3.33 Health effects of chewing tobacco, and of other smokeless tobacco products
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Smokeless tobacco products are those intended to be sucked, chewed or inhaled by the user, rather than burned. In oral use, nicotine from prepared tobacco leaf is absorbed through the lining of the mouth, and in nasal use, through the lining of the nose. Smokeless tobacco products and other orally administered psychoactive substances such as betel quid or areca nut have been long used in South America and South-East Asia, and are now extensively used in many countries.216, 217 Use of these substances is responsible for a significant proportion of the overall burden of morbidity and mortality due to tobacco use.216 The market for smokeless tobacco continues to expand, through promotions aimed at smokers subject to smoking bans who are seeking an alternative means of access to nicotine, among women living in societies in which smoking is not seen as socially acceptable, and in the youth market.218 In Australia, sales and marketing of smokeless tobacco are banned. However loose tobacco is chewed in some Australian Indigenous communities,152, 219, 220 and imported products are available in some South Asian shops221 (see below).
Smokeless tobacco is available in many forms worldwide. Snuff is a cured, ground tobacco which may be may be 'dipped,' that is, held in place in the mouth and sucked, or in its dry form, inhaled. Moist snuff is sold loose, or in ready-to-use, teabag-like pouches designed for sucking. In some countries tobacco pastes or powders are applied to the gums and teeth. Chewing tobacco is available in several varieties, including loose leaf, plug tobacco and twist chewing tobacco.217 In India, Pakistan, Bangladesh and Sri Lanka, tobacco is commonly chewed in combination with other substances, such as betel leaf ('paan'), areca nut and lime.216 Smokeless tobacco products tend to be less expensive than cigarettes, and are often flavoured and sweetened to improve palatability, which adds to their appeal to the youth market.218
Different product types have differing disease profiles, depending on ingredients and manufacturing techniques,222, 223 but all smokeless tobacco products are potentially addictive,222 some delivering higher doses of nicotine than cigarettes.224 The moist snuff pouches available in the USA and the tobacco-betel, tobacco-lime and other tobacco mixtures favoured in South Asia, are known to cause cancers of the head and neck as well as non-malignant oral disease.217, 222 Evidence is emerging that at least some forms of smokeless tobacco may also be implicated with a range of other problems, such as adverse reproductive outcomes,222 and the development of cardiovascular disease.225
A Scandinavian smokeless tobacco product known as 'snus' has attracted a great deal of attention in the past decade. Snus is manufactured and stored by different techniques from other smokeless products, which is thought to affect its toxicity. Used by about 20% of adult males in the region, commonly as an aid in smoking cessation, snus appears not to cause respiratory diseases, but is addictive, and may be associated with other increased disease risk.223 An association between snus use and increased risk of pancreatic cancer has been observed, but to date it appears not to cause cancers of other sites.226 A relationship between snus use and increased risk of experiencing a major cardiovascular event has also been reported, particularly in middle-aged users, but clarification of these findings is required.227 Snus use in pregnancy may be associated with lower birth weight, preterm delivery, and (opposite to smoking) pre-eclampsia.227
Use of snus in place of cigarette smoking may have been responsible for declines in both smoking prevalence228 and rates of tobacco-caused illness in Sweden,223 and epidemiological modelling strongly suggests that if Australian smokers were to switch to snus use, substantial health gains could be realised.229 There is now considerable debate about whether products such as snus may have a wider role in reducing harm caused by smoking.222, 227, 230–232 For further information, refer to Chapter 12.
During the 1980s moist snuff was marketed for a brief period in Australia in ready-to-use, teabag-like suckable pouches, of the kind popular in the USA.233 Smokeless tobacco was subsequently banned in several states during the late 1980s, and federal legislation banned the manufacture, importation and commercial supply of the products in 1991. Subsequent amendments have allowed the importation of up to 1.5kg of smokeless tobacco products for personal use, larger amounts being admissible by permit.234 However, recent evidence that smokeless tobacco products are readily available from South Asian shops in Sydney suggests that current legislation allowing importation of these products is easily exploited and that the law regarding commercial supply is being flouted.221
Some Aboriginal and Torres Strait Islander communities chew nicotine-containing plants according to traditional methods, blending the leaves with ash to facilitate oral absorption of nicotine. Manufactured loose tobacco is also chewed in some communities, with or without the addition of ash.152, 219 The health effects of chewing these specific tobacco mixtures have not been investigated. Tobacco chewing among the Australian Indigenous population is discussed further in Chapter 8, Section 8.5.
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