High Blood Cholesterol Causes

Cholesterol and other lipids are transported throughout the bloodstream inside lipoproteins, which are a combination of a lipid and protein. Triglycerides are another type of lipid that circulates in the bloodstream inside lipoproteins.

The following lipoproteins are used to predict if a person is at risk of developing heart disease or stroke due to atherosclerosis:

• Low-density lipoprotein (LDL) cholesterol
  LDL cholesterol ("bad" cholesterol) builds up in the walls of the arteries, making them hard and narrow. High blood levels of LDL cholesterol are associated with an increased risk of heart disease and stroke.
• High-density lipoprotein (HDL) cholesterol
  HDL cholesterol ("good cholesterol") carries cholesterol from the body back to the liver, which removes cholesterol from the body. High levels of HDL cholesterol are associated with a decreased risk of heart disease and stroke.
• Triglycerides
  Triglycerides are another type of lipid that can be made in the body or be obtained from food. The body uses triglycerides as a source of energy. High blood levels of triglycerides are also associated with an increased risk of heart disease and stroke.
• Total cholesterol
  Total cholesterol is the sum of the different types of cholesterol in a person's blood.

High blood cholesterol is sometimes called:

• Hypercholesterolemia (high blood cholesterol)
• Hyperlipidemia (high blood lipids)
• Hyperlipoproteinemia (high blood lipoproteins)
• Hypertriglyceridemia (high blood triglycerides)

Contributing risk factors

People may have unhealthy blood lipid levels due controllable risk factors (such as their diet or weight) or uncontrollable risk factors (such as their age or another medical condition). Controllable risk factors usually can be managed through lifestyle changes alone. Uncontrollable risk factors may also require medications to lower LDL cholesterol and triglyceride levels, and raise HDL cholesterol levels.

Controllable risk factors

• High-fat diets
  High sources of dietary LDL cholesterol include eggs, meat, milk products, and shellfish. The following types of dietary fats can raise a person's LDL cholesterol levels:
  
  • Saturated fats are solid at room temperature and usually of animal origin. They are the primary dietary cause of high LDL cholesterol levels.
  • Trans fatty acids (trans fats) are produced by the partial hydrogenation of vegetable oils to harden it into a solid form. They also raise LDL cholesterol levels.
• High-carbohydrate diets
  Diets high in simple carbohydrates (especially simple sugars and starches) raise triglyceride levels.
• Physical activity
  Regular exercise helps people lower their LDL cholesterol and triglyceride levels.
• Medications
  An adverse side effect of the following medications is that they sometimes cause people to develop unhealthy blood lipid levels. People taking these medications for another medical condition may need to have their blood lipid levels tested regularly.
  
  • Beta-blockers treat high blood pressure, heart disease, and migraine headaches.
  • Birth control pills and hormone replacement therapy.
  • Corticosteroids reduce inflammation.
  • Diuretics reduce the amount of water in the body.
• Central obesity
  Central obesity occurs when a person's primary body fat is located around the abdomen and upper body. People with central obesity a have higher incidence of heart disease, high blood pressure, high lipid levels, and type 2 diabetes. Losing weight can significantly lower a person's risk of developing these conditions.
• Alcohol
  Regular or excessive alcohol use may raise LDL cholesterol and triglyceride levels.
• Smoking
  High cholesterol levels and smoking both narrow blood vessels. Although smoking doesn't cause high cholesterol, it increases the risk of developing heart disease for people with high cholesterol. According to the American Heart Association, a smoker's risk of developing heart disease is 2 to 4 times that of nonsmokers.

Uncontrollable risk factors

• Heredity
  High levels of LDL cholesterol and triglycerides can run in families. The most common inherited form of high cholesterol is called familial hypercholesterolemia. People with this condition have elevated LDL cholesterol levels at birth and may develop heart attacks at an early age.
• Medical conditions
  The following medical conditions may alter a person's blood lipid levels. In many cases, treating the condition helps lower the elevated lipid levels.
  
  • Cushing syndrome occurs when a person's body produces too much cortisol (hormone) or when a person takes too much cortisol or other steroid hormones.
  • Diabetes occurs when the body produces little or no insulin, or becomes resistant to insulin.
  • Hypothyroidism causes the thyroid gland to produce low levels of thyroid hormone.
  • Kidney failure causes waste products and fluids to remain in the blood instead of being excreted in the urine.
• Sexand age
  Starting at puberty, men have lower HDL cholesterol levels than women. Younger women have lower LDL cholesterol levels than men. As women and men get older, their LDL cholesterol levels rise. After menopause, women typically have higher LDL cholesterol levels than men.

Complications

The following conditions are complications of untreated high HDL cholesterol and triglyceride levels:

• Atherosclerosis
  Atherosclerosis is the narrowing and thickening of the arteries caused by a build up of LDL cholesterol plaques on the inner walls of the arteries.
• Coronary artery disease
  Coronary artery disease is the narrowing or thickening of the blood vessel walls in the heart due to atherosclerosis. A heart attack results if the blood flow to the heart becomes blocked.
• Heart disease
  Heart disease is any disorder of the heart and its ability to circulate blood throughout the body, such as coronary artery disease, angina, heart attack, heart failure, and arrhythmia.
• Stroke
  Stroke or (cerebral vascular disease) is due to an interruption in the blood flow to the brain.
• Peripheral vascular disease
  Peripheral vascular disease is a narrowing of the blood vessels in a person's extremities, usually the legs and feet.