Consequences of High Cholesterol

For nearly 60 years, doctors have known about the link between cholesterol and heart disease.

The consequences of high cholesterol can be serious. Most notably, high cholesterol raises the risk of heart disease -- there is wide agreement in the medical community on this point. The relationship was first underscored by the pioneering Framingham Heart Study.

Since 1948, that study has monitored 5,209 men and women for the development of coronary heart disease. Data from this and other studies were joined in a report, which showed that the risk for coronary heart disease increases as blood-cholesterol level rises, especially as it rises past 200 mg/dL.

These high levels of blood cholesterol directly contribute to atherosclerosis and heart attack. Low HDL cholesterol and high levels of triglycerides are also factors of the metabolic syndrome, a condition that increases the risk of coronary heart disease.

We'll start out taking a look at the more high-profile condition. The next page describes the series of events that start with atherosclerosis and can end in a heart attack.

For more information on cholesterol, check out these links:

  • Cholesterol Levels: We all know there's "good" and "bad" cholesterol. Find out why you need more of one kind of cholesterol and less of the other.
  • Causes of High Cholesterol: Diet and DNA are the main causes of high cholesterol. Learn why the numbers might be high in your case.
  • How to Lower Cholesterol: Like many conditions, eating right and exercising can help control cholesterol. Learn what that means for you.
  • How Cholesterol Works: Cholesterol is essential for the body. Find out why we need it and how much is too much.
  • Understanding a Heart Attack: Heart attack is the No. 1 cause of death in the U.S. Find out what happens in a heart attack.

This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.

Atherosclerosis and Heart Attack

If enough cholesterol is deposited in the blood, clots can eventually clog the arteries and cause a heart attack.

Atherosclerosis is the condition in which the inner layers of the artery wall, known as the intima, become thick and irregular due to deposits of fats (mainly in the form of cholesterol and another fat called a phospholipid) and other substances. Atherosclerosis can develop in different parts of the body, but when deposits occur in the arteries that supply blood to the heart, the condition is specifically called coronary atherosclerosis. As the buildup grows, the artery narrows and the flow of blood to the heart muscle is reduced.

Like any other muscle, the heart needs blood to provide it with oxygen. When that blood flow is reduced or completely blocked, some of the cells in the heart muscle can suffocate and die.

Atherosclerosis does not occur overnight. In most cases, the fatty buildups that can narrow the artery develop "silently" over decades. Pathologists divide the telltale signs of atherosclerosis into two major types--the earliest deposits, called fatty streaks, and the advanced deposits, called plaques.

Fatty streaks, which contain about 25 percent fat, can be seen even in the arteries of children. During the development of fatty streaks, the cells that line the arteries are stimulated to take in more cholesterol than they can handle. Although this process is not completely understood, it may begin when damage occurs to the endothelium, the thin layer of cells lining the inside of the artery.

Several factors are suspected of causing this damage, including cigarette smoking and high blood pressure. The key process, however, is a chemical change in LDL whereby LDL is oxidized. LDL becomes oxidized when free radicals, a form of oxygen that has been chemically modified into a highly unstable substance, encounter LDL. This stimulates atherosclerosis in several ways.

First, oxidized LDL is toxic to the walls of the arteries and encourages further injury. Second, it sends out chemical distress signals that cause more blood cells--called monocytes--to flock to the artery. The monocytes then penetrate the endothelium, where they try to "clean up" the problem by swallowing the oxidized LDLs.

Unfortunately, as they swallow the damaged LDLs, the monocytes themselves begin to swell within the endothelium. This sets up a vicious cycle in which the response of the body to this injury both starts and continues the process of building the cholesterol-engorged plaques.

The earliest visible deposits are called fatty streaks, which are present to some extent in all of us. But fatty streaks alone do not obstruct the flow of blood. They become a problem in people who have poor eating habits, which causes the fatty streaks to grow into dangerous and potentially deadly cholesterol-rich plaques.

