How Does Smoking Cause Atherosclerosis?

The Link Between Smoking and Atherosclerosis

Updated on August 29, 2021

Medically reviewed by

Atherosclerosis is a life-threatening disease in which cholesterol, cellular waste, calcium, and other fatty substances are deposited along the lining of artery walls in your body. These sticky, yellowish deposits, known as plaque, build up over time, hindering your blood flow. If you smoke, you face an increased risk of atherosclerosis, heart attack, and stroke.

What Is Atherosclerosis?

Atherosclerosis, also known as hardening of the arteries or arteriosclerosis, often starts early in life and progresses slowly as you age. Atherosclerosis typically affects medium and large arteries in the body. Many scientists believe that damage to the endothelium, the innermost layer of the artery, is where atherosclerosis begins.

Damage to the endothelium allows plaque to build up along the lining of your arterial walls. As it does, it constricts blood flow and decreases the supply of oxygen to your body.

Effects of Atherosclerosis

Plaque can rupture and cause blood clots (thrombus). These blood clots can break away and enter your bloodstream, lodging in another part of your body, sometimes completely blocking blood flow, called an embolus.

Fatty embolisms that block blood flow to your heart cause a heart attack. If they block blood flow to your brain, they cause a stroke. If blood flow to your arms and legs is reduced, it can cause you to have difficulty walking and eventually lead to gangrene, which is when tissue dies due to lack of blood supply.

Causes and Risk Factors

Though the precise cause of atherosclerosis is unknown, there are some known risk factors. Because high cholesterol and high blood pressure can cause damage to the innermost layer of the artery where atherosclerosis begins, they are considered two of the potential causes of the condition.

Elevated Cholesterol and Triglyceride Levels

Elevated levels of cholesterol and triglycerides in your blood cause damage to your endothelium. The body needs cholesterol (mainly high-density lipoprotein or HDL), but too much comes with health risks. Your body usually produces most of the cholesterol it needs in your liver. The rest comes from animal fat in your diet.

While our bodies also need some low-density lipoprotein (LDL) cholesterol, too much can raise your cholesterol levels dangerously and put you at risk for atherosclerosis and heart attack. Foods that come from animals, such as chicken, eggs, dairy products, beef, and pork, contain cholesterol. Foods from plants do not contain cholesterol.

High Blood Pressure

Blood pressure is the result of two forces. One is the pressure created by your heart pumping blood through your circulatory system. The other is the force of the resistance of the arteries as your blood flows through them.

When your heart pumps, it pushes blood through the larger arteries and on into the smaller blood vessels, called arterioles. The arterioles can constrict or expand, and when they do, the resistance of the blood flow is affected.

The more difficult it is for the blood to flow, the higher your blood pressure will be.

When high blood pressure goes untreated for a long time and your heart is forced to pump harder to get the blood to flow, your heart muscle may become enlarged and weakened. High blood pressure hurts your arteries and arterioles over time as well. Arteries become scarred and hardened, putting you at risk for atherosclerosis.

How Smoking Affects Atherosclerosis Risk

Smoking is considered one of the biggest risk factors for atherosclerosis. Cigarette smoke increases the risk of atherosclerosis in the following ways:

Cholesterol: The toxins in tobacco smoke lower your HDL ("good" cholesterol) levels while raising levels of LDL ("bad" cholesterol).
Nicotine and carbon monoxide: The nicotine and carbon monoxide in cigarette smoke damage your endothelium, setting the stage for the build-up of plaque.
High blood pressure: While cigarette smoking won't cause high blood pressure, if you smoke and you also have hypertension, smoking can increase the risk of malignant hypertension, a dangerous form of high blood pressure.

It's Never Too Late to Quit

If you smoke and you're thinking about quitting, know that it's never too late to quit. Regardless of your age or how many years you've smoked, research has shown that your body will begin the healing process within 20 minutes of your last cigarette.

Within one year of quitting smoking, your risk for coronary artery disease drops to half that of someone who smokes.

Between 5 and 15 years of quitting, your risk of coronary disease and stroke drops to that of nonsmokers.

Trying to quit smoking isn't easy, but it's worth it. The encouraging news is that according to statistics from the Centers for Disease Control and Prevention (CDC), more than three out of every five people who have ever smoked cigarettes in the United States have quit. You can, too.

There are many strategies that may help manage the stress associated with quitting and help you deal with cravings, such as:

Getting some exercise
Doing deep breathing exercises
Reaching out to your support system
Speaking with a counselor or joining a support group

Healthy coping mechanisms for dealing with stress are also good for heart health, so it's a win-win.

There are also medications that can help you quit. Consult with your healthcare provider about your desire to quit. They can help you find what works best for you.