Key points Do women have a lower risk of atrial fibrillation (AF) after accounting for other AF risk factors, and do AF risk factors differ between men and women? Findings In this cohort study of 25,119 participants within the Vitamin D and Omega-3 Trial (VITAL) Rhythm Study, women had a higher risk of developing AF than men when height and weight were controlled, rather than of body mass index, in the multivariate analysis. AF risk factors were similar for women and men. Meaning The results suggest that, for a given height and weight, women have a higher risk of incident AF than men, and primary prevention with risk factor modification should be equally effective; These findings emphasize the need to prevent AF in women. |
Importance
Women have a lower incidence of atrial fibrillation (AF) compared to men in several studies, but it is unclear whether this sex difference is independent of sex differences in prevalent cardiovascular disease (CVD), body size and other risk factors.
Aim
To examine sex differences in the incidence of AF and whether risk factors for AF differ by sex in a contemporary cohort of men and women without prevalent CVD.
Design, environment and participants
This was a prospective cohort analysis within the Vitamin D and Omega-3 Trial (VITAL) Rhythm Study, a randomized trial that examined the effect of vitamin D and ω-3 fatty acid supplementation on incident AF among men. 50 years or older and women 55 years or older with no history of prevalent AF, CVD, or cancer at baseline. Data was analyzed from September 29, 2020 to June 29, 2021.
Exhibitions
Sex, height, weight, body mass index (BMI), body surface area (BSA), and other risk factors for AF at study enrollment.
Main results and measures
AF incident confirmed by review of medical records.
Results
A total of 25,119 individuals (mean [SD] age, 67.0 [7.1] years; 12,757 women [51%]) were included in this study. During a median (IQR) follow-up of 5.3 (5.1-5.7) years, 900 confirmed AF incidents occurred among 12,362 men (495 events, 4.0%) and 12,757 women (405 events , 3.2%).
After adjustment for age and treatment assignment, women had a lower risk of incident AF than men (hazard ratio [HR], 0.68; 95% CI, 0.59-0.77; P < 0.001). The inverse association between female sex and AF persisted after adjustment for race and ethnicity, smoking, alcohol consumption, hypertension, diabetes (type 1, type 2, gestational), thyroid disease, exercise, and BMI (HR, 0.73 ; 95% CI, 0.63-0.85; P <.001).
However, female sex was positively associated with AF when height (HR, 1.39; 95% CI, 1.14-1.72; p = 0.001), height, and weight (HR, 1.49; 95% CI, 1.21-1.82; P < 0.001), or BSA (HR, 1.25; 95% CI, 1.06-1.49; P = 0.009) were replaced by BMI at multivariate model. In stratified models, associations of risk factors with incident AF were similar for women and men.
Conclusions and relevance
In this cohort study, findings suggest that after controlling for height and/or body size, women without CVD at baseline had a higher risk of AF than men, suggesting that sex differences in body size explain a large part of the protective association between female sex and AF. These data underscore the importance of AF prevention in women.
Comments
A new study from the Smidt Heart Institute shows that women , when height is taken into account , are 50% more likely to develop atrial fibrillation than men
Science has long shown that men are at higher risk of developing atrial fibrillation (AFib) than women; but it has never been fully understood why women would be protected from developing the condition. New research from the Smidt Heart Institute at Cedars-Sinai challenges this conventional wisdom by showing that women, when height is taken into account, have a 50% higher risk of developing an abnormal heart rhythm disturbance compared to men.
The new findings, published today in the peer-reviewed journal JAMA Cardiology , suggest that doctors should remain vigilant in promoting atrial fibrillation prevention and early interventions among patients, both men and women.
“This is the first study to show a real change in the risk of atrial fibrillation,” said Christine Albert, MD, MPH, chair of the Department of Cardiology at the Smidt Heart Institute and lead author of the study. Albert also led the national VITAL Rhythm trial on which these findings are based. “In this population of 25,000 people without prior heart disease, after adjusting for height differences , women had a higher risk of developing AF than their male counterparts, more than 50%.”
As Albert explains, the taller an individual is, the greater the risk of AFib . This is why it has been shown that women have a lower risk of suffering from the disease, since they tend to be shorter than men.
"However, our study surprisingly suggests that if a man and a woman are the same height, the woman would be more likely to develop AFib," Albert said. “Now the question has changed: instead of why women are protected, we must now try to understand why women are at greater risk.”
Atrial fibrillation is the most common type of abnormal heart rhythm and, without treatment, can lead to stroke or heart failure. Once a woman is diagnosed with AFib, she is more likely to experience one of these adverse consequences than a man, making AFib prevention extremely important in women.
Patients diagnosed with the condition can be treated with blood thinners and outpatient procedures, such as cardioversion or ablation, or cardiac surgery, but women are less likely to undergo invasive treatments for atrial fibrillation, such as ablation.
It is estimated that by 2030, more than 12.1 million Americans will have the condition. Albert notes that as the size of the general population increases, both in height and weight, cardiologists can expect more people to be diagnosed with atrial fibrillation.
“With incidence rising, it is more imperative than ever to offer preventive strategies and early diagnostic interventions to all patients,” said Albert, Professor of Cardiology at Cedars-Sinai and Lee and Harold Kapelovitz Distinguished Chair in Cardiology .
The most effective prevention strategies against atrial fibrillation in men and women, Albert says, include maintaining a healthy weight, controlling blood pressure, limiting alcohol consumption, and getting moderate exercise.
"These lifestyle modifications are important for people at risk for atrial fibrillation, but also important modifications that all women can consider to prevent other heart-related conditions," said Noel Bairey Merz, MD, director of the Heart Center. for women Barbra Streisand in Smidt Heart. Institute and pioneer in women’s heart disease.
Bairey Merz, who was not involved in the study, says the data underscore the importance of preventing atrial fibrillation in women.
“Atrial fibrillation is a disease we want to prevent, regardless of sex or gender,” Albert said. "This informative study is an important step for the medical community to take note and begin discussing the risk of atrial fibrillation with all patients, whether male or female."
Funding: The VITAL Rhythm trial was supported by R01HL116690, and the VITAL trial was supported by grants U01CA138962 and RO1CA138962, which included support from the National Cancer Institute, National Heart, Lung, and Blood Institute, Office of Dietary Supplements , the National Institute of Neurological Disorders and Stroke, and the National Center for Complementary and Integrative Health of the National Institutes of Health.
