PHILADELPHIA — Generally speaking, there aren’t many drawbacks to being tall. People of higher stature never have to worry about peeking their head through the crowd at a concert, and they can always reach that elusive cereal box on the top shelf. Unfortunately, a new study has concluded that being tall may come with at least one medical disadvantage. Taller people are at a greater risk of developing arterial fibrillation (AFib), an irregular or rapid heartbeat.
AFib can lead to more serious problems like stroke and heart failure if left untreated. It’s a relatively common heart condition that impacts more than 33 million people all over the world.
According to researchers at the University of Pennsylvania Medical School, one’s risk of developing atrial fibrillation actually increases in accordance with their height. In comparison to people of average height (five feet, seven inches), an individual’s risk of AFib increases by 3%, regardless of other clinical risk factors, with each additional one-inch height increase.
This research, which clearly illustrates a strong connection between genes associated with height and AFib onset probability, is especially noteworthy because it is one of the first ever to show that height may be a causal, not correlational, risk factor for the condition.
“Our findings suggest it may be beneficial to incorporate height into risk-prediction tools for AFib,” says lead study author Michael Levin, MD, in a media release. “While current guidelines advise against widespread screening for AFib, our findings show that a certain group of patients — specifically, very tall patients — may benefit from screening.”
Furthermore, there are a number of clinical risk factors that can elevate one’s chances of developing the condition, such as high blood pressure, diabetes, and obesity. Previous observational studies had found that taller people appeared to be at an elevated risk of developing AFib, but whether this relationship is causal or correlational has remained largely a mystery.
So, in order to further investigate this matter, researchers utilized data collected by the Genetic Investigation of Anthropometric Trials (GIANT) consortium, a huge research initiative aimed at identifying genetic variants linked to height that included over 700,000 people. Additionally, data collected by the Atrial Fibrillation Genetics (AFGen) consortium was included as well. This project included over 500,000 participants and focused on identifying genetic variants associated with AFib.
With this enormous dataset, the research team performed a specialized statistical method that uses genetics to precisely estimate the relationship between two traits. They discovered that the very same genetic variants linked to height were also strongly associated with AFib. Simply put, this suggests to the researchers that elevated height may cause AFib. This finding remained consistent even after researchers adjusted for other risk factors such as diabetes or blood pressure.
Finally, a second analysis was performed on 7,000 individuals currently enrolled in the Penn Medicine Biobank, a collection of blood and tissue samples collected by UPenn in an effort to support health research efforts. It was again noted that the genetic variants associated with height were strongly linked to an increased chance of developing atrial fibrillation.
“These analyses show how we can use human genetics to help us better understand causal risk factors for common disease,” says senior study author Scott Damrauer, MD. “They also illustrate how we can combine summary-level statistics from large published studies with individual level data from institutional biobanks to further our understanding of human disease.”
The study is set to be presented at the American Heart Association’s 2019 Scientific Sessions.