Tall people draw the short straw when it comes to developing blood clots in their veins, according to a study of more than two million Swedish siblings.

For men 6-foot-2 or taller, researchers found a risk increase of 65 percent when compared to men 5-foot-3 or shorter. Women at least 6 feet tall showed a 69 percent increased risk of venous thromboembolism versus women shorter than 5-foot-1.

These findings were published in Circulation: Cardiovascular Genetics.

“It could just be that because taller individuals have longer leg veins there is more surface area where problems can occur,” lead researcher Bengt Zöller, MD, PhD, associate professor at Lund University and Malmö University Hospital in Malmö, Sweden, said in a statement. “There is also more gravitational pressure in leg veins of taller persons that can increase the risk of blood flow slowing or temporarily stopping.”

Venous thromboembolism affects up to 600,000 Americans each year, making it the third leading cause of heart attack and stroke, according to the CDC. Zöller noted the incidence of thrombosis has increased over time, which could be tied to height gains in populations around the world.

“I think we should start to include height in risk assessment just as overweight, although formal studies are needed to determine exactly how height interacts with inherited blood disorders and other conditions,” he said.