inflammation (TNF-α, IL-6, IL-1β, INF-γ, IL-2, IL-4, IL-10 and hsCRP) and cognitive function in 286 healthy volunteers aged 60-75 years. We assessed cognitive functioning across domains including attention, speed of memory, working memory and episodic memory using the Cognitive Drug Research test battery. Only IFN-γ was related to cognitive function, being associated with greater odds of having low continuity of attention (log2 IFN-γ OR, 1.46; 95 % CI, 1.18-1.85). The relationship between episodic memory, speed of memory and inflammation varied with BMI. In high BMI participants, increased inflammation was associated with worse cognitive function, while this association was reversed in those with low BMI. Outside of the influence of IFN-γ on attention, low-grade systemic inflammation was not robustly associated with cognitive function in this sample of middle to older aged healthy people. Further research is required to understand the role of BMI in the intersection of inflammation and cognitive function.