Smokeless Tobacco and Cancer
Key Points
· Smokeless tobacco is tobacco that is not burned. Smokeless tobacco is also known as chewing tobacco, oral tobacco, spit or spitting tobacco, dip, chew, and snuff/snus.
· Smokeless tobacco causes cancer and other diseases.
· Smokeless tobacco is not a safe substitute for cigarettes.
1. What is smokeless tobacco?
Smokeless tobacco is tobacco that is not burned. It is also known as chewing tobacco, oral tobacco, spit or spitting tobacco, dip, chew, and snuff. Most people chew or suck (dip) the tobacco in their mouth and spit out the tobacco juices that build up, although “spitless” smokeless tobacco has also been developed. Nicotine in the tobacco is absorbed through the lining of the mouth.
People in many regions and countries, including North America, northern Europe, India and other Asian countries, and parts of Africa, have a long history of using smokeless tobacco products.
There are two main types of smokeless tobacco:
· Chewing tobacco, which is available as loose leaves, plugs (bricks), or twists of rope. A piece of tobacco is placed between the cheek and lower lip, typically toward the back of the mouth. It is either chewed or held in place. Saliva is spit or swallowed.
· Snuff, which is finely cut or powdered tobacco. It may be sold in different scents and flavors. It is packaged moist or dry; most American snuff is moist. It is available loose, in dissolvable lozenges or strips, or in small pouches similar to tea bags. The user places a pinch or pouch of moist snuff between the cheek and gums or behind the upper or lower lip. Another name for moist snuff is snus (pronounced “snoose”). Some people inhale dry snuff into the nose.
2. Are there harmful chemicals in smokeless tobacco?
Yes. There is no safe form of tobacco. At least 28 chemicals in smokeless tobacco have been found to cause cancer. The most harmful chemicals in smokeless tobacco are tobacco-specific nitrosamines, which are formed during the growing, curing, fermenting, and aging of tobacco. The level of tobacco-specific nitrosamines varies by product. Scientists have found that the nitrosamine level is directly related to the risk of cancer.
In addition to a variety of nitrosamines, other cancer-causing substances in smokeless tobacco include polonium–210 (a radioactive element found in tobacco fertilizer) and polynuclear aromatic hydrocarbons (also known as polycyclic aromatic hydrocarbons).
3. Does smokeless tobacco cause cancer?
Yes. Smokeless tobacco causes oral cancer, esophageal cancer, and pancreatic cancer.
4. Does smokeless tobacco cause other diseases?
Yes. Using smokeless tobacco may also cause heart disease, gum disease, and oral lesions other than cancer, such as leukoplakia (precancerous white patches in the mouth).
5. Can a user get addicted to smokeless tobacco?
Yes. All tobacco products, including smokeless tobacco, contain nicotine, which is addictive. Users of smokeless tobacco and users of cigarettes have comparable levels of nicotine in the blood. In users of smokeless tobacco, nicotine is absorbed through the mouth tissues directly into the blood, where it goes to the brain. Even after the tobacco is removed from the mouth, nicotine continues to be absorbed into the bloodstream. Also, the nicotine stays in the blood longer for users of smokeless tobacco than for smokers.
The level of nicotine in the blood depends on the amount of nicotine in the smokeless tobacco product, the tobacco cut size, the product’s pH (a measure of its acidity or basicity), and other factors.
A Centers for Disease Control and Prevention study of the 40 most widely used popular brands of moist snuff showed that the amount of nicotine per gram of tobacco ranged from 4.4 milligrams to 25.0 milligrams. Other studies have shown that moist snuff had between 4.7 and 24.3 milligrams per gram of tobacco, dry snuff had between 10.5 and 24.8 milligrams per gram of tobacco, and chewing tobacco had between 3.4 and 39.7 milligrams per gram of tobacco.
6. Is using smokeless tobacco less hazardous than smoking cigarettes?
Because all tobacco products are harmful and cause cancer, the use of all of these products should be strongly discouraged. There is no safe level of tobacco use. People who use any type of tobacco product should be urged to quit.
As long ago as 1986, the advisory committee to the Surgeon General concluded that the use of smokeless tobacco “is not a safe substitute for smoking cigarettes. It can cause cancer and a number of noncancerous oral conditions and can lead to nicotine addiction and dependence”. Furthermore, a panel of experts convened by the National Institutes of Health (NIH) in 2006 stated that the “range of risks, including nicotine addiction, from smokeless tobacco products may vary extensively because of differing levels of nicotine, carcinogens, and other toxins in different products”.
7. Should smokeless tobacco be used to help a person quit smoking?
No. There is no scientific evidence that using smokeless tobacco can help a person quit smoking. Because all tobacco products are harmful and cause cancer, the use of all tobacco products is strongly discouraged. There is no safe level of tobacco use. People who use any type of tobacco product should be urged to quit. For help with quitting, ask your doctor about individual or group counseling, telephone quitlines, or other methods.
