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Cigarette Smoking: Health Risks and How to Quit (PDQ®)

Patient Version
Last Modified: 02/24/2012

General Information About Tobacco Use

Key Points for This Section


Smoking is the leading cause of cancer in the United States.

Smoking increases the risk of many types of cancer. These include:

A smoker’s risk of cancer can be 2 to 10 times higher than it is for a person who never smoked. This depends on how much and how long the person smoked.

In 2007, about 22% of adult men and about 17% of adult women were smokers. Lung cancer is the leading cause of cancer death in both men and women. In the last 30 years, the total number of smokers has decreased, especially among men. Since the 1980s, deaths caused by lung cancer in men have been decreasing.

Smoking causes many other health problems.

Smoking is linked with many diseases besides cancer. These include:

Other health problems that may be linked to smoking are:

Smoking during pregnancy may cause problems such as slow growth of the fetus and low birth weight.

Being exposed to secondhand smoke increases the risk of cancer and other diseases.

Smoking can also affect the health of nonsmokers. Smoke that comes from the burning of a tobacco product or smoke that is exhaled by smokers is called secondhand smoke. Inhaling secondhand smoke is called involuntary or passive smoking.

The same cancer-causing chemicals inhaled by tobacco smokers are inhaled in lower amounts by people exposed to secondhand tobacco smoke. Nonsmokers who are exposed to secondhand smoke have a higher risk of lung cancer and coronary heart disease. Children exposed to tobacco smoke have higher risks of the following:



