Tall people more likely to develop atrial fibrillation

By Angela Betsaida B. Laguipo, BSNNov 13 2019

Size may matter when it comes to having a safe and steady heart. A new study shows tall people are more likely to develop from an irregular heartbeat, known as atrial fibrillation (AFib).

Atrial fibrillation, Afib or AF, is the most common sustained arrhythmia. It is an irregular heart rhythm that causes the heart to pump blood less efficiently. Though not life-threatening, if it’s left untreated, it can heighten the risk of heart attack and stroke.

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Increased body size has been linked to AFib, but the connection has not been well understood. Now, a team of researchers at the School of Medicine at the University of Pennsylvania found that taller people are more likely to develop atrial fibrillation, showing a strong link between genetic risk factors associated with height and one’s risk for AFib.

The study, which will be presented at the American Heart Association’s 2019 Scientific Sessions in Philadephia, demonstrates that the risk for AFib soared as one’s height increased. Every one-inch increase in height translates to approximately a three-per cent increase in the risk of having AFib, which is independent of other clinical factors.

In the study, the average height is 5 feet 7 inches, which means that those who are taller than the average may have increased risk of having AFib.

"Our findings suggest it may be beneficial to incorporate height into risk-prediction tools for AFib," Dr Michael Levin, study lead author and a Cardiovascular Medicine fellow at Penn, said.

"While current guidelines advise against widespread screening for AFib, our findings show that a certain group of patients--specifically, very tall patients--may benet from screening,” he added.

Height boosts the risk of developing AFib

To arrive at their findings, the team studied the link between height and Afib from data gathered by the Genetic Investigation of Anthropometric Trials (GIANT) consortium. The GIANT study examined more than 700,000 individuals to determine genetic variants tied to height. Aside from getting data from GIANT, the team also collated information from the Atrial Fibrillation Genetics (AFGen) consortium, which included more than half a million people to determine genetic variants for AFib.

In other studies, taller people have been found to have a higher risk of developing AFib. But, the team wanted to determine if height can cause AFib.

After collating data from the two consortiums, the investigators found that genetic variants tied to height were also markedly linked to AFib, showing that increased height may be a cause of atrial fibrillation. In fact, the researchers found that the connection remained strong even after adjusting conventional Afib risk factors, including heart disease, obesity, diabetes, and elevated blood pressure.

To further strengthen their findings, the researchers enrolled 7,000 individuals in the Penn Medicine Biobank and used a statistical method to perform an individual-level analysis. They found that height and the other genetic variants linked to height are strongly associated with a heightened risk of developing AFib, even without traditional risk factors.

The researchers noted that the analysis of data has shown how human genetics can help in determining causal risk factors for common conditions, which can provide better therapeutics and preventive measures in the future.

Atrial fibrillation in detail

Atrial fibrillation is the most common type of heart arrhythmia, with about 2.7 to 6.1 million people affected in the United States alone. Across the globe, about 33.5 million people had AFib in 2010.

AFib is an irregular heartbeat or arrhythmia that can lead to many heart-related complications such as heart failure, stroke, and the formation of blood clots.

The condition increases with age, and the most common risk factor is high blood pressure. The other risk factors of AFib include obesity, diabetes, ischemic heart disease, heart failure, chronic kidney disease, hyperthyroidism, enlargement of the left chambers of the heart, and heavy alcohol use.

Though in most cases, many patients with AFib don’t know they have it since they don’t develop any symptoms. But, when the disease progresses, the common signs and symptoms include lightheadedness, irregular heartbeat, heart palpitations (rapid, pounding, or fluttering), extreme fatigue, chest pain, and difficulty of breathing.