Genetic Variants Significantly Increase Risk of Leg Blood Clots by 180%

Recent research has uncovered new genetic factors that considerably elevate the risk of developing blood clots in the legs. Blood clots can occur in arteries or veins, with differing causes and health implications. In Sweden, genetic predisposition plays a significant role, with nearly half of venous thrombosis cases linked to hereditary factors.

A team from Lund University in Sweden identified three gene variants—related to ABO, F8, and VWF—that, when combined, increase the likelihood of venous blood clots by up to 180%. This discovery marks the strongest genetic risk factor since the identification of Factor V Leiden, which affects about 10% of Swedes.

Blood clots in arteries typically result from plaque rupture and can lead to strokes or heart attacks. Conversely, venous clots tend to form when blood flow in the legs slows or stagnates, activating coagulation and possibly resulting in pulmonary embolism if the clot travels to the lungs.

The risk factors for venous thrombosis include age, obesity, tall stature, and inactivity, especially in the context of sedentary lifestyles. Damaged vein valves, often in taller individuals, can impair blood flow, further increasing risk. Unlike arterial disease, high blood pressure and cholesterol are less relevant for venous clots.

Obesity remains a significant risk factor, negatively impacting venous circulation and increasing clotting factor levels. Lifestyle factors such as diet also influence risk, with high processed food intake slightly elevating it, whereas diets rich in omega-3 fatty acids may offer some protection.

Certain situations heighten the risk of blood clots, such as long flights, bed rest, surgery, or pregnancy—conditions where blood flow is reduced or vessel walls are damaged. In these cases, prophylactic blood-thinning medications might be recommended.

The newly identified gene variants—present in a broad range of populations worldwide—offer promising avenues for personalized treatment and risk assessment. Understanding the number of genetic risk factors could guide decisions on anticoagulant therapy duration, emphasizing the importance of individualized medical approaches.

This discovery underscores the evolving understanding of genetic influences on venous thrombosis and highlights the potential for improved prevention and management strategies based on genetic profiling.