Glossary Terms

acute myeloid leukemia (uh-KYOOT MY-eh-loyd loo-KEE-mee-uh)
An aggressive (fast-growing) disease in which too many myeloblasts (immature white blood cells that are not lymphoblasts) are found in the bone marrow and blood. Also called acute myeloblastic leukemia, acute myelogenous leukemia, acute nonlymphocytic leukemia, AML, and ANLL.
asthma (AZ-muh)
A chronic disease in which the bronchial airways in the lungs become narrowed and swollen, making it difficult to breathe. Symptoms include wheezing, coughing, tightness in the chest, shortness of breath, and rapid breathing. An attack may be brought on by pet hair, dust, smoke, pollen, mold, exercise, cold air, or stress.
bladder cancer (BLA-der KAN-ser)
Cancer that forms in tissues of the bladder (the organ that stores urine). Most bladder cancers are transitional cell carcinomas (cancer that begins in cells that normally make up the inner lining of the bladder). Other types include squamous cell carcinoma (cancer that begins in thin, flat cells) and adenocarcinoma (cancer that begins in cells that make and release mucus and other fluids). The cells that form squamous cell carcinoma and adenocarcinoma develop in the inner lining of the bladder as a result of chronic irritation and inflammation.
bronchitis (bron-KY-tis)
Inflammation (swelling and reddening) of the bronchi.
cancer (KAN-ser)
A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is a cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord. Also called malignancy.
cataract (KA-tuh-RAKT)
A condition in which the lens of the eye becomes cloudy. Symptoms include blurred, cloudy, or double vision; sensitivity to light; and difficulty seeing at night. Without treatment, cataracts can cause blindness. There are many different types and causes of cataracts. They may occur in people of all ages, but are most common in the elderly.
cavity (KA-vih-tee)
A hollow area or hole. It may describe a body cavity (such as the space within the abdomen) or a hole in a tooth caused by decay.
cervical cancer (SER-vih-kul KAN-ser)
Cancer that forms in tissues of the cervix (the organ connecting the uterus and vagina). It is usually a slow-growing cancer that may not have symptoms but can be found with regular Pap tests (a procedure in which cells are scraped from the cervix and looked at under a microscope). Cervical cancer is almost always caused by human papillomavirus (HPV) infection.
chemical (KEH-mih-kul)
A substance made up of elements, such as hydrogen or sodium.
coronary heart disease (KOR-uh-NAYR-ee hart dih-ZEEZ)
A disease in which there is a narrowing or blockage of the coronary arteries (blood vessels that carry blood and oxygen to the heart). Coronary heart disease is usually caused by atherosclerosis (a build up of fatty material and plaque inside the coronary arteries). The disease may cause chest pain, shortness of breath during exercise, and heart attacks. The risk of coronary heart disease is increased by having a family history of coronary heart disease before age 50, older age, smoking tobacco, high blood pressure, high cholesterol, diabetes, lack of exercise, and obesity. Also called CAD and coronary artery disease.
emphysema (EMP-fuh-ZEE-muh)
Pulmonary emphysema is a disorder affecting the alveoli (tiny air sacs) of the lungs. The transfer of oxygen and carbon dioxide in the lungs takes place in the walls of the alveoli. In emphysema, the alveoli become abnormally inflated, damaging their walls and making it harder to breathe. People who smoke or have chronic bronchitis have an increased risk of emphysema.
esophageal cancer (ee-SAH-fuh-JEE-ul KAN-ser)
Cancer that forms in tissues lining the esophagus (the muscular tube through which food passes from the throat to the stomach). Two types of esophageal cancer are squamous cell carcinoma (cancer that begins in flat cells lining the esophagus) and adenocarcinoma (cancer that begins in cells that make and release mucus and other fluids).
fetus (FEE-tus)
In humans, an unborn baby that develops and grows inside the uterus (womb). The fetal period begins 8 weeks after fertilization of an egg by a sperm and ends at the time of birth.
infection (in-FEK-shun)
Invasion and multiplication of germs in the body. Infections can occur in any part of the body and can spread throughout the body. The germs may be bacteria, viruses, yeast, or fungi. They can cause a fever and other problems, depending on where the infection occurs. When the body’s natural defense system is strong, it can often fight the germs and prevent infection. Some cancer treatments can weaken the natural defense system.
inhalation (IN-huh-LAY-shun)
In medicine, refers to the act of taking a substance into the body by breathing.
involuntary (in-VAH-lun-TAYR-ee)
An action that is not made by choice. In the body, involuntary actions (such as blushing) occur automatically, and cannot be controlled by choice.
kidney cancer (KID-nee KAN-ser)
Cancer that forms in tissues of the kidneys. Kidney cancer includes renal cell carcinoma (cancer that forms in the lining of very small tubes in the kidney that filter the blood and remove waste products) and renal pelvis carcinoma (cancer that forms in the center of the kidney where urine collects). It also includes Wilms tumor, which is a type of kidney cancer that usually develops in children under the age of 5.
lung cancer (lung KAN-ser)
Cancer that forms in tissues of the lung, usually in the cells lining air passages. The two main types are small cell lung cancer and non-small cell lung cancer. These types are diagnosed based on how the cells look under a microscope.
nasal (NAY-zul)
By or having to do with the nose.
oral cancer (OR-ul KAN-ser)
Cancer that forms in tissues of the oral cavity (the mouth) or the oropharynx (the part of the throat at the back of the mouth).
pancreatic cancer (PAN-kree-A-tik KAN-ser)
A disease in which malignant (cancer) cells are found in the tissues of the pancreas. Also called exocrine cancer.
pregnancy (PREG-nun-see)
The condition between conception (fertilization of an egg by a sperm) and birth, during which the fertilized egg develops in the uterus. In humans, pregnancy lasts about 288 days.
respiratory tract (RES-pih-ruh-TOR-ee trakt)
The organs that are involved in breathing. These include the nose, throat, larynx, trachea, bronchi, and lungs. Also called respiratory system.
secondhand smoke (SEH-kund-hand ...)
Smoke that comes from the burning of a tobacco product and smoke that is exhaled by smokers. Inhaling secondhand smoke is called involuntary or passive smoking. Also called environmental tobacco smoke and ETS.
stomach cancer (STUH-muk KAN-ser)
Cancer that forms in tissues lining the stomach. Also called gastric cancer.
stroke (stroke)
In medicine, a loss of blood flow to part of the brain, which damages brain tissue. Strokes are caused by blood clots and broken blood vessels in the brain. Symptoms include dizziness, numbness, weakness on one side of the body, and problems with talking, writing, or understanding language. The risk of stroke is increased by high blood pressure, older age, smoking, diabetes, high cholesterol, heart disease, atherosclerosis (a build-up of fatty material and plaque inside the coronary arteries), and a family history of stroke.
sudden infant death syndrome (suh-DEN in-FUNT deth SIN-drome)
The sudden and unexpected death of a healthy child who is younger than one year old, usually during sleep. The cause of sudden infant death syndrome is not known. Also called crib death and SIDS.
throat cancer (throte KAN-ser)
Cancer that forms in tissues of the pharynx (the hollow tube inside the neck that starts behind the nose and ends at the top of the windpipe and esophagus). Throat cancer includes cancer of the nasopharynx (the upper part of the throat behind the nose), the oropharynx (the middle part of the pharynx), and the hypopharynx (the bottom part of the pharynx). Cancer of the larynx (voice box) may also be included as a type of throat cancer. Most throat cancers are squamous cell carcinomas (cancer that begins in thin, flat cells that look like fish scales). Also called pharyngeal cancer.
tobacco (tuh-BA-koh)
A plant with leaves that have high levels of the addictive chemical nicotine. The leaves may be smoked (in cigarettes, cigars, and pipes), applied to the gums (as dipping and chewing tobacco), or inhaled (as snuff). Tobacco leaves also contain many cancer-causing chemicals, and tobacco use and exposure to secondhand tobacco smoke have been linked to many types of cancer and other diseases. The scientific name is Nicotiana tabacum.