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What in cigarette smoke is harmful?

Cigarette smoke is a complex mixture of chemicals produced by the burning of tobacco and its additives. The smoke contains tar, which is made up of more than 4,000 chemicals, including over 60 known to cause cancer. Some of these substances cause heart and lung diseases, and all of them can be deadly. You might be surprised to know some of the chemicals found in cigarette smoke include:

• Cyanide
• Benzene
• Formaldehyde
• Methanol (wood alcohol)
• Acetylene (the fuel used in welding torches)
• Ammonia

Cigarette smoke also contains the poison gases carbon monoxide and nitrogen oxide. The ingredient that produces the effect people are looking for is nicotine, an addictive drug.

The tobacco leaves used in making cigarettes contain radioactive materials; the amount depends on the soil the plants were grown in and fertilizers used. But this means that cigarette smoke contains small amounts of radioactive material too, which smokers take into their lungs as they inhale. These radioactive particles build up in the lungs, and over time can mean a big dose of radiation. This may be another key factor in smokers getting lung cancer.

Does smoking cause cancer?

Yes. Tobacco use accounts for at least 30% of all cancer deaths in the United States. Smoking causes about 87% of lung cancer deaths. Smoking also causes cancers of the larynx (voice box), mouth, pharynx (throat), esophagus (swallowing tube), and bladder. It also has been linked to the development of cancers of the pancreas, cervix, kidney, and stomach and some types of leukemia. Cigars, pipes, and spit and other types of smokeless tobacco all cause cancers, too. There is no safe way to use tobacco.

How does cigarette smoke affect the lungs?

Damage to the lungs begins early in smokers, and cigarette smokers have a lower level of lung function than non-smokers of the same age. Lung function continues to worsen as long as the person smokes, but it may take years for the problem to become noticeable enough for lung disease to be diagnosed. Cigarette smoking causes many lung diseases that can be nearly as bad as lung cancer.

Chronic obstructive pulmonary disease

More than 12 million people in the United States suffer from chronic obstructive pulmonary disease (COPD), a name for long-term lung disease which includes both chronic bronchitis and emphysema. COPD is the fourth leading cause of death in America. More women die from COPD than men. Smoking is the main risk factor for COPD. More than 75% of COPD deaths are caused by smoking.

Over time, COPD can make it hard to breathe, limit activity, and cause serious health problems. The late stage of chronic lung disease is one of the most miserable of all medical problems. It makes people feel as if they are gasping for breath all the time. They feel as if they are drowning.

Chronic bronchitis

Chronic bronchitis is a disease where the airways make too much mucus, forcing the smoker to cough it out. It is a common problem for smokers. The airways become inflamed (swollen) and the cough becomes chronic. It doesn't get better or go away. Airways get blocked by scars and mucus. This can lead to bad lung infections.

Emphysema

Cigarette smoking is also the major cause of emphysema, a disease that slowly destroys a person's ability to breathe. Oxygen gets into the blood by moving across a large surface area in the lungs. Normally, thousands of tiny sacs make up this surface. In emphysema, the walls between the sacs break down and create larger but fewer sacs. This decreases the lung surface area, which lowers the amount of oxygen reaching the blood. Over time, the lung surface area can become so small that a person with emphysema must gasp for breath.

Shortness of breath (especially when lying down), a mild cough that doesn't go away (which is often dismissed as "smoker's cough"), feeling tired, and sometimes weight loss are signs that emphysema is getting worse. People with emphysema are at risk for many other problems linked to weak lung function, including pneumonia. In later stages of the disease, patients can only breathe comfortably with the help of an oxygen tube under the nose. Emphysema cannot be cured or reversed, but it can be slowed down, especially if the person stops smoking.

Why do smokers have "smoker's cough?"

Cigarette smoke has chemicals and particles that irritate the airways and lungs. When a smoker inhales these substances, the body tries to protect itself by making mucus and coughing. The early morning smoker's cough happens for many reasons. Normally, tiny hair-like formations (called cilia) beat outward and sweep harmful material out of the lungs. But cigarette smoke slows the sweeping action, so some of the poisons in the smoke stay in the lungs and mucus stays in the airways. While a smoker sleeps, some cilia recover and begin working again. After waking up, the smoker coughs because the lungs are trying to clear away the irritants and mucus that built up from the day before. The cilia will completely stop working after they have been exposed to smoke for a long time. Then the smoker's lungs are even more exposed and prone to infection and irritation.

