Provided by National Cancer Institute
Health problems caused by smoking
Smoking harms nearly every organ of the body and diminishes a person's overall health. Smoking is a leading cause of cancer and of death from cancer. It causes cancers of the lung, esophagus, larynx (voice box), mouth, throat, kidney, bladder, pancreas, stomach and cervix, as well as acute myeloid leukemia.1Smokers are at higher risk of developing pneumonia and other airway infections.
Cigarette smoking and exposure to tobacco smoke cause an estimated average of 438,000 premature deaths each year in the U.S. Of these, about 40 percent are from cancer, 35 percent are from heart disease and stroke, and 25 percent are from lung disease. Smoking is the leading cause of premature, preventable death in this country.
Tobacco smoke contains chemicals that are harmful to both smokers and nonsmokers. Breathing even a little tobacco smoke can be harmful. Of the 4,000 chemicals in tobacco smoke, at least 250 are known to be harmful.
Of the 250 known harmful chemicals in tobacco smoke, more than 50 have been found to cause cancer. These chemicals include:
- Arsenic (a heavy metal toxin)
- Benzene (a chemical found in gasoline)
- Beryllium (a toxic metal)
- Cadmium (a metal used in batteries)
- Chromium (a metallic element)
- Ethylene oxide (a chemical used to sterilize medical devices)
- Nickel (a metallic element)
- Polonium-210 (a chemical element that gives off radiation)
- Vinyl chloride (a toxic substance used in plastics manufacture)
The immediate benefits of quitting
When you quit smoking, your heart rate and blood pressure, which were abnormally high while smoking, begin to return to normal. Within a few hours, the level of carbon monoxide in the blood begins to decline. Within a few weeks, people who quit smoking have improved circulation, don't produce as much phlegm and don't cough or wheeze as often. Within several months of quitting, people can expect significant improvements in lung function.
People who quit smoking, regardless of their age, are less likely than those who continue to smoke to die from smoking-related illness. Studies have shown that quitting at about age 30 reduces the chance of dying from smoking-related diseases by more than 90 percent. People who quit at about age 50 reduce their risk of dying prematurely by 50 percent, compared with those who continue to smoke.8 Even people who quit at about age 60 or older live longer than those who continue to smoke.
Lower the risk of cancer
Quitting smoking substantially reduces the risk of developing and dying from cancer, and this benefit increases the longer a person remains smoke-free. However, even after many years of not smoking, the risk of lung cancer in former smokers remains higher than in people who have never smoked.
The risk of premature death and the chance of developing cancer due to cigarettes depend on the number of years of smoking, the number of cigarettes smoked per day, the age at which smoking began, and the presence or absence of illness at the time of quitting. For people who have already developed cancer, quitting smoking reduces the risk of developing a second cancer.
Quitting may cause short-term problems, especially for those who have smoked a large number of cigarettes for a long period of time:
- Feeling sad or anxious: People who quit are likely to have symptoms of nicotine withdrawal, such as feeling depressed, irritable and restless, and having difficulty sleeping or concentrating.
- Gaining weight: Increased appetite is a common withdrawal symptom after quitting smoking, and studies show that people who quit smoking increase their food intake. Although most smokers gain less than 10 pounds, for some people the weight gain can be troublesome. Regular physical activity can help people maintain a healthy weight.
Many people find that nicotine replacement products and other medicines may relieve these problems associated with nicotine withdrawal. However, even without medication, withdrawal symptoms and other problems do subside over time. It helps to keep in mind that people who kick the smoking habit have the opportunity for a healthier future.
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