What Is Normal HDL?
High cholesterol is a major risk factor for developing heart disease, the leading cause of death in the United States. The Centers for Disease Control and Prevention estimate that over one-third of American adults have high cholesterol. Regular cholesterol testing is essential to identify this serious health condition because of the lack of symptoms.
A cholesterol test measures total cholesterol, LDL or bad cholesterol, and HDL or good cholesterol. HDL is generally considered good because it helps the body control total cholesterol levels. Optimal HDL is 60 mg/dL and above. If your HDL is below 40 mg/dL, you are considered at risk for developing heart disease.
When Good Goes Bad
Unfortunately, the question of good or bad cholesterol is not cut and dry. A 2011 statistical analysis by Tachikawa Medical Center Nagacho in Japan found a positive association between high blood pressure and high HDL. Ironically, high blood pressure or hypertension is also a risk factor for heart disease.
One explanation may be how the body processes HDL. Though the exact mechanism is not fully understood, a 2011 study by the Thrombosis Research Institute in India found that HDL can morph into an abnormal form that is associated with pro-inflammatory activity.
Under normal circumstances, the body fights infection or injury through the inflammatory response by the immune system. White blood cells and other cells called macrophages attack invading bacteria and initiate the healing process. You may experience swelling and redness at the site of an infected wound as your body goes through this process.
However, some things can trigger a chronic response where the body continues the inflammatory response beyond what is needed. Chronic inflammation is associated with several health conditions including atherosclerosis, diabetes mellitus and celiac disease. Abnormal HDL may pose risks for vulnerable individuals.
Excessively high HDL cholesterol also carries health risks. A 2010 study by the University of Rochester Medical Center in New York found that high HDL levels increase the risk for a second heart attack in some heart disease patients. Researchers believe the risk may be linked to HDL and the inflammatory characteristics that genetics may influence.
These data suggest that HDL and its effects are more complex when other factors are taken into account. Genetics and the environment are wild cards which prevent a one-size-fits-all solution. This is not to say that excessively high HDL cholesterol is always bad, however, it does illustrate the need for treatment regimes specific to the patient.
To control you risk of heart disease, you can concentrate on the factors which you can control such as exercise and a healthy diet. Taking this course will help improve your quality of life and reduce your risk of developing other chronic health conditions.
Centers for Disease Control and Prevention: Vital Signs: Prevalence, Treatment, and Control of High Levels of Low-Density Lipoprotein Cholesterol — United States, 1999–2002 and 2005—2008 cdc.gov
J. Corsetti, et al. Cholesteryl Ester Transfer Protein Polymorphism (TaqIB) Associates With Risk in Postinfarction Patients With High C-Reactive Protein and High-Density Lipoprotein Cholesterol Levels. Arteriosclerosis, Thrombosis, and Vascular Biology; May 2010; 30:1657.
G. HB, et al. Friend Turns Foe: Transformation of Anti-Inflammatory HDL to Proinflammatory HDL during Acute-Phase Response. Cholesterol, November 2010; 2011:274629. Epub.
Linus Pauling Institute: Inflammation lpi.oregonstate.edu
E. Oda and R. Kawai. High-density lipoprotein cholesterol is positively associated with hypertension in apparently healthy Japanese men and women. British Journal of Biomedical Science, March 2011; 68(1):29-33.
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