Definition of Premature Atherosclerotic Heart Disease
Premature atherosclerotic heart disease is defined as coronary artery disease occurring before age 55 years in men and before age 65 years in women, particularly when it affects first-degree relatives. 1
Standard Age Thresholds
- Men: Disease onset before age 55 years constitutes premature coronary heart disease 1
- Women: Disease onset before age 65 years constitutes premature coronary heart disease 1
- These age cutoffs are consistently applied across major cardiovascular guidelines when defining family history as a risk-enhancing factor 1
Clinical Context and Significance
When evaluating family history, the presence of a first-degree relative (parent, sibling, or child) with coronary heart disease meeting these age criteria significantly elevates an individual's cardiovascular risk by 1.5- to 2.0-fold, independent of other traditional risk factors 1
- Almost 75% of patients with premature CHD have a positive family history, demonstrating the strong hereditary component and opportunities for early prevention 1
- The risk increases further with younger age of onset in the affected relative, increasing numbers of affected relatives, and closer genealogical proximity 1
Alternative Definitions in Specific Contexts
For younger populations, some recent research defines premature CAD more stringently:
- Age ≤45 years is used in studies examining particularly early-onset disease in young adults 2
- Age 20-40 years represents an ultra-premature subset, often lacking traditional risk factors entirely 3
- Men aged <55 years and women aged <65 years remains the broader epidemiologic definition used in contemporary research 4, 5
Subclinical Disease Definition
For coronary artery calcium scoring, premature advanced atherosclerosis is defined as:
- CAC score ≥90th percentile for age, sex, and race in younger individuals, which represents accelerated atherosclerotic burden 6
- The presence of any detectable CAC in patients under age 50 years is associated with 5-fold increased coronary events and 3-fold increased cardiovascular events 7
Risk Stratification Implications
The premature designation triggers specific clinical actions:
- Risk factor screening should be performed in all first-degree relatives of patients developing CHD before age 55 (men) or 65 (women) 1
- Multifactorial cardiovascular risk will be higher than estimated from standard risk calculators in these individuals 1
- When familial hypercholesterolemia is suspected (family history of premature CHD plus cholesterol ≥8.0 mmol/L), screening all first-degree relatives with full lipoprotein profiles is essential 1