Most of us in our forties and fifties have at one time or another gone through lipid profile testing ordered by our physician.
This could have been recommended to us either due to certain medications we were prescribed for a few years to treat conditions such as hypertension, diabetes, tobacco abuse, etc.
It may have been because we were seeking help with weight issues, or because the doctor wanted to assess our risk of developing coronary heart diseases later in life.
So what does the lipid profile testing do? Quite simply, it is a group of tests that determines total cholesterol, high density ipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and triglycerides circulating in our blood.
Together, they indicate our risk of getting a heart attack or a stroke due to blockages or hardening of the artery. (1)
Until recently, we were told by doctors that HDL-C was "good cholesterol" and having a higher count (a reading of 60 mg/dL and above) was something that was desirable and would protect our heart from diseases.
HDL-C actually is the cholesterol contained in the HDL particles (HDL-P).
HDL-P is believed to have the ability to remove cholesterol from within arteries and transport it back to the liver for excretion or re-utilization. Conversely having a higher LDL and/or triglyceride count meant we were more likely to have issues of the heart in the future (2).
However, recent studies that tried to raise HDL–C in some people to prevent future heart incidences failed to deliver results. This perplexed the scientific community and threw up some unanswered questions.
New research conducted at Brigham and Women's Hospital, the University of Pittsburgh Graduate School of Public Health and other institutions, have now discovered that measuring HDL particles (HDL-P) and not HDL cholesterol (HDL-C) is a more relevant and precise indicator of coronary heart disease and offers stronger protection than HDL-C.
Tests such as the nuclear magnetic resonance (NMR), the vertical auto profile and gel electrophoresis can measure the HDL-P count accurately. (3)
According to Rachel Mackey, Ph.D., principal investigator of the study and assistant professor of epidemiology at GSPH, “Several recent failures of HDL-raising drugs and a genetic study have generated doubt that circulating levels of HDL in the blood are causally related to heart disease, and that raising HDL is a promising therapeutic approach”. (4)
Why is HDL-P a better indicator than HDL-C for coronary heart diseases?
Samia Mora, M.D., a physician in the Brigham and Women’s Hospital Cardiovascular Division and senior author of the paper said, “HDL cholesterol is only one property of HDL particles. It’s like cargo on a ship; one can look at HDL cholesterol, which is one type of the cargo that is carried on the ship, or one can look at the number of ships.” (5)
The routine evaluation of lipids in our blood only determine in quantitative terms the total HDL-C and LDL-C content inside of their respective lipoprotein fraction.
However, it must be noted that the particles of HDL and LDL (i.e. HDL-P and LDL-P) vary in the amount of cholesterol they carry. So determining the concentration of lipoprotein particles might be a better way to predict coronary incidences for a person than counting the total cholesterol load of HDL or LDL in the particles.
The study has indicated that it is important to not only measure HDL-C, but to experiment with other ways of measurement, such as HDL particles or HDL-P.
SOURCE:
1. Lipid Profile; Lab Tests Online; Web August 2012;
http://labtestsonline.org/understanding/analytes/lipid/tab/glance
2. Understanding Your Cholesterol Test Results; WebMD; Web August 2012;
http://www.webmd.com/cholesterol-management/cholesterol-tests-understand-your-results
3. Revolutionary Cholesterol Tests Coming; Newsmax.com; Web August 2012;
http://archive.newsmax.com/archives/articles/2007/3/9/114402.shtml
4. Measuring HDL Particles as Opposed to HDL Cholesterol Is a a Better Indicator of Coronary Heart Disease, Study Suggests; Science Daily News; Web August 2012;
http://www.sciencedaily.com/releases/2012/07/120711210058.htm
5. Research Spotlight - GSPH Assistant Professor Leads National Study That Offers Insight on Doubts About the "Good" in "Good Cholesterol"; Epidemiology Data Center - Graduate School of Public Health University of Pittsburgh; Web August 2012;
http://www.edc.pitt.edu/researchspotlight_2012_7_11.aspx
Technical report of this study may be accessed at:
1. High-Density Lipoprotein Particle Number; A Better Measure to Quantify High-Density Lipoprotein? Journal of the American College of Cardiology (JACC); Web August 2012;
http://content.onlinejacc.org/article.aspx?articleid=1214574
Reviewed September 19, 2012
by Michele Blacksberg RN
Edited by Jody Smith