Smokeless Tobacco and Cancer
‘Smokeless tobacco’ is a very broad term that refers to over 30 different types of products. Smokeless tobacco products include chewed tobacco (‘dry chewing tobacco’) and sucked tobacco (‘moist oral tobacco’), rather than smoked tobacco in the form of cigarettes. There are some inhaled tobacco products (‘nasal snuff’), but these are less common in the UK.
Some people believe that smokeless tobacco is a harmless alternative to smoking cigarettes. But scientists have shown that many forms of smokeless tobacco increase your risk of mouth cancer and oesophageal (food pipe) cancer. They could also increase your risk of pancreatic cancer, liver cancer, and other conditions including gum disease and heart disease.
Different types of smokeless tobacco
Almost all types of smokeless tobacco can cause mouth cancer. But some types or brands can be more dangerous than others. This is because different products can have very different levels of cancer-causing chemicals.
Most smokeless tobacco products in the UK are used by South Asian communities. In these communities, dry chewing tobacco is often used as part of a ‘betel quid’ or ‘paan’. These consist of a mixture of betel nut (or areca nut), slaked lime and various herbs and spices, wrapped in a betel leaf.
Betel nut itself can cause cancer, so chewing betel quids can cause mouth cancer even if no tobacco is added.
What’s in smokeless tobacco?
Most types of smokeless tobacco contains at least 28 different chemicals that can cause cancer.
The worst of these are a group of chemicals called tobacco-specific nitrosamines, or TSNAs for short. Some smokeless tobacco brands can contain up to 100 times more TSNAs than any other product including cigarettes. People who use these brands can expose themselves to up to a thousand times more TSNAs than non-smokers.
As addictive as smoking
Smokeless tobacco contains as much, if not more, nicotine than smoked tobacco products do. So like cigarettes, it is highly addictive.
People who use smokeless tobacco absorb 3-4 times as much nicotine as smokers do. The nicotine is also absorbed more slowly and stays in the blood for a longer time.
Newer brands can be just as dangerous
Some smokeless tobacco companies claim that their products are now less harmful because they have lowered the levels of TSNAs, the main cancer-causing chemicals in smokeless tobacco.
There is some evidence that levels are falling, but not in all brands. So we cannot say that modern smokeless tobacco brands are getting safer until clearer regulations are put into place.
Can smokeless tobacco help me quit smoking?
The current medical advice is that you should not use smokeless tobacco to help you quit smoking. Smokeless tobacco can also cause cancer and is highly addictive.
You can increase the chances of successfully quitting smoking by getting professional help. Have a look at our Giving Up page for more advice.
What is snus?
Snus is a special type of smokeless tobacco that is used in Sweden. It is banned in most other countries in the EU. Snus is manufactured using a special process that considerably lowers the levels of TSNAs in the finished product. Because of this, snus may be less dangerous other types of smokeless tobacco.
And it is not clear if snus has any other health risks. For example, one study found that snus increases the risk of pancreatic cancer, but not mouth cancer. And it still contains nicotine so, like all other tobacco products, it is highly addictive.
It is possible that ‘snus’ could be used specifically to help hardcore smokers, who are unlikely to quit through other means, to stop smoking altogether. But before we suggest introducing it in to the UK, more research is needed to see if it would help hardcore smokers to quit. And we must examine other potential intended and unintended effects of introducing it in to the UK.
Cancer-causing chemical found in smokeless tobacco
A chemical in smokeless tobacco products has been found to cause cancer, according to a new study in animals. The chemical was a strong inducer of oral tumors, the study showed.
While use of smokeless tobacco products has been strongly linked to the development of cancer, no specific chemical in the products had been identified as a strong oral-cancer causing agent until now, the researchers say.
The chemical, called (S)-N'-nitrosonornicotine, or (S)-NNN, "is the only chemical in smokeless tobacco known to cause oral cancer," study researcher Silvia Balbo, a cancer researcher at the University of Minnesota, said in a statement. The finding may explain how smokeless tobacco products cause cancer, Balbo said.
Balbo said the findings are an affirmation that tobacco products should be avoided. Smokeless tobacco products are already required to carry warning labels saying the products can cause mouth cancer or are not a safe alternative to cigarettes, the Food and Drug Administration says.
The most common type of smokeless tobacco product is moist snuff placed in the mouth.
Previous studies have suggested that a group of chemicals called nitrosamines, of which (S)-NNN is a member, cause various types of cancer in animals, but no study has looked at the carcinogenicity of (S)-NNN specifically, the researchers say.
Balbo and colleagues administered (S)-NNN to 24 rats. The rats were given (S)-NNN or tap water. The total dose was approximately equivalent to the amount of (S)-NNN to which a smokeless tobacco user would be exposed from chronic use of these products.
All 24 rats given (S)-NNN had esophageal tumors and oral tumors, and died within 17 months.
"Measures should be taken to reduce this chemical in smokeless tobacco," Balbo said.
In future studies, Balbo said she and her colleagues hope to identify other carcinogens in smokeless tobacco, and to understand what levels of these chemicals are present in smokeless tobacco products.
Source:
No comments:
Post a Comment