Obesity and shorter QT intervals: sex- and adiposity distribution-specific patterns of ventricular repolarization in healthy Asian youth.

OBJECTIVE

Obesity is linked to prolonged ventricular repolarization (QT interval) in older populations, but its electrophysiological impact in healthy Asian youth remains unclear. This study aimed to assess the association between adiposity and ventricular repolarization in this population.

METHODS

This cross-sectional study included 3,156 healthy Asian youth (mean age 19.6 years). Adiposity was quantified using body mass index (BMI), body fat percentage (BFP), waist circumference (WC), and waist-to-hip ratio (WHR). The primary outcome was the Fridericia-corrected QT interval (QTcF). Sex-stratified robust regression was employed, and mediation by heart rate variability (HRV) was explored.

RESULTS

Greater adiposity was associated with shorter QTcF, contrary to the conventional paradigm. This association exhibited marked sexual dimorphism. In males, all four adiposity indices were significantly linked to QTcF shortening (e.g., β = -2.97 ms per SD increase in BMI). In females, significant associations were confined to BMI and BFP. Furthermore, in females, vagal tone (rMSSD) and sympathovagal balance (LF/HF) statistically mediated part of the BMI/BFP-QTcF relationship, accounting for 6.3% to 9.8% of the effect. Sensitivity analyses confirmed robustness.

CONCLUSION

In healthy Asian youth, obesity is associated with shorter ventricular repolarization, modulated by sex and adiposity type. These findings suggest unique early-life electrophysiological adaptations and underscore the importance of considering sex and body composition in cardiovascular risk assessment for young populations.