People with one or more close relatives who have or had early coronary artery disease (CAD) are at an increased risk of developing CAD for several reasons. A tendency to develop certain risk factors, such as high cholesterol and high blood pressure, may be related to specific inherited genes. Genes are passed on from parent to child and are like the blueprints of the body: They are a code that determines how our bodies are made and how they function.

Inherited lipid disorders can contribute to atherosclerosis and may lead to early CAD. Although family-related behaviors also contribute to the risk of developing CAD, researchers are still working to understand exactly why CAD runs in families.

Behavior or genetics?

In addition to inherited factors, there is probably a large environmental component to the increased risk seen in some families. People who smoke expose their family members to secondhand smoke, increasing the risk of heart disease in their family members. Children of parents who smoke are more likely to smoke than children of nonsmokers. Dietary habits may also play a role. Families who eat fatty diets are more likely to develop CAD than those who eat more balanced diets.

Addressing each of these family-related behaviors may greatly reduce your chance of developing CAD.