Taller height as a risk factor for venous thromboembolism: a Mendelian randomization meta-analysis

Background Taller height is associated with greater risk of venous thromboembolism (VTE). Objectives We used instrumental variable (IV) techniques (Mendelian randomization) to further explore this relationship Methods Participants of European ancestry were included from two cohort studies [Atherosclerosis Risk in Communities (ARIC) study and Cardiovascular Health Study (CHS)] and one case-control study [Mayo Clinic VTE Study (Mayo)]. We created two weighted genetic risk scores (GRS) for height; the full GRS included 668 single nucleotide polymorphisms (SNPs) from a previously published meta-analysis and the restricted GRS included a subset of 362 SNPs not associated with weight independently of height. Standard logistic regression and IV models were used to estimate odds ratios (ORs) for VTE per 10 cm increment in height. ORs were pooled across the three studies using inverse variance weighted random effects meta-analysis Results Among 9143 ARIC and 3180 CHS participants free of VTE at baseline, there were 367 and 109 incident VTE events. There were 1143 VTE cases and 1292 controls included from Mayo. The pooled ORs from non-IV models and models using the full and restricted GRSs as IVs were 1.27 (95% CI: 1.11, 1.46), 1.34 (95% CI: 1.04, 1.73), and 1.45 (95% CI: 1.04, 2.01) per 10 cm greater height, respectively. Conclusions Taller height is associated with an increased risk of VTE in adults of European ancestry. Possible explanations for this association, including that taller people may have greater venous surface area, greater number of venous valves, or greater hydrostatic pressure, need to be explored further.