Hypercholesterolemia, most commonly known as high cholesterol, is diagnosed when you have too much cholesterol circulating in your blood. When this occurs over time, cholesterol can accumulate on the walls of vessels and create a waxy, thick plaque. This process, known as atherosclerosis, can reduce blood flow to the heart or other areas of the body, preventing oxygen and nutrients from getting where they need to go. If blood flow becomes completely blocked to the heart or brain, it can cause a heart attack or a stroke, respectively.
High cholesterol can come from two main sources: your liver and from your diet. Although dietary recommendations suggest consuming no more than 200 mg of cholesterol a day, our bodies make most of the cholesterol it needs on a daily basis.
The cholesterol that is made by your liver is also known as endogenous cholesterol. High amounts of endogenous cholesterol usually result from certain disease conditions (such as hypothyroidism or diabetes) or from your genes. Sometimes, if you treat the disease state, you may be able to lower your cholesterol levels. But if you have a parent or sibling with high cholesterol levels, there is a chance that you might also get high cholesterol in the future.
Exogenous cholesterol refers to cholesterol that comes from outside of the body. This is usually caused by a diet that it high in cholesterol and saturated fat. Foods in such a diet might include fast foods, pastries, and meats. By reducing the amount of fat and cholesterol you consume daily, you may be able to lower your cholesterol. Some foods are not alone in causing high cholesterol levels -- some medications can cause your cholesterol to be elevated, too.
Source:
Dipiro JT, Talbert RL. Pharmacotherapy: A Pathophysiological Approach, 6th ed 2005.

