High blood cholesterol is a condition that causes the levels of certain bad fats, or lipids, to be too high in the blood. The most common cause of high blood cholesterol is an unhealthy lifestyle. However, the genes that you inherit from your parents, other medical conditions, and some medicines may also cause high blood cholesterol.
Causes
Unhealthy lifestyle habits
Unhealthy eating patterns, such as consuming high amounts of saturated fats or trans fats, can increase bad low-density lipoprotein cholesterol (LDL cholesterol).
Lack of physical activity, such as spending a lot of time during the day sitting and watching TV or using the computer, is linked with lower levels of good high-density lipoprotein cholesterol (HDL cholesterol).
Smoking lowers HDL cholesterol, particularly in women, and increases LDL cholesterol.
Genes
Some people may develop high blood cholesterol because of mutations, or changes, in their genes. These mutations make it harder for the body to clear LDL cholesterol from the blood or break it down in the liver. Familial hypercholesterolemia is one inherited form of high blood cholesterol.
Other medical conditions
The following medical conditions may cause high blood cholesterol:

Inflammatory diseases such as psoriasis, lichen planus, pemphigus, histiocytosis, lupus erythematosus, and rheumatoid arthritis
Medicines
Some medicines that you take for other medical conditions can increase your cholesterol. Examples of these medicines include the following:
Diuretics such as thiazide that are used for high blood pressure
Immunosuppressive drugs such as cyclosporine that are used to treat inflammatory diseases such as psoriasis or to prevent rejection after a transplant
Steroids such as prednisone that are used to treat inflammatory diseases such as lupus and psoriasis
Retinoids such as retinol that are used to treat acne
Antiretroviral medicines used to treat HIV
Antiarrhythmic medicines such as amiodarone that are used in treatment for irregular rhythm of the heart
Screening and Prevention
A lipid panel will measure the total cholesterol, high-density lipoprotein (HDL) cholesterol, and non-high-density lipoprotein (non-HDL) cholesterol levels in your blood. Non-HDL cholesterol includes low-density lipoprotein (LDL) cholesterol and is calculated by subtracting your HDL cholesterol levels from your total cholesterol levels. See the table below to learn whether you have healthy blood cholesterol levels based on your age and sex.

Complications
High blood cholesterol levels lead to atherosclerosis, or the buildup of plaque deposits in blood vessels throughout the body. Over time, chronic or uncontrolled high blood cholesterol can cause serious complications including the following:
Coronary heart disease, including angina or heart attack
Treatment
High blood cholesterol is treated with heart-healthy lifestyle changes and medicines to control or lower your high blood cholesterol. Lipoprotein apheresis is a procedure that can be used to treat familial hypercholesterolemia.
Heart-healthy eating. As recommended in the 2015–2020 Dietary Guidelines for Americansexternal link, heart-healthy eating includes limiting the amount of saturated and trans fats that you eat. It also includes consuming fish high in omega-3 fatty acids and vegetable oils that can help lower blood cholesterol levels and the risk of cardiovascular disease. The Therapeutic Lifestyle Changes diet and the DASH Eating Plan can help you lower your bad low-density lipoprotein (LDL) cholesterol. These plans also encourage eating whole grains, fruits, and vegetables rather than refined carbohydrates such as sugar. Talk to your doctor about other nutritional changes that you can make.
Being physically active. There are many health benefits to being physically active and getting the recommended amount of physical activity each week. Studies have shown that physical activity can lower LDL cholesterol and triglycerides and increase good high-density lipoprotein (HDL) cholesterol. Before starting any exercise program, ask your doctor what level of physical activity is right for you.
Aiming for a healthy weight. If you have high blood cholesterol and are overweight or obese, you can improve your health by aiming for a healthy weight. Research has shown that adults with overweight and obesity can reduce LDL cholesterol and increase HDL cholesterol by losing only 3 percent to 5 percent of their weight. Achieving 5 percent to 10 percent weight loss in 6 months is recommended.
Managing stress. Research has shown that chronic stress can sometimes increase LDL cholesterol levels and decrease HDL cholesterol levels.
Quitting smoking. Visit Smoking and Your Heart and the National Heart, Lung, and Blood Institute's Your Guide to a Healthy Heart.
Would like to find out more about this article? Please visit the following link:
https://www.nhlbi.nih.gov/health-topics/high-blood-cholesterol