Related Experiment Video
Updated: Feb 7, 2026

Author Spotlight: Advancing Cancer Associated Thrombosis Research in Rodent Models
Published on: January 5, 2024
Factor V levels and risk of venous thrombosis: The MEGA case-control study
Inge M Rietveld1,2, Mettine H A Bos1,2, Willem M Lijfering1,2,3
1Einthoven Laboratory for Experimental Vascular Medicine Leiden University Medical Center Leiden The Netherlands.
Background:
Blood coagulation levels are associated with risk of venous thrombosis (VT). The role of factor (F)V is ambiguous since it plays a dual role in coagulation: it has a procoagulant role when it serves as a cofactor for the activation of thrombin and it has an anticoagulant role by enhancing the inactivation of activated FVIII.
Objectives:
To elucidate the association of FV levels with risk of VT.
Patients/Methods:
We analyzed FV antigen levels in 2377 patients with VT and 2943 controls from the MEGA study. FV levels were categorized according using the 1st, 2.5th, 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles of FV levels in controls as cut-off points. Odds ratios (ORs) were estimated using logistic regression models and adjusted for age and sex, liver disease, FVIII levels, FV Leiden, and TFPI.
Results:
The risk estimates were U-shaped with increased ORs for the lowest (<0.57 U/dL) levels (OR 1.46; 95% CI 0.87-2.43) as well as the highest (>1.22 U/dL) (OR 1.86; 95% CI 1.46-2.37) levels as compared with the reference group (25th-50th percentile). FVIII adjustment led to attenuation of the OR for high FV levels (OR 1.14; 95% CI 0.88-1.48), with little change for low FV levels (OR 1.68; 95% CI 0.97-2.91). Other adjustments had limited effects.
Conclusions:
We found high FV levels to be associated with increased risk for VT, which was explained by concurrently raised FVIII levels. For low levels of factor V, the increased risk for VT could not be explained by the mechanisms we explored.
Related Concept Videos
Venous Thrombosis I: Introduction
Venous Thrombosis II: Clinical Manifestations and Diagnostic Studies
Venous Thrombosis III: Interprofessional Care
Venous Thrombosis IV: Nursing Management
Factors Affecting the Risk of Infection
The integrity and count of the white blood cells help the body resist pathogens and fight infection. When impaired, it reduces the body's resistance to pathogens. The acidic pH levels of the gastrointestinal, genitourinary tracts, and skin...
Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast,...

