Georgakis MK, et al. - Researchers performed a 2-sample Mendelian randomization (MR) study to investigate if genetically based circulating levels of cytokines and growth factors were related to stroke and its etiologic subtypes. In the MEGASTROKE genome-wide association study data set (67,162 cases; 454,450 controls), they assessed the associations for 41 cytokines and growth factors attained from a genome-wide association study of 8,293 healthy adults. An independent validation sample was comprised of 4,985 cases and 364,434 controls in the UK Biobank cohort. A higher risk of stroke, specifically large-artery stroke and cardioembolic stroke, was observed in relation to genetic predisposition to elevated circulating levels of monocyte chemoattractant protein-1 (MCP-1). Also, similar associations were noted for available phenotypes in the analyses in the UK Biobank. Patients with stroke vs controls had higher circulating MCP-1 levels, as seen in a meta-analysis of observational studies.