Anthropometric measures of obesity and thrombin generation: Results from the ELSA-Brasil cohort

The mechanistic link between obesity and venous thromboembolism (VTE) remains poorly understood. The thrombin generation assay (TGA) can be used as a biomarker for hypercoagulability in obesity, which is a key mechanism in VTE pathogenesis. However, data on obesity measures and TGA at population level are scarce and limited to Western countries.

To investigate the association between obesity measures and TGA parameters in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

In this cross-sectional study, we performed TGA with the calibrated automated thrombogram method using plasma samples collected at baseline from a subset of the ELSA-Brasil cohort (n = 2688). WHO cut-off values were used to categorize body mass index (BMI) and waist circumference (WC). Mean differences with 95% Confidence Intervals (CIs) in TGA parameters across BMI and WC categories were estimated by linear regression adjusted for age, sex, self-reported race, physical activity, lipids (triglycerides/low-density lipoprotein), and lipid-lowering drugs.

Endogenous thrombin potential (ETP), normalized ETP, and peak values increased dose-dependently across BMI categories at low tissue factor (TF) concentration. Mean differences between BMI ≥30 kg/m² and BMI <25 kg/m² (reference) were 149 nM.min (95% CI:110, 188) for ETP, 0.08 (95% CI:0.06, 0.10) for normalized ETP and 25 nM (95% CI:15, 34) for peak. No consistent associations of BMI with lagtime or time-to-peak were found. Similar results were obtained at high TF concentration and for WC.

ETP and peak values increased dose-dependently across BMI and WC categories, supporting a critical role of hypercoagulability in the pathogenesis of VTE in obesity.