From the Guidelines
Family history of myocardial infarction (MI) is a significant non-modifiable risk factor for cardiovascular disease, and individuals with a first-degree relative who experienced an MI before age 55 for males or before age 65 for females should be considered at higher risk. This risk factor should be documented in the medical record and considered when assessing the overall cardiovascular risk profile 1. The increased risk from family history likely stems from both genetic factors affecting lipid metabolism, blood pressure regulation, and inflammatory responses, as well as shared environmental and lifestyle factors within families.
Key considerations for individuals with a family history of MI include:
- Managing modifiable risk factors through lifestyle changes, such as regular physical activity, a heart-healthy diet, avoiding tobacco products, limiting alcohol consumption, and maintaining a healthy weight
- Regular screening for other cardiovascular risk factors like hypertension, diabetes, and dyslipidemia, typically starting at age 20 and continuing throughout life
- Potential for more aggressive preventive measures, including earlier or more frequent screening, and possibly preventive medications like statins, depending on the overall risk assessment 1
It is essential to note that the reliability of self-reported family history is imperfect, and recall bias may be a concern 1. However, family history modestly improves risk stratification, and its inclusion in risk assessment models can aid in reclassifying individuals, particularly those at intermediate risk 1.
In clinical practice, taking a detailed family history of cardiovascular disease at initial encounters and updating it at each non-urgent health encounter is recommended, especially for individuals with a positive family history or cardiovascular risk factors 1. This information can be used to stratify risk for cardiovascular disease and guide preventive measures.
From the Research
Family History of Myocardial Infarction (MI)
- A family history of MI is a significant risk factor for both MI and venous thromboembolism (VTE) 2
- The risk of MI increases with the number of first-degree relatives affected, with a relative risk of 2.0 for those with one relative and 3.0 for those with two or more relatives affected 3
- A detailed family history, including the number of affected first- and second-degree relatives, contributes to risk assessment, especially in middle-aged persons 4
- Family history of coronary heart disease interacts with other cardiovascular risk factors, such as smoking, high cholesterol, and diabetes, to increase the risk of MI 3, 5
Risk Assessment
- The incidence rate ratio (IRR) for MI increases with the number of affected relatives, ranging from 1.46 for those with one first-degree relative to 3.58 for those with three or more first-degree relatives 4
- A family history of MI is an independent risk factor for MI, with an adjusted odds ratio of 2.0 for men and 2.1 for women reporting one or more affected parents or siblings 5
- The association between family history and MI is partially explained by the clustering of established and newly-identified risk factors, such as lipids, lipoproteins, and genetic risk factors 6
Interactions with Other Risk Factors
- Family history of coronary heart disease interacts synergistically with other cardiovascular risk factors, such as smoking and high cholesterol, to increase the risk of MI 5
- The effect of family history on the risk of MI is approximately multiplicative for several variables, including smoking, serum cholesterol, hypertension, and hyperlipidemia 3
- Diabetes and body mass index do not interact with family history to increase the risk of MI 3