Does Obesity Raise AF Risk Directly or Via Comorbidities?

TOPLINE: 

Individuals with overweight or obesity have a higher risk for atrial fibrillation (AF) than those with normal weight. Nearly one fourth of the increased risk with obesity is mediated by comorbid conditions, whereas the remaining risk is directly mediated by obesity.

METHODOLOGY:

• Obesity is associated with an increased risk for AF, yet it remains unclear whether this risk stems directly from excess adiposity or is mediated by comorbid conditions.
• Researchers conducted a retrospective cohort study of patients aged ≥ 40 years with a documented BMI across German general practices between 2005 and 2023.
• Participants were categorized as underweight (BMI < 18.5), normal weight (18.5-24.9), overweight (25.0-29.9), or obesity (≥ 30).
• The primary outcome was incident AF within 10 years of the index date.
• A causal mediation analysis estimated the proportion of AF risk mediated by comorbidities, including type 2 diabetes, hypertension, dyslipidemia, ischemic heart disease, and heart failure.

TAKEAWAY:

• The study included 1 22,464 participants with normal weight (mean age, 58.9 years; 61.6% women), 150,783 with overweight (mean age, 60.7 years; 44.5% women), and 112,674 with obesity (mean age, 60.1 years; 53% women).
• Over 10 years, AF occurred in 7.2% of participants with normal weight, 10.1% with overweight, and 13.2% with obesity.
• Compared to those with normal weight, the risk for AF was 43% higher among individuals with obesity (P <.001) and 12% higher among those with overweight (P < .001), with greater risks in men.
• Mediation analysis revealed that 27% of obesity-related AF risk was mediated by comorbidities, whereas 79% was attributed to direct effects of obesity.

IN PRACTICE:

“Effective management of hypertension, diabetes and dyslipidaemia could help to achieve a meaningful reduction in the proportion of AF cases attributable to obesity. At the same time, the persistent direct effect of BMI on AF, despite adjustment for comorbidities, indicates that weight reduction must remain a central focus of preventive strategies,” the authors wrote.

SOURCE:

This study was led by Jamschid Sedighi, MD, Justus-Liebig-University in Giessen, Germany. It was published online in Diabetes, Obesity and Metabolism.

LIMITATIONS:

BMI was measured only at baseline; thus, associations reflect initial BMI rather than changes over time. Confounding factors may have remained. Reliance on diagnostic codes may have underestimated the cases of paroxysmal or asymptomatic AF. 

DISCLOSURES:

No specific study funding was reported. Two authors disclosed receiving speaker/consulting honoraria from AstraZeneca and Pfizer, and one also received honoraria from additional sources including Novartis, Berlin-Chemie, and Lilly.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.