According to the American Heart Association, a blood cholesterol level of less than 160 milligrams per deciliter is considered low. Taking cholesterol-lowering medications occasionally leads to low cholesterol, also called hypocholesterolemia. Several disorders and conditions also cause hypocholesterolemia. Opinions differ as to whether the condition is harmful in an otherwise healthy adult.
Hypocholesterolemia manifests as a low total blood cholesterol level. This may be referred to as low total serum cholesterol. A low LDL cholesterol level and low triglyceride level may also be present. HDL cholesterol may be absent, low, normal or elevated. For some patients, lab work may be the only indicator for hypocholesterolemia. According to an abstract presented at the 2000 International Conference on AIDS, depressed mood is correlated with a blood cholesterol level below 150 milligrams per deciliter in patients with HIV disease who use illicit drugs. A study published in the 2002 issue of "European Archives of Psychiatry and Clinical Neuroscience" found that "fasting serum cholesterol levels are low in manic patients, especially during mixed bipolar episodes." One variation of low cholesterol, known as Tangier Disease, has a symptom of orangish-yellow tonsils. The sufferer also has an enlarged liver and spleen.
Causes of Primary Hypocholesterolemia
If you have "primary hypocholesterolemia," it means that you have a disorder that has the effect of lowering your cholesterol. One type of primary hypocholesterolemia is Tangier disease. It is a genetic disorder characterized by a low or absent HDL cholesterol level and a low total cholesterol level. A second type is familial hypobetalipoproteinemia, a genetic disorder characterized by a low total cholesterol level, low LDL cholesterol level, normal HDL cholesterol level and low triglyceride level. Another type is abetalipoproteinemia, which is a genetic disorder characterized by a low total cholesterol level and low triglyceride level. Each of these disorders is rare.
Causes of Secondary Hypocholesterolemia
If you have "secondary hypocholesterolemia," it means that you have another disorder that in turn causes your cholesterol level to be low. Common examples of secondary hypocholesterolemia include hyperthyroidism, anemia, various liver diseases, chronic infection, HIV or AIDS and malnutrition, according to the Journal of Peking University Health Sciences.
What to Do if You Have Low Blood Cholesterol
If your blood cholesterol level is low, discuss the possible reasons with your physican. She may conduct testing to rule out a primary or secondary undiagnosed disorder. If you are taking cholesterol-lowering medications, the physician may lower the dosage or change the medication. If you feel that your mood is impaired, seek medical advice.