Cholesterol, a waxy, fat-like substance naturally produced in the liver and found in certain foods, is essential to numerous biological functions. It helps build cell membranes, produce hormones, and facilitate the production of vitamin D. Despite its necessity, cholesterol can become a silent and deadly threat when present in excessive amounts in the bloodstream. High cholesterol is one of the most significant risk factors for various cardiovascular diseases, including heart attacks, strokes, and peripheral artery disease. It is a condition that has no direct symptoms but can lead to severe and often fatal health outcomes if left unchecked.
What is cholesterol and why it matters?
Cholesterol is transported through the bloodstream by lipoproteins, which are classified mainly into three types:
- Low-Density Lipoprotein (LDL) “Bad” Cholesterol: LDL is considered “bad” because it transports cholesterol from the liver to the cells. Excessive LDL in the bloodstream can lead to cholesterol deposition in the artery walls, forming plaques that narrow and harden the arteries, a process known as atherosclerosis.
- High-Density Lipoprotein (HDL) “Good” Cholesterol: HDL is termed “good” because it collects excess cholesterol from the bloodstream and transports it back to the liver for excretion or reprocessing. High levels of HDL are associated with a lower risk of heart disease.
- Triglycerides: Triglycerides are a type of fat found in the blood. Though not technically cholesterol, their levels are measured in a standard lipid panel because high triglycerides can also contribute to plaque formation and cardiovascular disease.
How deadly is high cholesterol?
Cholesterol becomes dangerous when its levels, particularly LDL, rise beyond what the body needs. Here’s how elevated cholesterol contributes to mortality:
1. Plaque Formation and Atherosclerosis
When there is too much LDL cholesterol in the blood, it begins to accumulate on the walls of arteries. These deposits, known as plaques, cause the arterial walls to become thick and stiff a condition called atherosclerosis. Over time, plaques can rupture, triggering the formation of blood clots that may block blood flow entirely.
2. Narrowed Arteries and Reduced Blood Flow
As plaques grow, they restrict blood flow to critical organs like the heart and brain. Restricted blood flow can result in ischemia, or oxygen starvation, leading to tissue damage or death.
3. Clot Formation
Plaque ruptures create sites where blood clots can form. If a clot completely blocks a coronary artery, it can cause a heart attack. If it blocks a cerebral artery, it leads to a stroke. Both conditions can cause sudden death or irreversible organ damage.
Major Diseases Caused by High Cholesterol That Increase Mortality
High cholesterol is not a disease in itself but a major risk factor that leads to several deadly conditions. The following are some of the most significant health issues caused by high cholesterol:
1. Coronary Artery Disease (CAD)
CAD is one of the most common outcomes of high cholesterol. As arteries that supply blood to the heart become narrowed or blocked, the risk of heart attack increases. According to the CDC, CAD is the leading cause of death in the United States. Heart attacks caused by complete artery blockage can be fatal, especially if medical help is not immediately available.
2. Stroke
A stroke occurs when the blood supply to a part of the brain is interrupted or reduced. High cholesterol leads to plaque buildup in the arteries supplying the brain, increasing the risk of both ischemic and hemorrhagic strokes. The former is caused by a blockage, while the latter is caused by a ruptured blood vessel.
3. Peripheral Artery Disease (PAD)
PAD occurs when cholesterol plaques accumulate in arteries that supply blood to the limbs, usually the legs. While not immediately fatal, PAD is associated with a higher risk of heart attacks and strokes and can lead to gangrene and limb amputation.
4. High Blood Pressure (Hypertension)
Atherosclerosis caused by high cholesterol increases the resistance in blood vessels, forcing the heart to pump harder. Over time, this leads to high blood pressure, which itself is a risk factor for heart failure, kidney disease, and stroke.
5. Type 2 Diabetes Complications
People with diabetes often have lipid imbalances, including high LDL and triglycerides and low HDL. This lipid profile significantly raises their risk of cardiovascular complications and mortality. The combination of high cholesterol and diabetes is particularly lethal.
6. Obesity and Metabolic Syndrome
Obesity often accompanies high cholesterol and is itself a risk factor for numerous deadly diseases. It contributes to high blood pressure, insulin resistance, and inflammation all of which can worsen the impact of high cholesterol.
