Epidemiology of Venous Thromboembolism in Belgium: A Cohort Study.

Background: Venous thromboembolism (VTE) is a significant contributor to global morbidity and mortality. Although management strategies and the distribution of risk factors have evolved, contemporary epidemiologic data are limited and have not been previously reported for Belgium. We aimed to characterize the epidemiology of VTE in a contemporary Belgian population. Methods: We conducted secondary analyses of 1,448 participants from the Flemish Study on Environment, Genes, and Health Outcomes (FLEMENGHO), an observational, community-based, prospective cohort study. VTE cases occurring between 2000 and 2024 were identified through standardized health questionnaires, medical records, and expert adjudication. The incidence and lifetime risk of VTE were determined, and risk factors for incident VTE were assessed using Cox regression. Results: Between 2000 and 2024, 63 VTE events occurred during 34,906 person-years of follow-up, corresponding to an incidence rate of 1.80 per 1,000 person-years. At the age of 45, the estimated remaining lifetime risk of VTE was 8.2% (95% CI: 5.6-10.8). Isolated lower extremity deep vein thrombosis was the most common presentation (42.9%), followed by isolated pulmonary embolism (36.5%). Transient major risk factors were identified in 30.2% of cases. In multivariable analyses, higher BMI (adjusted hazard ratio [HR Conclusion: Despite advancements in management strategies, the burden of VTE remained substantial in this representative and well-characterized Belgian cohort. The incidence rate is consistent with findings in other Western countries.