HDL and LDL: The 'good' and 'bad' cholesterol myth
Three studies, all published in 2006, really scotched the myths about LDL and HDL. The first, published in the Journal of the American College of Cardiology, was to determine the relationship between established cardiovascular risk factors such as cholesterol, LDL, triglycerides, C-reactive protein, et cetera, and the extent of coronary atherosclerosis.[1]
The most significant finding was that LDL was NOT a predictor of greater disease.
This was confirmed by a joint Canadian and American group who also found that levels of LDL did not predict CHD.[2]
To rub this in, the third research team showed that it was raised levels of HDL which predicted recurrent coronary events in some heart attack patients.[3]
Studying the interaction between LDL, HDL and inflammation in the THROMBO (Postinfarction Thromogenic Factors and Recurrent Coronary Events) study, researchers showed that in a sub-group of patients, only elevated HDL was a significant and independent predictor of risk.
What these studies say, therefore, is that LDL is not 'bad' after all and HDL isn't necessarily 'good'. Which, of course, is the exact opposite of what we have been told for a quarter of a century.
Confirmation of the falsity of the LDL = 'bad' myth became apparent in 2007 with the publication of a study which showed that of 270,655 hospitalizations from 541 hospitals, fully half the patients hospitalised with coronary artery disease had very low LDL levels of less than 100 mg/dL (2.6 mmol/L);[4] and more than one in six had LDL levels below 70 mg/dL (1.8 mmol/L), yet these low levels are supposed to protect against coronary artery disease.
References
1. Nicholls SJ, Murat Tuzcu E, Crowe T, et al. Relationship Between Cardiovascular Risk Factors and Atherosclerotic Disease Burden Measured by Intravascular Ultrasound. J Am Coll Cardiol 2006; 47:1967-1975.
2. Liu J, Sempos CT, Donahue RP, et al. Non-High-Density Lipoprotein and Very-Low-Density Lipoprotein Cholesterol and Their Risk Predictive Values in Coronary Heart Disease. Am J Cardiol 2006; 98: 1363-1368
3. Corsetti JP, Zareba W, Moss AJ, et al. Elevated HDL is a risk factor for recurrent coronary events in a subgroup of non-diabetic postinfarction patients with hypercholesterolemia and inflammation. Atherosclerosis 2006; 187: 191-197.
4. Fonarow GC, Cannon CP, Deedwania PC, et al. Lipid Levels in Patients Hospitalized with Coronary Artery Disease: An Analysis of 136,905 Hospitalizations in GWTG-CAD. http://astute.cardiosource.com/2007/vposters/pdf/275_Fonarow.pdf.
