Sex differences in atrial fibrillation incidence among individuals with metabolic syndrome: a narrative mini review

Background Sex differences influence the development and clinical expression of many chronic cardiometabolic diseases. Atrial fibrillation (AF), the most common sustained arrhythmia, frequently coexists with metabolic syndrome (MetS), yet whether MetS confers different AF risk in men and women remains incompletely understood. Content Epidemiological evidence consistently demonstrates that MetS increases the risk of incident AF by approximately 1.4- to 1.9-fold. Among MetS components, elevated blood pressure and abdominal obesity show the strongest associations with AF onset. Most studies also reveal that men have higher rates of AF than women across all age groups, although AF incidence in women rises sharply after menopause. In individuals with MetS, similar sex-related trends are observed: men typically exhibit a higher and earlier AF incidence, whereas women experience a delayed but steep increase in older age. Biological differences—particularly sex hormone–driven variations in fat distribution, lipid metabolism, insulin sensitivity, and inflammation—may underlie these patterns. Premenopausal women tend to accumulate subcutaneous, metabolically benign fat, whereas men preferentially store visceral fat, promoting earlier metabolic dysfunction and AF susceptibility. After menopause, declining estrogen levels shift women toward central adiposity and cardiometabolic deterioration, narrowing the AF incidence gap. Sex-related differences in autonomic balance and adiposity-related sympathetic activation may further modulate AF risk. Conclusion While MetS increases AF risk in both sexes, accumulating evidence suggests that the magnitude, timing, and underlying mechanisms of this risk differ between men and women. Better integration of sex-specific biological pathways into AF prevention strategies is warranted.