[Is obesity still a coronary risk factor?]

Area of Science:

• Cardiology
• Metabolic Health
• Epidemiology

Background:

• Obesity, particularly abdominal obesity, is a known risk factor for coronary artery disease (CAD).
• The relationship between obesity and outcomes (mortality, myocardial infarction) in established CAD patients remains debated, with prior studies yielding contradictory results.
• The 'obesity paradox' or 'reverse epidemiology' describes findings where higher body fat predicts better survival in certain cardiovascular conditions.

Discussion:

• A recent meta-analysis of over 250,000 CAD patients indicated overweight individuals had better survival and fewer cardiovascular events compared to normal weight individuals.
• Obesity was associated with increased total mortality only in patients with a history of coronary artery bypass graft surgery.
• Severe obesity correlated with significantly higher cardiovascular mortality, but not increased total mortality.

Key Insights:

• Overweight status may be associated with improved survival in established coronary artery disease.
• Severe obesity presents a higher cardiovascular mortality risk in CAD patients, challenging the simple 'obesity paradox' narrative.
• Current metrics may inadequately assess body composition and its impact on CAD outcomes.

Outlook:

• Further research is needed to identify optimal methods for assessing body fat and its clinical significance in CAD.
• Investigating the role of muscle-to-fat ratio and physical fitness is crucial for a comprehensive understanding of obesity's impact on cardiovascular health.
• Future studies should explore the unique contributions of body composition beyond simple BMI in predicting clinical outcomes for CAD patients.