Deep Vein Thrombosis (DVT) is a serious medical condition marked by the formation of blood clots in deep veins, most commonly in the legs.

Understanding the risk factors is essential for prevention, timely diagnosis, and effective management of this potentially life-threatening disorder.

Deep Vein Thrombosis

DVT arises when blood clots obstruct venous blood flow in deep veins, potentially leading to complications like pulmonary embolism if clots dislodge and reach the lungs. Numerous factors contribute to an increased risk of developing DVT, ranging from inherited genetic predispositions to acquired medical and lifestyle elements.

These risk factors interact in complex ways, influencing clot formation through effects on blood flow, vessel integrity, and blood coagulability.

Major Risk Factors for Deep Vein Thrombosis

1. Age and Immobility

Age is a significant risk factor, with individuals over 60 years facing a heightened susceptibility due to natural changes in blood coagulation and venous valve function. Prolonged immobility—such as extended bed rest, long-duration travel, or paralysis—reduces calf muscle contractions that normally promote venous return, leading to blood stasis conducive to clot formation.

2. Surgery and Trauma

Surgical procedures, particularly those involving the pelvis, abdomen, hips, or legs, raise DVT risk both from vascular injury and immobility during recovery. Trauma or injuries that damage veins similarly create an environment favorable to thrombosis.

3. Genetic and Acquired Coagulation Disorders

Inherited conditions such as Factor V Leiden mutation, prothrombin gene mutation (G20210A), and deficiencies in natural anticoagulants like protein C, protein S, and antithrombin markedly increase the tendency for clotting. These genetic risks may triple or even ten-fold elevate DVT probability.

4. Hormonal Influences

Elevated estrogen levels, whether from contraceptives, hormone replacement therapy, or pregnancy, intensify clotting potential by altering coagulation pathways and increasing venous pressure, particularly in pelvic veins during pregnancy and postpartum periods.

5. Chronic Medical Conditions

Certain illnesses elevate thrombosis risk, including:

- Cancer and its treatments, which may produce procoagulant substances and compress veins.

- Heart and lung diseases reducing effective circulation.

- Inflammatory bowel diseases like Crohn's and ulcerative colitis.

- Kidney disorders and obstructive sleep apnea also contribute indirectly through systemic inflammation and altered blood properties.

Dr. Richard H. Ofstein, a vascular medicine specialist, explains, "Deep vein thrombosis results from a triad of factors: impaired blood flow, vessel wall injury, and hypercoagulability. Recognizing patient-specific risk profiles enables targeted prevention that can significantly reduce morbidity and mortality."

Similarly, Dr. Jean M. Connors, a hematologist, states, "Inherited thrombophilias, such as Factor V Leiden or the prothrombin gene mutation, increase the risk of clotting, but it’s often the presence of acquired factors—like surgery, immobility, or hormonal therapy—that triggers an actual thrombotic event. Understanding how these factors interact is key to effective risk stratification and prevention."

Deep Vein Thrombosis risk emerges from a spectrum of factors that impair venous blood flow, injure vein walls, or increase blood coagulability. Awareness and early identification of these risks—especially the interplay between inherited and acquired factors are essential for preventing DVT and its complications.