3.32 Health effects of smoking other substances

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3.0 Background

3.1 Tobacco—a leading preventable cause of death and disease

3.2 Cardiovascular diseases

3.3 Lung cancer

3.4 Respiratory diseases

3.5 Other cancers caused by or associated with smoking

3.6 Reproductive health and smoking

3.7 Pregnancy and smoking

3.8 Infant health and smoking

3.9 Increased susceptibility to infection in smokers

3.10 Eye diseases

3.11 Dental diseases

3.12 Gastrointestinal diseases

3.13 Bone density and risk of fractures

3.14 Effects of smoking on the skin

3.15 Smoking and complications in medical treatment

3.16 Smoking and diabetes

3.17 Poorer levels of general health

3.18 Smoking, motor vehicle crashes and other injuries

3.19 Burns and fires caused by tobacco use

3.20 Tobacco poisoning

3.21 Health effects for younger smokers

3.22 Genetic influences on tobacco-caused disease

3.23 Smoking, dementia and cognitive decline

3.24 Lung disease, smoking and occupational exposures

3.25 Air pollution, cigarette smoking and ill health

3.26 Health effects of smoking brands that claim to deliver lower levels of tar, nicotine and carbon monoxide

3.27 Health effects of smoking tobacco in other forms

3.28 Health 'benefits' of smoking?

3.29 Morbidity (ill health) attributable to tobacco-caused disease

3.30 Deaths attributable to tobacco by disease category

3.31 Morbidity and mortality due to tobacco-caused disease and socioeconomic disadvantage

3.32 Health effects of smoking other substances

3.33 Health effects of chewing tobacco, and of other smokeless tobacco products

3.34 Public perceptions of tobacco as a drug, and knowledge and beliefs about the health consequences of smoking

3.35 Health benefits of cessation

3.36 The global tobacco pandemic

Acknowledgments

References

This section is not intended to provide a comprehensive overview of drug use other than tobacco, but to demonstrate that the deliberate inhalation of smoke from the combustion of any matter is injurious to health. The health effects of smoking any substance will depend on the age at which smoking commences, the duration for which the body is exposed to the smoke, and the concentration and nature of constituents of the material smoked.

The scientific literature describing the health effects of smoking tobacco is comprehensive because of the relatively large proportion of the population which has used tobacco, the time period over which tobacco has been consumed, and the fact that the legality of tobacco has not inhibited respondents from answering questions about their consumption.

The same cannot generally be said of other smoked substances. In the case of cannabis, its illegality has militated against broad-based population studies, although data gathering has improved with its growing public acceptance (see Chapter 1, Section 1.10). Lack of adequate funding and for medical and epidemiological research is a major factor in some countries where alternative forms of smoking may be more widespread. Less common forms of smoking have been under-researched because their users are too small in number and geographically scattered to have been systematically studied. However the following observations may be drawn:

3.32.1 Herbal and other non-tobacco cigarettes

Herbal and other non-tobacco cigarettes may erroneously be considered as a safer alternative to smoking, or an aid to quitting smoking, and are actively promoted as such by some manufacturers (for example the Honeyrose range, imported from England and available in Australia).191 However, even cigarettes that do not contain tobacco or nicotine still produce toxic substances. An analysis of 'vegetable-based cigarettes' manufactured in France and sold in Austria were found to yield levels of carbon monoxide (CO) at least as high as those produced by conventional cigarettes. Analysis of other constituents of the smoke was not made, although initial studies had shown that combustion may have produced carcinogens and other noxious chemicals.192 Investigations of a different brand of 'non-nicotine, non-tar' herbal cigarettes popular in the Philippines has also shown significant yields of tar and CO.193 Smokers attempting to use herbal cigarettes as an adjunct to quitting are therefore very likely to continue to expose themselves to dangerous tar and CO levels, without actually increasing their chance of quitting.

Cigarettes combining herbs and tobacco have been produced in China since 1959, and they are now manufactured in South Korea, Taiwan and Thailand.194 These cigarettes are commonly promoted with messages that they are aids in quitting, are less harmful than conventional cigarettes, or with claims for active health benefits such as raising immunity or protecting the kidneys. There is no reliable published literature to support any health claims claimed for herbal-tobacco cigarettes,194 and at least one report (from the tobacco industry) has indicated that the tar and nicotine level of Chinese herbal-tobacco cigarettes is very high.195

3.32.2 Cannabis (marijuana, hash, ganja)

The main forms of cannabis are marijuana, hashish and hashish oil. Marijuana comprises the dried leaves, flowering tops and stems of the hemp plant Cannabis sativa. The more concentrated resin from the flowers is called hashish. Cannabis is usually smoked as a cigarette (joint) or in a pipe (bong).196

Cannabis is the most frequently used illegal drug in Australia. In 2007, one in every three Australians aged 14 and over reported having used cannabis at some time in their lives. One in five teenagers between 14–19, half of the population aged between 20–29, and 55% of people aged between 30–39 had tried the substance.197 Continued use may lead to both physical and behavioural addiction, especially among regular, heavy users, and those who start using the substance at an earlier age.198