Plaque is the hallmark of coronary atherosclerosis. It forms as more and more cholesterol is deposited at the site of the fatty streak. A simple plaque can grow into a complicated one when calcium accumulates and hardens the plaque and when blood clots develop.

Clots are a particularly feared complication; if the cap, or covering, of the fibrous plaque tears or ruptures, heavy bleeding occurs. This causes a local clot called a thrombus, which can obstruct the artery and cause a heart attack (also known as a coronary thrombosis). During a heart attack, the blood supply is cut off from a portion of the heart muscle, and that area of the heart dies. If enough of the heart is affected, or if the heart begins to beat rapidly and uncontrollably (called arrhythmia), the victim can die.

When the plaque grows more slowly, it may eventually reduce blood flow through the coronary arteries. If an artery is narrowed to 30 percent or less of its normal diameter, the situation is clinically described as angina, a pain or discomfort in the chest or shortness of breath. Angina usually occurs during a time of exertion, when the heart requires more oxygen than it needs while the body is at rest.

Not all those suffering from threatening heart disease experience the relatively mild warning of angina, however. Sometimes the first sign of heart disease is a full-blown heart attack.

And some consequences of cholesterol are less severe but unhealthy nonetheless. One such condition, metabolic syndrome, is detailed on the next page.

For more information on cholesterol, see:

  • Cholesterol Levels: We all know there's "good" and "bad" cholesterol. Find out why you need more of one kind of cholesterol and less of the other.
  • How Cholesterol Works: Cholesterol is essential for the body. Find out why we need it and how much is too much.

This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.

Metabolic Syndrome

Abdominal obesity, along with low levels of "good" HDL cholesterol, are two of the contributing factors to metabolic syndrome.

Metabolic syndrome is characterized by several risk factors, including abdominal obesity, low levels of HDL cholesterol, and elevated levels of triglycerides, blood pressure, and fasting blood glucose. According to the National Cholesterol Education Program (NCEP), three or more of these risk factors renders a diagnosis of the metabolic syndrome.

Although genetic tendencies toward the metabolic syndrome may be present, it is primarily a consequence of a poor diet, sedentary lifestyle, and the resulting excess weight gain in childhood and/or throughout adulthood. Lifestyle, then, heavily influences the severity of the metabolic syndrome. The modern American diet certainly doesn't create the picture of health.

Americans tend to consume more excess calories from fat and dietary cholesterol than other countries where the rate of coronary disease is much less. Portion sizes have increased dramatically over the past decade, and many Americans don't balance this increased calorie intake with a needed boost in physical activity -- a crucial factor resulting in an increase in metabolic syndrome.

Now that you know cholesterol can cause more than heart disease, you have that much more reason to get off the couch, have fun exercising, and stay healthy.

For more information on cholesterol, check out these links:

  • Cholesterol Levels: We all know there's "good" and "bad" cholesterol. Find out why you need more of one kind of cholesterol and less of the other.
  • Causes of High Cholesterol: Diet and DNA are the main causes of high cholesterol. Learn why the numbers might be high in your case.
  • How to Lower Cholesterol: Like many conditions, eating right and exercising can help control cholesterol. Learn what that means for you.
  • How Cholesterol Works: Cholesterol is essential for the body. Find out why we need it and how much is too much.
  • Understanding a Heart Attack: Heart attack is the No. 1 cause of death in the U.S. Find out what happens in a heart attack.

ABOUT THE AUTHOR

Dr. Neil Stone is a professor of clinical medicine in cardiology at the Feinberg School of Medicine of Northwestern University and a practicing internist-cardiologist-lipidologist at Northwestern Memorial Hospital. He also serves as the Medical Director of the Vascular Center for the Bluhm Cardiovascular Institute. Dr. Stone was a member of the first and third National Cholesterol Education Program Adult Treatment Panels and a past chairman of the American Heart Association Nutrition Committee and Clinical Affairs Committee.

This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.