What are the possible causes for high cholesterol?
Psaty, Bruce M., T. Lumley, C.D. Furberg, G. Schellenbaum, M. Pahor, M.H. Alderman, and N.S. Weiss. "Health Outcomes Associated with Various Antihypertensive Therapies Used as First-Line Agents: A Network Meta-Analysis." Journal of the American Medical Association. 289:19(2003): 2534-44. 12 Sep. 2008 <http://jama.ama-assn.org/cgi/content/abstract/289/19/2534>.
Stone, Neil J. "Secondary Causes of Hyperlipidemia." The Medical Clinics of North America. 78:1(1994): 117-41. 11 Sep. 2008 <http://www.ncbi.nlm.nih.gov/pubmed/8283927>.
Stone, Neil J. and Conrad B. Blum. Management of Lipids in Clinical Practice. West Islip: Professional Communications, 2006.
Weinbrenner, T., M. Zuger, G.E. Jacoby, S. Herpertz, R. Liedtke, T. Sudhop, I. Gouni-Berthold, M. Axelson, and H.K. Berthold. "Lipoprotein Metabolism in Patients with Anorexia Nervosa: A Case-Control Study Investigating the Mechanisms Leading to Hypercholesterolaemia." British Journal of Nutrition. 91:6(2004): 959-69. 12 Sep. 2008 <http://www.nutritionsociety.org.uk/bjn/091/BJN0910959.htm>.
"What Causes High Blood Cholesterol?" nhlbi.nih.gov. Sep. 2008. National Heart Lung and Blood Institute, Diseases and Conditions Index. National Institutes of Health. 12 Sep. 2008 http://www.nhlbi.nih.gov/health/dci/Diseases/Hbc/HBC_Causes.html
Chances are that high cholesterol levels are usually a result of well-known
factors like:
Genetics,
Diet,
Lack of exercise,
Age and
Gender
But in some cases, high cholesterol levels can be caused by other diseases
or widely prescribed drugs.
Known as secondary or acquired hyperlipidemia, this condition is usually
the result of another disorder that changes a patient's lipid profile.
In addition to the risks just noted, the link between primary and secondary
causes of hyperlipidemia is especially important when
high triglyceride levels occur with certain cases
of acquired hyperlipidemia. In combination, these two conditions can lead to pancreatitis, an inflammation of the pancreas
that is often life threatening.
Illnesses and Acquired Hyperlipidemia
What are the illnesses that can cause acquired hyperlipidemia? "By far
the worst are diabetes and prediabetes. They're the most common lipid
disorders in this country," says Maureen Mays, M.D., assistant professor
of medicine and director of preventative cardiology at Oregon Health and
Science University in Portland, Oregon.
"It's directly related to this country's obesity," she adds. Not
all "bad" cholesterol, or low-density lipoprotein (LDL), particles are the same, Mays explains.
The LDL particles called small, dense LDL particles are recognized as
being more likely to lead to atherosclerosis.
"These people with diabetes, their LDL levels look OK, but they're
not," Mays says. "The pattern you always see (in acquired
hyperlipidemia) is high triglycerides, low HDL and small, dense LDL particles."
In addition to diabetes and prediabetes, illnesses associated with acquired
hyperlipidemia include:
Hypothyroidism (underactive thyroid gland)
Cushing's syndrome (an illness caused by high
levels of the hormone cortisol)
Nephrotic syndrome (a kidney disorder)
Certain endocrine and metabolic disorders
The conditions just listed all affect blood levels of cholesterol and
triglycerides in some way.
In addition to disease, certain drugs and hormonal therapies are associated
with acquired hyperlipidemia and other changes in blood lipid levels:
Estrogen and
corticosteroids can raise the levels of
triglycerides and the "good", or HDL, whereas oral anabolic steroids
will often lower levels of HDL.
Birth control pills can raise cholesterol
levels and increase the risk of atherosclerosis, depending on the type and the
progestin/estrogen dosage.
Beta blockers, a class of drugs that are
prescribed for certain conditions, such as high blood pressure glaucoma and migraines
typically elevate levels of triglycerides while lowering HDL levels.
Retinoids, used to manage conditions like
psoriasis and certain types of skin cancer, are sometimes linked to increases
in LDL and triglyceride levels.
Diuretics are prescribed to reduce the buildup
of excess bodily fluids. The class of diuretics known as thiazide diuretics -- often used to treat high blood
pressure -- has also been associated with increased cholesterol and
triglyceride levels. There is continuing research in this area because some
studies have shown that lower doses of diuretics in combination with other
drugs may have a net benefit in reducing cardiovascular disease.
In most cases, managing the underlying disease, or discontinuing the use of
drugs that are associated with acquired hyperlipidemia, will lead to healthier
cholesterol levels. In other cases, therapies specifically tailored to lower
cholesterol levels may be needed. These may include lifestyle changes, such as exercise and diet,
but in other cases, cholesterol-lowering drugs may be needed.
