The causes of venous insufficiency and varicose veins largely depend on genetics, but age, significant time spent standing and your activity levels can affect your vein health as well. Women are about two times more likely to suffer from varicose veins than men. In a healthy vein, valves keep the blood flowing upwards and back to your heart from the legs and arms. However, sometimes these valves become damaged, allowing small backflows of blood to become trapped in the veins. The result is a swollen and often painful, bulging vein that is typically seen in the legs.
Rarely, varicose veins can develop after trauma.