Association between body mass index and electrocardiogram indices: A Mendelian randomization study

Area of Science:

• Cardiovascular genetics
• Obesity research
• Epidemiology

Background:

• Cardiovascular diseases (CVDs) are a major global health issue.
• Obesity, measured by body mass index (BMI), is linked to increased CVD risk, but causal pathways are unclear.
• Electrocardiogram (ECG) indices may reveal mechanisms linking BMI to CVD.

Purpose of the Study:

• To investigate the causal association between BMI and ECG indices using Mendelian randomization (MR).
• To explore potential mechanisms linking obesity to cardiovascular disease risk.

Main Methods:

• A comprehensive MR study using large-scale genetic and ECG data.
• Instrumental variables for BMI were selected from genome-wide association studies.
• Causal relationships between BMI and P wave duration, PR interval, QRS duration, and QT interval were assessed using MR methods, primarily inverse variance weighted (IVW).

Main Results:

• A significant positive causal association was found between higher BMI and prolonged P wave duration (β = 8.078, p < 0.001).
• No significant causal associations were observed between BMI and PR interval, QRS duration, or QT interval (all p > 0.005).
• The study found no evidence of horizontal pleiotropy, supporting the robustness of the findings.

Conclusions:

• Elevated BMI is causally associated with prolonged P wave duration.
• Prolonged P wave duration is a marker of increased atrial arrhythmogenic risk.
• Further research is needed to fully elucidate the underlying mechanisms linking BMI to atrial arrhythmogenesis.