Failure to treat cases of acquired hyperlipidemia can result in serious
health problems. As Mays points out, "Metabolic or acquired lipid
disorders are actually a higher risk for heart disease than the primary lipid
disorders."
Sources:
Chait, A. and J.D. Brunzell
"Acquired Hyperlipidemia (Secondary Dyslipoproteinemias)." Endocrinology
and Metabolism Clinics of North America. 19:2(1990): 259-78. 10 Sep. 2008
<http://www.ncbi.nlm.nih.gov/pubmed/2192873?dopt=Abstract>.
Feillet, Francois, C. Feillet-Coudray, J.M. Bard, H.J. Parra, E. Favre, B. Kabuth, J.C. Fruchart, and M. Vadailhet. "Plasma Cholesterol and Endogenous Cholesterol Synthesis During Refeeding in Anorexia Nervosa." Clinica Chimica Acta. 294:1-2(2000): 45-56. 12 Sep. 2008 <http://www.ncbi.nlm.nih.gov/pubmed/10727672>.
"Hyperlipidemia -- Acquired." RWJobgyn.org. 2001. Robert Wood Johnson Memorial Hospital. 8 Sep. 2008 <http://www.rwjobgyn.org/Atoz/encyclopedia/article/000403.asp>.
Lemanski, Paul E. "Beyond Routine Cholesterol Testing: The Role of LDL Particle Size Assessment." CDPHP Medical Messenger. May 2004. Center for Preventive Medicine and Cardiovascular Health. 14 Sep. 2008 <http://www.centerforpreventivemedicine.com/04114med_messenger.pdf>.
Mays, Maureen, assistant professor of medicine and director of preventative cardiology, Oregon Health and Science University, Portland, Ore. Telephone interview. 9 Sep. 2008.
Feillet, Francois, C. Feillet-Coudray, J.M. Bard, H.J. Parra, E. Favre, B. Kabuth, J.C. Fruchart, and M. Vadailhet. "Plasma Cholesterol and Endogenous Cholesterol Synthesis During Refeeding in Anorexia Nervosa." Clinica Chimica Acta. 294:1-2(2000): 45-56. 12 Sep. 2008 <http://www.ncbi.nlm.nih.gov/pubmed/10727672>.
"Hyperlipidemia -- Acquired." RWJobgyn.org. 2001. Robert Wood Johnson Memorial Hospital. 8 Sep. 2008 <http://www.rwjobgyn.org/Atoz/encyclopedia/article/000403.asp>.
Lemanski, Paul E. "Beyond Routine Cholesterol Testing: The Role of LDL Particle Size Assessment." CDPHP Medical Messenger. May 2004. Center for Preventive Medicine and Cardiovascular Health. 14 Sep. 2008 <http://www.centerforpreventivemedicine.com/04114med_messenger.pdf>.
Mays, Maureen, assistant professor of medicine and director of preventative cardiology, Oregon Health and Science University, Portland, Ore. Telephone interview. 9 Sep. 2008.
Psaty, Bruce M., T. Lumley, C.D. Furberg, G. Schellenbaum, M. Pahor, M.H. Alderman, and N.S. Weiss. "Health Outcomes Associated with Various Antihypertensive Therapies Used as First-Line Agents: A Network Meta-Analysis." Journal of the American Medical Association. 289:19(2003): 2534-44. 12 Sep. 2008 <http://jama.ama-assn.org/cgi/content/abstract/289/19/2534>.
Stone, Neil J. "Secondary Causes of Hyperlipidemia." The Medical Clinics of North America. 78:1(1994): 117-41. 11 Sep. 2008 <http://www.ncbi.nlm.nih.gov/pubmed/8283927>.
Stone, Neil J. and Conrad B. Blum. Management of Lipids in Clinical Practice. West Islip: Professional Communications, 2006.
Weinbrenner, T., M. Zuger, G.E. Jacoby, S. Herpertz, R. Liedtke, T. Sudhop, I. Gouni-Berthold, M. Axelson, and H.K. Berthold. "Lipoprotein Metabolism in Patients with Anorexia Nervosa: A Case-Control Study Investigating the Mechanisms Leading to Hypercholesterolaemia." British Journal of Nutrition. 91:6(2004): 959-69. 12 Sep. 2008 <http://www.nutritionsociety.org.uk/bjn/091/BJN0910959.htm>.
"What Causes High Blood Cholesterol?" nhlbi.nih.gov. Sep. 2008. National Heart Lung and Blood Institute, Diseases and Conditions Index. National Institutes of Health. 12 Sep. 2008 http://www.nhlbi.nih.gov/health/dci/Diseases/Hbc/HBC_Causes.html
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