LDL cholesterol levels

LDL cholesterol, commonly called "bad cholesterol," is a fat that circulates in the blood, moving cholesterol through the body to where it is needed for cell repair and depositing it on the inside of artery walls.

LDL cholesterol or low-density lipoprotein cholesterol is a lipoprotein whose function is to transport cholesterol to the cells where it exerts its function. It is estimated that LDL cholesterol transports about 60-70% of total serum cholesterol. It differs from other types of cholesterol transporters such as HDL in that its density is lower.

It is often referred to as "bad cholesterol" because when LDL cholesterol levels are too high, a condition called hypercholesterolemia, it increases the risk of premature atherosclerotic cardiovascular disease.

Elevated LDL levels lead to the accumulation of LDL-C in the arterial wall. Following the accumulation of LDL, its oxidation occurs. Oxidized LDL can cause extensive damage to the arterial wall, including eliciting an inflammatory response, promoting coagulation, increasing the activity of some substances that cause vasoconstriction, and inhibiting some substances that cause vasodilation.

The following are the default standard LDL cholesterol levels:

  • Optimal: less than 100 mg/ dL.
  • Near optimal/above optimal: 100 to 129 mg/dL
  • Borderline high: 130 to 159 mg/dL
  • High: 160 to 189 mg/dL
  • Very high: more than 190 mg/dL

It is known that blood lipid levels are affected by genetics, so the heritability of this trait affects the variability in the levels of parameters such as low density cholesterol (LDL), high density cholesterol (HDL), total cholesterol or triglyceride level. One of the GWAS studies carried out in recent years has studied the role of genetic mutations in lipid levels. From this study, carried out on 95.000 participants of European ancestry, 121 markers associated with this trait have been identified, with some of the most significant markers being genes such as the TOMM40 gene, which produces a protein necessary for the transport of other proteins into the mitochondria.The APOE gene, which produces apolipoproteins, essential for lipoprotein degradation and also strongly associated with Alzheimer's disease, has also been identified. Many of these identified markers have in turn been strongly associated with cardiovascular and metabolic traits, such as coronary artery disease, type 2 diabetes, blood pressure, waist-to-hip ratio and body mass index.

Number of observed variants

13.5 million variants

Number of loci analyzed in the study

121 loci

Bibliography

Willer C.J., Schmidt E.M., et al. Discovery and refinement of loci associated with lipid levels. Nature Genetics, 06 Oct 2013, 45(11):1274-1283

Nabil A.E., Meyers H.V., et al. Cholesterol: The Good, the Bad, and the Ugly – Therapeutic Targets for the Treatment of Dyslipidemia. Med Princ Pract. 2014 Feb; 23(2): 99–111.

Pirahanchi Y., Sinawe H., et al. Biochemistry, LDL Cholesterol. StatPearls

Lee Y. et Siddiqui W.J. Cholesterol Levels. StatPearls

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