Question

#Increased serum levels of which of the following may be associated with a decreased risk of atherosclerosis?

-Very low-density lipoproteins (VLDL)

-Low-density lipoproteins (LDL)

-Intermediate - density lipoproteins (IDL)

-High-density lipoproteins (HDL)

- Cholesterol

Answer 1

• Blood levels of HDL are inversely related to risk of coronary artery disease, and it was thought that low HDL levels represented an independent risk factor. 
• This led to a concerted effort to identify treatments that might prevent CAD by raising HDL concentrations. 
• This area has been very controversial, but recent evidence suggests that although low HDL is inversely correlated with risk of CAD, the relationship is not causal. 
• In other words, low HDL levels are a marker for other factors that cause progression of CAD. Several pieces of evidence suggest this.
• Genetic variants that are associated with high HDL levels are not consistently associated with a reduced risk of CAD. 
• In fact, the same study that found that SNPs associated with high LDL were consistently associated with increased risk failed to show that SNPs associated with HDL had any relationship to risk of CAD. 
• These authors also reported that a genetic variant that specifically and substantially increases plasma HDL cholesterol, did not reduce risk of myocardial infarction.
• Drugs that raise HDL levels do not reduce the risk of CAD.