If you smoke but don't inhale, is there any danger?

Yes. Wherever smoke touches living cells, it does harm. Even if smokers don't inhale, they are breathing secondhand smoke and are still at risk for lung cancer. Pipe and cigar smokers, who often don't inhale, are at an increased risk for lip, mouth, tongue, and some other cancers, too.

Does cigarette smoking affect your heart?

Yes. Smoking cigarettes increases the risk of heart disease, which is the number one cause of death in the United States. Smoking, high blood pressure, high cholesterol, physical inactivity, obesity, and diabetes are all risk factors for heart disease. But the biggest risk factor for sudden death from a heart attack is cigarette smoking. A smoker who has a heart attack is more likely to die within an hour of the heart attack than a non-smoker. Cigarette smoke can harm the heart at very low levels, even when the amount is too low to cause lung disease.

How does smoking affect pregnant women and their babies?

Pregnant women who smoke risk the health and lives of their unborn babies, and most women try to stop smoking when they find out they're pregnant. Smoking during pregnancy is linked with a greater chance of miscarriage, premature delivery, stillbirth, infant death, low birth-weight, and sudden infant death syndrome (SIDS). Up to 5% of infant deaths could be prevented if pregnant women did not smoke.

When a pregnant woman smokes, she's smoking for 2. The nicotine, carbon monoxide, and other harmful chemicals enter her bloodstream, go into the baby's body, and keep it from getting vital nutrients and oxygen it needs for growth.

Breast-feeding is a good way to feed a new baby, but if the mother smokes the baby is exposed to nicotine and other substances in the smoke through breast milk. Nicotine can cause unwanted symptoms in the baby, such as restlessness, a rapid heartbeat, vomiting, shorter sleep times, or diarrhea. It is better not to smoke while breast feeding. But women who can't quit right away can make their homes smoke-free, smoke after breast-feeding rather than before, and cut back on their smoking as much as possible. Breast feeding may be healthier for the baby than the bottle, even when the mother smokes.

Some research has also suggested that children whose mothers smoked while pregnant or who have been exposed to secondhand smoke, even in small amounts, may be slower learners in school. They may be shorter and smaller than children of non-smokers. They are also more likely to smoke when they get older.

What are some of the short- and long-term effects of smoking cigarettes?

Smoking causes many types of cancer. But cancers account for only about half of the deaths linked to smoking. Long-term, smoking is also a major cause of heart disease, aneurysms, bronchitis, emphysema, and stroke. It also makes pneumonia and asthma worse. Smoking is linked to about half of the gum disease in the United States, which means more tooth loss and mouth surgery. Wounds take longer to heal and the immune system may not work as well in smokers as in non-smokers.

Smoking also damages the arteries. This is why many vascular surgeons refuse to operate on patients with peripheral artery disease (poor blood circulation in the arms and legs) unless they stop smoking. And male smokers have a higher risk of sexual impotence (erectile dysfunction) the longer they smoke

The truth is that cigarette smokers die younger than non-smokers. In fact, according to a study done in the late 1990s by the Centers for Disease Control and Prevention (CDC), smoking shortened male smokers' lives by 13.2 years and female smokers' lives by 14.5 years. Men and women who smoke are much more likely to die during middle age (between the ages of 35 and 69) than those who have never smoked.

Smoking also causes many short-term effects, such as poor lung function. This is why smokers often suffer shortness of breath and nagging coughs. They often will tire quickly during physical activity. Some other common short-term effects include less ability to smell and taste, premature aging of the skin, bad breath, and stained teeth

What are the chances that smoking will kill you?

About half of the people who keep smoking will die because of it. In the United States, tobacco causes nearly 1 in 5 deaths, killing about 443,000 Americans each year. Smoking is the single most preventable cause of death in our society.

Based on current patterns, smoking will kill about 650 million people alive in the world today. If these patterns continue, tobacco-caused deaths worldwide are expected to increase from about 5.4 million per year today to more than 8 million per year by the 2030s. Most of these deaths will happen in developing countries.

Last Medical Review: 01/31/2011
Last Revised: 01/31/2011