Atrial fibrillation disrupts the heartbeat and is one of the most common cardiac arrhythmias. It affects women and men differently often – but differently than previously assumed. The risk of this disease appears to be related to body size.

Women are at greater risk than men of developing atrial fibrillation – taking into account the difference in body size. So far, many studies had shown that the risk of such a cardiac arrhythmia is greater in men than in women. According to the new study, however, this result is due to the fact that men are taller than women on average and the risk of this disease increases with height. With regard to other risk factors such as age, ethnic origin or high blood pressure, there were no significant differences between the sexes in the current study. The study by the group led by Christine Albert from the Cedars-Sinai Medical Center in Los Angeles (California, USA) has been published in the journal “JAMA Cardiology”.

It has been a mystery to medical professionals why men appear to be at greater risk of developing atrial fibrillation. “However, our study surprisingly indicates that if a man and a woman are the same height, the woman has a higher risk of developing atrial fibrillation,” Albert is quoted as saying in a statement from her institute.

This has fundamentally changed the approach to finding the cause of gender differences: “Instead of asking why women are protected, we now have to try to understand why women are at greater risk.” The analysis of the research team showed: In men and women of the same height, women have an up to 39 percent higher risk of developing atrial fibrillation. If you also take body weight into account, the risk is even 49 percent higher.

More than 25,000 women and men without cardiovascular disease were included in the study between November 2011 and March 2014. The men were 50 years or older, the women 55 years or older. 51 percent of the study participants were women, 20 percent black. They were followed up between 5.1 and 5.7 years.

For most physical characteristics and risk factors, there were only very small differences between the sexes. However, when the researchers kept body weight or height constant in the analysis, women were found to have a greater risk of atrial fibrillation. “Atrial fibrillation is a disease that we want to prevent, regardless of gender,” emphasizes Albert. The medical community should take the results as an opportunity to talk to all patients, whether male or female, about the risk of atrial fibrillation.

(This article was first published on Wednesday, August 31, 2022.)