Peripheral inflammation and executive function among community samples across the lifespan: A systematic review and meta-analysis.
Higher levels of peripheral inflammatory markers are proposed to disrupt cognitive processes; however, the extent to which this relationship applies to executive functions, specifically, has yet to be systematically evaluated. The current meta-analysis synthesizes all available literature measuring the association between peripheral inflammation and executive functions among community individuals across the lifespan. This systematic review searched Web of Science, PubMed, and PsycINFO for published and unpublished studies, in the English language, that assessed the association between markers of peripheral inflammation and self-report and behavioral measures of executive function. In addition to methodological and demographic information, correlation/beta coefficients were extracted from included studies to quantify the association between inflammation and executive functions. This review included 58 studies, 41 of which were included in the random-effects meta-analysis (N = 255,539). Among community individuals, higher levels of CRP and IL-6 were associated with poorer executive functioning. These results did not differ when models accounted for potential confounding variables. Meta-regressions revealed that the relationship between inflammatory biomarkers and executive function did not differ as a function of age, adiposity, or percentage of the sample who identified as female. Results of the present review indicate that higher levels of specific inflammatory markers are associated with lower performance on executive function measures; however, we observed significant heterogeneity in the study design and measurement of both inflammation and executive functioning, suggesting important considerations for future research.