Venous thromboembolism (VTE) is the term for a blood clot that starts in a vein. You may have heard of it as deep vein thrombosis when a blood clot forms in a vein in the leg, or a pulmonary embolism when a blood clot breaks loose and travels to the lungs. VTE affects anywhere from 300,000 to 600,000 Americans each year.
Swedish scholars studying VTE and its risk factors decided to take a look at how height affected the risk of VTE. They evaluated data from over 2.7 million Swedish siblings. After controlling for as many variables as they could, they found that height played a definite factor in VTE risk. Men who were less than 5’3” tall had a 65 percent lower risk of VTE than men who were 6’2” or taller. And women who were shorter than 5’1” had a 69 percent lower risk of VTE than women who were 6’ or taller.
The researchers were not able to control for factors such as smoking, diet, and physical activity. And because this study pertained only to Swedes, its results may not be replicable among other ethnic groups or in other countries.
Still, one hypothesis is that the length of deep veins in taller people might play a role in their heightened risk of VTE, as might gravity. Taller people often have circulatory problems that don’t affect shorter people, such as colder hands and feet in wintertime. Because of the increased distance from the heart to the extremities, it is more difficult for the heart to pump blood to the extremities of taller people than shorter people. That also may allow blood to pool in the legs and clot because it takes more effort to get it back up to the heart. So if you’re tall, you might want to take special care to avoid anything that may further elevate your risk of blood clots.