Cardiovascular diseases (CVDs) remain a global health concern, and body mass index (BMI) is known to be associated with an increased risk of CVD, but the exact mechanisms underlying this relationship remain unclear. This study employs Mendelian randomization (MR) to investigate the causal association between BMI and electrocardiogram (ECG) indices, providing insights into potential pathways linking obesity to CVD. We conducted a comprehensive MR study utilizing large-scale genetic and ECG data from diverse populations. Instrumental variables were selected from genome-wide association studies, ensuring their relevance to BMI. Causal relationships between BMI and ECG indices, including P wave duration, PR interval, QRS duration, and QT interval, were assessed using various MR methods, with inverse variance weighted (IVW) considered as the primary analysis. Our MR analysis revealed a significant positive causal association between higher BMI and P wave duration (β = 8.078, 95% CI: 5.322 to 10.833, < 0.001), suggesting a potential mechanism through which higher BMI may contribute to arrhythmogenic risks. However, no significant causal associations were observed between BMI and PR interval, QRS duration, or QT interval (all > 0.005). In addition, our study also found that there is no horizontal pleiotropy between BMI and P wave duration, PR interval, QRS duration, and QT interval, suggesting that the conclusions of this study are robust. This study supports a causal relationship between elevated BMI and prolonged P wave duration, a marker of increased atrial arrhythmogenic risk. Further investigations are still needed to elucidate the underlying mechanisms.

中文翻译：

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体重指数与心电图指数之间的关联：孟德尔随机化研究

心血管疾病 (CVD) 仍然是全球健康问题，已知体重指数 (BMI) 与 CVD 风险增加相关，但这种关系背后的确切机制仍不清楚。本研究采用孟德尔随机化 (MR) 来调查 BMI 和心电图 (ECG) 指数之间的因果关系，从而深入了解肥胖与 CVD 之间的潜在联系。我们利用来自不同人群的大规模遗传和心电图数据进行了全面的 MR 研究。工具变量选自全基因组关联研究，确保它们与体重指数的相关性。使用各种 MR 方法评估 BMI 和 ECG 指数（包括 P 波持续时间、PR 间期、QRS 持续时间和 QT 间期）之间的因果关系，并以逆方差加权 (IVW) 作为主要分析。我们的 MR 分析显示较高的 BMI 与 P 波持续时间之间存在显着的正因果关系（β = 8.078，95% CI：5.322 至 10.833，< 0.001），表明较高的 BMI 可能导致心律失常风险的潜在机制。然而，BMI 与 PR 间期、QRS 持续时间或 QT 间期之间没有观察到显着的因果关系（均 > 0.005）。此外，我们的研究还发现BMI与P波持续时间、PR间期、QRS时限和QT间期之间不存在水平多效性，表明本研究的结论是稳健的。这项研究支持体重指数升高和 P 波持续时间延长之间存在因果关系，P 波持续时间延长是房性心律失常风险增加的标志。仍需要进一步研究以阐明潜在机制。