The substance in cannabis which causes the user to experience a 'high' is THC (?9-tetrahydrocannabinol), which binds to receptors in the brain. In the short term, cannabis use causes difficulty in thinking and problem solving, impaired short-term memory and poorer coordination, and is associated with an increased risk of having motor vehicle accidents. Chronic use of cannabis can lead to damage to cognitive functions, and it is not clear whether these problems reverse after quitting.198 Cannabis smoke also contains a higher concentration of carcinogens than tobacco smoke, and because of a user's tendency to inhale deeply and hold the smoke in for longer, exposure of the lung and airways to toxic chemicals may be far greater per joint of cannabis than per typical tobacco cigarette.196, 199 Long-term, heavy users of cannabis show a higher frequency of inflammatory and pre-cancerous changes to the bronchial tubes than non-users. A recent review of the evidence concludes that there are good grounds for believing that chronic smoking of cannabis carries a significant risk of cancer.198 Cannabis use may also be linked to the development of cardiovascular symptoms, particularly in the predisposed.198

Recent research has found that smoking cannabis has a significant impact on lung structure and function. Cannabis use causes airflow obstruction, impaired large airways function and hyperinflation (overexpansion of the lungs due to reduced elasticity), the effects worsening as the amount smoked increases. One joint of cannabis was found to be equivalent to between 2.5 and five tobacco cigarettes in ability to cause airflow obstruction, probably for the most part due to differences in the way cannabis is smoked, as noted in the previous paragraph, as well as the fact that a joint is generally smoked without a filter and down to a smaller butt length, and the smoke is generated at a higher temperature.199 This study also showed that cannabis smokers experienced respiratory symptoms including wheezing, coughing, phlegm production and chest tightness.199 Over the longer term, using both cannabis and tobacco has an additive effect on respiratory symptoms and lung function. This means that in users of both substances, respiratory symptoms are increased and lung function is worsened to a greater extent than if just one of the two drugs is used.200

There is a large body of evidence supporting an association between cannabis use and the development of various psychiatric disorders, including major depression, anxiety and panic disorders.198 Cannabis use is also linked to an increased likelihood of experiencing psychosis[11] or psychotic symptoms, independent of other contributing factors,201, 202 even in younger users.203 Adolescents who use cannabis also have a greater risk behavioural disorders, poorer psychosocial outcomes198 and educational underachievement.203

Babies born to women who have smoked marijuana during pregnancy have a greater probability of experiencing developmental problems, evident from early schooling through to adolescence.198

3.32.3 Kreteks

Kreteks are cigarettes that contain a combination of cloves and clove oil, tobacco and other additives. Originating in Indonesia, where they account for about 90% of the market,204 a small number of brands are currently imported into Australia.

Although kreteks are smaller than typical cigarettes, they can deliver similar levels of nicotine and carbon monoxide to smokers.205 Long-term research on the health effects of smoking kreteks is scant, but it can be reasonably assumed that they pose at least the same dangers to health as conventional cigarettes.

Research from Indonesia has shown that regular kretek smokers have 13?20 times the risk of abnormal lung function than non-smokers.206 Kretek use is associated with a higher risk of acute lung injury, particularly in susceptible individuals such as those with asthma or respiratory infections.207 Cloves contain a substance called eugenol, which when inhaled has the characteristics of a local anaesthetic. In the past this attribute has lent kreteks a reputation as soothing for sore throats and asthma,204 but in fact it can reduce the gag reflex, leading to pulmonary aspiration (when substances such as food or drink enter the lungs).207

Kreteks are used by about 2% of middle and high-school students in the United States.208 Consumption patterns in Australia are not known.

3.32.4 Bidis (beedis, beedies, biris)

Bidis are small, thin, hand-rolled cigarettes consisting of sun-dried and cured tobacco flakes rolled up in a piece of dried tendu or temburni leaf (from plants native to Asia). They may be flavoured with a variety of sweet or fruit essences, and secured at either end with colourful threads.209 Bidi use is most prevalent in India, Bangladesh, Nepal, Sri Lanka, Pakistan and the Maldives.210 Up to 56% of men in South Asian countries smoke bidis.211 As with kreteks, bidis have gained certain cachet among younger smokers in the United States of America, with about 2% of senior school students reporting current use.209, 212 Bidis have apparently found favour in this population due to their taste and comparative inexpensiveness, as well as the (erroneous) perception that they are a safer alternative to usual manufactured cigarettes.209 More recent research from the USA suggests that use of bidis (and kreteks) has remained a minority behaviour, perhaps because US cigarette companies now market their own flavoured products.212 Australian consumption figures are not known, but are likely to be low.

Smoke from bidis can contain higher levels of nicotine, tar and other toxic chemicals than ordinary cigarettes,213 and bidi smokers inhale two to three times greater an amount of nicotine and tar compared with smoking conventional cigarettes, due to the poor combustibility of the outer bidi wrapper and hence the need to keep puffing on the cigarette in order to keep it alight.211 The compounds added to provide flavouring (such as clove, cinnamon, vanilla, cardamom, strawberry, mango, grape, lemon-lime and chocolate) are also present in high levels and may contribute to long-term damage to health, particularly in the case of cloves.214

Bidi use is certainly no less hazardous than cigarette smoking, and may be more so.215 Bidis cause the same range of smoking-caused disease as conventional cigarettes, including coronary heart disease and oral, respiratory and stomach cancers. Bidi use in pregnancy is associated with perinatal mortality.209 Tobacco factory employees who hand-roll bidis are chronically exposed to potentially toxic levels of tobacco via inhalation of dust and flakes, and through the skin.211