The exact cause of atherosclerosis isn't known. However, certain traits, conditions, or habits may raise your risk for the disease. These conditions are known as risk factors. The more risk factors you have, the more likely it is that you'll develop atherosclerosis.
                
You can control most risk factors and help prevent or delay atherosclerosis. Other risk factors can't be controlled.
                
Major Risk Factors
                
Unhealthy blood cholesterol levels. This includes high LDL cholesterol (sometimes called "bad" cholesterol) and low HDL cholesterol (sometimes called "good" cholesterol).
                
High blood pressure. Blood pressure is considered high if it stays at or above 140/90 mmHg over time. If you have diabetes or chronic kidney disease, high blood pressure is defined as 130/80 mmHg or higher. (The mmHg is millimeters of mercurythe units used to measure blood pressure.)
                
Smoking. Smoking can damage and tighten blood vessels, raise cholesterol levels, and raise blood pressure. Smoking also doesn't allow enough oxygen to reach the body's tissues.
                
Insulin resistance. This condition occurs if the body can't use its insulin properly. Insulin is a hormone that helps move blood sugar into cells where it's used as an energy source. Insulin resistance may lead to diabetes.
                
Diabetes. With this disease, the body's blood sugar level is too high because the body doesn't make enough insulin or doesn't use its insulin properly.
                
Overweight or obesity. The terms "overweight" and "obesity" refer to body weight that's greater than what is considered healthy for a certain height.
                
Lack of physical activity. A lack of physical activity can worsen other risk factors for atherosclerosis, such as unhealthy blood cholesterol levels, high blood pressure, diabetes, and overweight and obesity.
                
Unhealthy diet. An unhealthy diet can raise your risk for atherosclerosis. Foods that are high in saturated and trans fats, cholesterol, sodium (salt), and sugar can worsen other atherosclerosis risk factors.
                
Older age. As you get older, your risk for atherosclerosis increases. Genetic or lifestyle factors cause plaque to build up in your arteries as you age. By the time you're middle-aged or older, enough plaque has built up to cause signs or symptoms. In men, the risk increases after age 45. In women, the risk increases after age 55.
                
Family history of early heart disease. Your risk for atherosclerosis increases if your father or a brother was diagnosed with heart disease before 55 years of age, or if your mother or a sister was diagnosed with heart disease before 65 years of age.
                
Although age and a family history of early heart disease are risk factors, it doesn't mean that you'll develop atherosclerosis if you have one or both. Controlling other risk factors often can lessen genetic influences and prevent atherosclerosis, even in older adults.
                
Studies show that an increasing number of children and youth are at risk for atherosclerosis. This is due to a number of causes, including rising childhood obesity rates.
                
Emerging Risk Factors
                
Scientists continue to study other possible risk factors for atherosclerosis.
                
High levels of a protein called C-reactive protein (CRP) in the blood may raise the risk for atherosclerosis and heart attack. High levels of CRP are a sign of inflammation in the body.
                
Inflammation is the body's response to injury or infection. Damage to the arteries' inner walls seems to trigger inflammation and help plaque grow.
                
People who have low CRP levels may develop atherosclerosis at a slower rate than people who have high CRP levels. Research is under way to find out whether reducing inflammation and lowering CRP levels also can reduce the risk for atherosclerosis.
                
High levels of triglycerides (tri-GLIH-seh-rides) in the blood also may raise the risk for atherosclerosis, especially in women. Triglycerides are a type of fat.
                
Studies are under way to find out whether genetics may play a role in atherosclerosis risk.
                
Other Factors That Affect Atherosclerosis
                
Other factors also may raise your risk for atherosclerosis, such as:
                
Sleep apnea. Sleep apnea is a disorder that causes one or more pauses in breathing or shallow breaths while you sleep. Untreated sleep apnea can raise your risk for high blood pressure, diabetes, and even a heart attack or stroke.
                
Stress. Research shows that the most commonly reported "trigger" for a heart attack is an emotionally upsetting event, especially one involving anger.
                
Alcohol. Heavy drinking can damage the heart muscle and worsen other risk factors for atherosclerosis. Men should have no more than two drinks containing alcohol a day. Women should have no more than one drink containing alcohol a day.