Each year, more than 100,000 Americans die from blood clots that disrupt circulation or breathing, known as venous thromboembolisms (VTE). The clots often form deep in the veins or lungs, and are most common in people with high body mass index. Recently, new studies have suggested that people of taller height and European ancestry could be at risk for the condition, too. The School of Public Health recently completed the first study examining the link between height and VTE from a genetic perspective, and confirmed that taller height is indeed related to increased risk of VTEs.
The study was published in the the Journal of Thrombosis and Haemostasis.
“It’s interesting because many studies have shown how shorter people are at greater risk for coronary heart disease and most other arterial thrombotic diseases,” says lead author and PhD student Nick Roetker. “In the case of venous thromboembolisms, it’s sort of the opposite.”
The paper used genetic and health data from participants in three related studies, including the school’s Atherosclerosis Risk in Communities (ARIC) study. The study was co-written by Professors Aaron Folsom and Jim Pankow, as well as Associate Professors Pamela Lutsey, Weihong Tang, and Richard Maclehose.
“We found that for every 10 centimeters in height, there’s a 30-40 percent relative increase risk of VTE,” says Roetker. “So, we would expect a person who is 182 cm to have 1.3-1.4 times greater risk of VTE compared to someone who is 172 cm, assuming they share the same values for other risk factors.”
The association between height and VTE occurrence was confirmed using a relatively new study technique known as Mendelian Randomization. For the method, the researchers looked to see if genetic characteristics associated with taller height were also associated with greater risk of VTE. In theory, since genetic characteristics are randomly inherited, the technique allows for better estimation of the true association between height and VTE risk compared to traditional observational studies, where the appearance of a relationship might be created by confounding factors.
Roetker says the findings reinforce that height is somehow related to VTEs, but the news is more significant for researchers than health care providers.
“We still don’t know why taller people have greater risk for VTE and the study doesn’t provide a way for predicting them,” says Roetker. “What the the study does show is that Mendelian Randomization could be useful for researching VTEs and that continuing to investigate the link with height could help us to better understand the pathophysiology of the disease.”
Roetker says that he and his advisers are excited about their success using Mendelian Randomization and are gearing up to employ the method in additional disease-related studies.