The main cause of cardiovascular disease is atherosclerosis, the gradual buildup of fatty deposits inside artery walls that restricts blood flow and can trigger heart attacks and strokes. An estimated 19.8 million people died from cardiovascular disease in 2022, roughly 32% of all deaths worldwide, and atherosclerosis is the underlying process behind the vast majority of those deaths. While no single factor works alone, a handful of well-understood risk factors drive this process, and most of them are within your control.
How Atherosclerosis Develops
Atherosclerosis doesn’t happen overnight. It begins when LDL cholesterol particles, commonly called “bad” cholesterol, seep into the inner lining of an artery and get trapped there. Once lodged in the artery wall, these particles undergo chemical changes: they oxidize and clump together. The damaged particles then irritate the surrounding cells, which send out distress signals in the form of sticky molecules and chemical attractants.
White blood cells respond to these signals by migrating into the artery wall, where they transform into specialized immune cells that try to swallow up the modified cholesterol. But instead of solving the problem, these cells become engorged with fat and form what pathologists call “foam cells,” the earliest visible sign of a plaque. Over years and decades, layers of these fat-laden immune cells, calcium, and fibrous tissue accumulate into a raised bump that narrows the artery. If the surface of that plaque cracks open, a blood clot can form on the spot, suddenly blocking the artery and causing a heart attack or stroke.
This entire process is fueled and accelerated by several interconnected risk factors. Rarely does one cause act in isolation. Instead, high blood pressure, high cholesterol, smoking, diabetes, obesity, and genetics compound each other’s effects.
High Blood Pressure
Elevated blood pressure is one of the most powerful drivers of cardiovascular disease. The risk of heart attack, stroke, and heart failure climbs steadily once blood pressure exceeds roughly 115/75 mmHg, a level well below the traditional “high blood pressure” cutoff. For every 20-point increase in the upper number (systolic) or 10-point increase in the lower number (diastolic), your risk of cardiovascular disease roughly doubles.
The damage is mechanical. When blood pushes against artery walls with too much force, it injures the delicate inner lining, making it easier for cholesterol to penetrate and plaque to form. Over time, the heart also has to work harder to pump against that resistance, causing the muscle to thicken and eventually weaken. This is why high blood pressure is the single largest contributor to heart failure in many populations, even when cholesterol levels are normal.
High Cholesterol and Genetic Risk
Because LDL cholesterol is the raw material that builds arterial plaques, anything that raises its levels or keeps it circulating longer accelerates the disease. Diet plays a role, but genetics can matter just as much. Some people inherit a tendency to produce more LDL or clear it from the bloodstream more slowly, giving cholesterol more time to infiltrate artery walls.
One genetic factor that has drawn increasing attention is a particle called lipoprotein(a), or Lp(a). Unlike regular LDL, Lp(a) levels are almost entirely determined by your genes. Each doubling of Lp(a) in the bloodstream is associated with a 22% greater risk of heart attack, independent of other risk factors. The risk rises in a graded fashion: for every standardized increment in Lp(a), heart disease risk climbs about 11%, and this holds true across all racial and ethnic groups studied. Most routine cholesterol panels don’t measure Lp(a), so many people with elevated levels never find out.
Smoking
Tobacco smoke damages arteries through multiple pathways at once. It injures the inner lining of blood vessels, makes blood more likely to clot, raises LDL cholesterol, and lowers HDL (“good”) cholesterol. The combined effect substantially accelerates plaque formation.
The good news is that the damage is partially reversible. After one year of quitting, the excess cardiovascular risk from smoking drops by half. After 15 years of abstinence, the risk of coronary heart disease returns to that of someone who never smoked. Few lifestyle changes offer that kind of measurable payoff on a defined timeline.
Diabetes and Blood Sugar
Persistently high blood sugar damages blood vessels from the inside. Over time, excess glucose in the bloodstream attaches to proteins in the artery walls through a process that stiffens them, reducing their ability to flex with each heartbeat. This stiffening affects both large arteries and the tiny vessels that supply blood to the heart muscle itself. The result is impaired blood flow and a heart that has to work harder against increasingly rigid plumbing.
Diabetes also pushes the body toward a pro-clotting state, meaning that when a plaque does rupture, the resulting clot is more likely to be large enough to block an artery completely. This is why people with diabetes face two to four times the cardiovascular risk of people without it, even when other risk factors are managed.
Obesity and Belly Fat
Not all body fat carries the same risk. Fat stored deep in the abdomen, around the organs (visceral fat), is far more dangerous than fat under the skin. Visceral fat acts almost like an endocrine organ, actively pumping out inflammatory signals that travel throughout the body. Research shows that visceral fat tissue secretes far greater amounts of key inflammatory molecules compared to subcutaneous fat stored on the hips or thighs.
These inflammatory signals damage artery linings, promote clot formation, and make existing plaques less stable and more prone to rupture. This chronic low-grade inflammation is one reason why people carrying excess weight around the midsection face higher cardiovascular risk, even if their cholesterol and blood pressure numbers look reasonable. Losing visceral fat, even modest amounts, reduces these inflammatory signals and measurably lowers risk.
The Role of Chronic Inflammation
Inflammation ties many of these risk factors together. High blood pressure injures arteries and triggers an inflammatory response. Visceral fat secretes inflammatory chemicals. Diabetes promotes vascular inflammation. Smoking does the same. Even cholesterol buildup in artery walls is fundamentally an inflammatory process, driven by immune cells trying to clean up the damage.
Doctors can measure this systemic inflammation with a blood test called high-sensitivity CRP. Levels below 1 mg/L are considered low risk, 1 to 3 mg/L indicate intermediate risk, and readings above 3 mg/L signal high cardiovascular risk. This marker helps explain why some people with “normal” cholesterol still develop heart disease: their arteries are inflamed by other forces.
What You Can Do About It
Because atherosclerosis develops over decades, the window for prevention is wide. The most effective steps target the risk factors above simultaneously. Current guidelines recommend at least 150 minutes per week of moderate-intensity exercise (like brisk walking) or 75 minutes of vigorous exercise (like jogging), plus two or more days of strength training. Regular physical activity lowers blood pressure, improves cholesterol ratios, reduces visceral fat, and dampens chronic inflammation all at once.
A dietary pattern rich in vegetables, fruits, whole grains, and unsaturated fats while low in processed foods, added sugars, and excess sodium addresses several risk factors in parallel. If you smoke, quitting delivers one of the fastest and most dramatic risk reductions available. And if you have high blood pressure or diabetes, keeping those conditions well managed slows the atherosclerotic process significantly.
The core takeaway is that cardiovascular disease is not the result of one broken system. It’s the product of several forces, most of them modifiable, converging on the same vulnerable target: your artery walls. The earlier and more consistently you address those forces, the less opportunity atherosclerosis has to progress.