AHA Coronary Artery Disease Risk Factors
The American Heart Association (AHA) identifies hypertension, hypercholesterolemia, cigarette smoking, diabetes mellitus, family history of premature CAD, age, and obesity as the major risk factors for coronary artery disease (CAD). 1
Traditional Modifiable Risk Factors
Hypertension
- Significant risk factor for CAD across all age groups
- Risk increases continuously with higher blood pressure levels
- Even non-hypertensive ranges show correlation with CAD risk
- Both systolic and diastolic pressures contribute to risk, with systolic becoming more important after age 60 2
Hypercholesterolemia/Dyslipidemia
- Elevated total cholesterol and LDL cholesterol
- Reduced HDL cholesterol
- AHA defines high total cholesterol as ≥200 mg/dL (5.15 mmol/L) 1
- AHA defines high LDL cholesterol as ≥130 mg/dL (3.35 mmol/L) 1
Cigarette Smoking
- Strong independent risk factor
- Both active smoking and secondhand smoke exposure increase risk 1
- Risk begins to decrease soon after cessation but may take years to approach non-smoker levels
- Paradoxically, smokers with ACS tend to have better short-term outcomes due to younger age at presentation and less severe underlying CAD ("smoker's paradox") 1
Diabetes Mellitus
- Major risk factor that significantly increases mortality and heart failure risk in ACS patients
- Carries prognostic significance beyond the extent of underlying CAD 1
- Increases risk of multivessel disease
Non-Modifiable Risk Factors
Age
- Risk increases with advancing age, with steepest increase after age 70 1
- Independent risk factor beyond the greater extent of CAD in older adults
Family History of Premature CAD
- Defined as documented MI, angiographic CAD, angina, or sudden cardiac death in a first- or second-degree relative ≤55 years old 1
- Sibling history carries stronger predictive value than parental history 1
- Associated with increased coronary calcium scores and 30-day cardiac events 1
Male Sex
- Men have higher risk of CAD at younger ages
- Women present with CAD later in life on average
- When STEMI occurs, women have worse outcomes despite adjustment for age and comorbidities 1
Additional Risk Factors
Obesity/Overweight
- Associated with higher long-term cardiovascular risk 1
- Severe obesity particularly increases risk 1
- Paradoxically, overweight/obese patients may have better short-term outcomes with ACS ("obesity paradox") due to younger presentation age and more aggressive management 1
Physical Inactivity/Low Fitness
- Independent risk factor for CAD 1
- Contributes to other risk factors including obesity, hypertension, and diabetes
Extracardiac Vascular Disease
- Presence of carotid, aortic, or peripheral vascular disease significantly increases CAD risk 1
- Indicates systemic atherosclerotic burden
Chronic Kidney Disease
- Independent risk factor for CAD 1
- Often coexists with hypertension and diabetes
Risk Factor Clustering
- Multiple risk factors frequently occur together, substantially increasing overall risk
- 17% of patients have ≥3 risk factors 1
- Risk assessment should consider global risk factor burden rather than individual factors in isolation
Clinical Implications
- Traditional risk factors are less useful for diagnosing acute ischemia than symptoms, ECG findings, and cardiac biomarkers 1
- However, these risk factors are important for long-term prognosis and treatment decisions
- Risk factor modification remains the cornerstone of primary and secondary prevention
Pitfalls in Risk Assessment
- Risk calculators may overestimate risk in contemporary diverse populations 3
- Older age particularly associated with risk overestimation 3
- Family history may be underreported or unknown
- The "smoker's paradox" and "obesity paradox" can lead to misinterpretation of short-term risk
Understanding these risk factors allows for comprehensive risk assessment and targeted interventions to reduce CAD morbidity and mortality.