Overall and abdominal obesity in relation to venous thromboembolism

Background Abdominal obesity has been shown to be a superior measure over overall obesity for detecting cardiovascular risk. Objective We conducted this study to compare the effects of overall and abdominal obesity on venous thromboembolism (VTE) and to calculate population attributable fraction for obesity for VTE. Methods Body mass index (BMI) and waist circumference (WC) were used to represent overall and abdominal obesity, respectively. In the cohort study, we included 74317 Swedish adults with anthropometric measures in 1997 and of whom 4332 were diagnosed with VTE until the end of 2017. A Mendelian randomization study was conducted to investigate causal associations of BMI, WC, and WC adjusted for BMI with VTE using data from FinnGen and UK Biobank study. Population attributable fraction was calculated for overall and abdominal obesity for VTE. Results In the cohort study, there were dose‐response associations of BMI and WC with VTE. The association between BMI and VTE was attenuated largely after adjusting for WC. Among individuals with normal BMI, participants with substantially increased WC had 53% higher (hazard ratio 1.53; 95% confidence interval, 1.28, 1.81) risk of VTE compared to those with normal WC. The causality of the association of WC adjusted for BMI with VTE was confirmed in Mendelian randomization analysis. The estimated population‐attributable risk due to elevated BMI and WC were 12.4% (8.4%, 16.5%) and 23.7% (18.1%, 29.4%), respectively. Conclusions WC might be a preferable indicator linking obesity to VTE. A large proportion of VTE cases can be prevented if the population maintained a healthy BMI and WC.