What are the risks of tobacco smoke to nonsmokers?


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Secondhand smoke (also called environmental tobacco smoke, involuntary smoking, and passive smoking) is the combination of “sidestream” smoke (the smoke given off by a burning tobacco product) and “mainstream” smoke (the smoke exhaled by a smoker) (4, 5, 8, 9). The U.S. Environmental Protection Agency, the U.S. National Toxicology Program, the U.S. Surgeon General, and the International Agency for Research on Cancer have classified secondhand smoke as a known human carcinogen (cancer-causing agent) (5, 9, 10). Inhaling secondhand smoke causes lung cancer in nonsmoking adults (1, 2, 4). Approximately 7,300 lung cancer deaths occur each year among adult nonsmokers in the United States as a result of exposure to secondhand smoke (1). The U.S. Surgeon General estimates that living with a smoker increases a nonsmoker’s chances of developing lung cancer by 20 to 30 percent (4).

Secondhand smoke causes disease and premature death in nonsmoking adults and children (2, 4). Exposure to secondhand smoke may increase the risk of heart disease by an estimated 25 to 30 percent (4). In the United States, exposure to secondhand smoke is thought to cause about 34,000 deaths from heart disease each year (1). Exposure to secondhand smoke also increases the risk of stroke by 20 to 30 percent (1). Pregnant women exposed to secondhand smoke are at risk of having a baby with low birth weight (2). Children exposed to secondhand smoke are at an increased risk of SIDS, ear infections, colds, pneumonia, and bronchitis.  It can also increase the frequency and severity of asthma symptoms among children who have asthma. Being exposed to secondhand smoke slows the growth of children’s lungs and can cause them to cough, wheeze, and feel breathless (2, 4).

Is smoking addictive?

Yes. Nicotine is a drug that is naturally present in the tobacco plant and is primarily responsible for a person’s addiction to tobacco products, including cigarettes. The addiction to cigarettes and other tobacco products that nicotine causes is similar to the addiction produced by using drugs such as heroin and cocaine (11).

How much nicotine is in cigarettes and cigars?

Cigarettes, cigars, and other tobacco products vary widely in their content of nicotine, cancer-causing substances, and other toxicants. In a cigarette (which contains 0.49 to 0.89 gram of tobacco), the nicotine content can vary between 13.79 and 22.68 milligrams per gram of dry tobacco (12, 13). In a cigar (which can contain as many as 21.5 grams of tobacco), the nicotine content can vary between 6.3 and 15.6 milligrams per gram of tobacco or 5.9 to 335.2 milligrams per cigar (14).

The way a person smokes a tobacco product is as important as the nicotine content of the product in determining how much nicotine gets into the body. Nicotine is absorbed into the bloodstream through the lining of the mouth and the lungs and travels to the brain in a matter of seconds. Taking more frequent and deeper puffs of tobacco smoke increases the amount of nicotine absorbed by the body.

Are other tobacco products, such as smokeless tobacco or pipe tobacco, harmful and addictive?

Yes. All forms of tobacco are harmful and addictive (4, 9). There is no safe tobacco product.

In addition to cigarettes and cigars, other forms of tobacco include smokeless tobacco (also called chewing tobacco, snuff, and snus), pipes, hookahs (waterpipes), bidis, and kreteks. 

• Pipes: Pipe smoking causes lung cancer and increases the risk of cancers of the mouth, throat, larynx, and esophagus (9, 15, 16).

• Hookahs or waterpipes (other names include argileh, ghelyoon, hubble bubble, shisha, boory, goza, and narghile): A hookah is a device used to smoke tobacco. The smoke passes through a partially filled water bowl before being inhaled by the smoker. Some people think hookah smoking is less harmful and addictive than smoking cigarettes (17), but research suggests that waterpipe smoke is at least as toxic as cigarette smoke (18, 19).

• Bidis: A bidi is a flavored cigarette made by rolling tobacco in a dried leaf from the tendu tree, which is native to India. Bidi use is associated with heart attacks and cancers of the mouth, throat, larynx, esophagus, and lung (9, 20).

• Kreteks: A kretek is a cigarette made with a mixture of tobacco and cloves. Smoking kreteks is associated with lung cancer and other lung diseases (9, 20).