Mechanisms of Hypercoagulability Driving Stroke Risk in Obesity
Iyas Daghlas, Dipender Gill
Abstract
BACKGROUND AND OBJECTIVES: Obesity is hypothesized to induce a hypercoagulable state that increases stroke risk. The molecular mechanisms underlying this association are largely uncharacterized. We aimed to apply mendelian randomization to identify whether the association of genetically proxied body mass index (BMI) with cardioembolic stroke risk is mediated by changes in levels of circulating coagulation factors. METHODS: Genetic proxies for BMI and levels of circulating coagulation factors were obtained, respectively, from the Genetic Investigation of ANthropometric Traits consortium (n = 694,649) and deCODE cohort (n = 35,559). Genetic associations with cardioembolic stroke risk were obtained from the GIGASTROKE consortium (10,804 cases and 1,234,804 controls). We performed a two-sample mendelian randomization analysis testing the association of genetically proxied BMI with cardioembolic stroke risk, genetically proxied BMI with levels of coagulation factors, and genetically proxied levels of coagulation factors with cardioembolic stroke risk. These estimates were carried forward to mediation and sensitivity analyses. RESULTS: ). The mediated effect of genetically proxied BMI through Factor XI accounted for 26% (6%-49%) of the total effect of BMI on cardioembolic stroke. DISCUSSION: Human genetic data support increased levels of Factor XI as a mechanistic explanation for how obesity increases cardioembolic stroke risk. The clinical relevance of this association warrants further investigation within ongoing clinical trials of Factor XI inhibition.