Tobacco comes from the dried leaves of the tobacco plant (Nicotiana tabacum and Nicotiana rustica). The leaf of the tobacco plant is dried, cured and aged before having other ingredients added to manufacture a range of tobacco-based products.
Tobacco smoke is a mixture of almost 4,000 different chemical compounds, including nicotine, tar, carbon monoxide, acetone, ammonia and hydrogen cyanide. Forty-three of these chemicals have been proven to be carcinogenic (causing cancer).
The three major chemical components of tobacco are:
Tobacco is ingested through smoking cigarettes, pipes and cigars. In the form of a fine powder, it may also be sniffed as snuff, or it is sometimes sold in blocks to be chewed. It can also be ingested through passive smoking (termed ‘secondhand smoke’). Cigarettes account for approximately 98% of tobacco consumed in Australia.
Inhaling smoke from cigarettes is an extremely efficient method for delivering nicotine. Nicotine dissolves instantly in saliva, through the lining in the mouth and into the bloodstream in a few seconds. The smoker may experience dizziness and feel light-headed almost immediately. Other short-term effects include:
Nicotine reduces tension in muscles, which can make the smoker feel relaxed. It seems to help some people work by improving concentration, relieving boredom and fatigue.
Many smokers believe smoking calms their nerves. However, smoking releases epinephrine, a hormone that creates physiological stress in the smoker, rather than relaxation. The addictive quality of the nicotine contained in the cigarette makes the user smoke more to calm down; when in fact the smoking itself is causing the agitation.
Tobacco smoking remains the leading preventable cause of death and illness in Australia. The Australian Institute of Health and Welfare estimates that smoking accounts for 15,000 deaths annually (AIHW 2007). In NSW, more than 6,000 deaths and 55,000 hospitalisations are attributable to smoking each year. Half of all smokers will die from tobacco-related disease.
Tobacco smoking is a proven risk factor for a range of fatal and debilitating diseases and conditions. These include cardiovascular disease, stroke and cancer.
Smoking is widely recognized as causing lung cancer but it also increases the risk of cancer of the:
Other cancers, including those of the stomach, kidney, liver and blood, have also been linked to smoking.
Secondhand smoke is the term commonly used to describe the environmental smoke that is a by-product of active smoking. It consists of smoke that has been exhaled by the smoker (exhaled mainstream smoke) and smoke drifting from the smouldering tip of the cigarette (sidestream smoke). Most secondhand smoke is comprised of sidestream smoke, as smokers will generally only take a few puffs while the cigarette smoulders. Compared with inhaled smoke, secondhand smoke contains more nicotine, carbon monoxide, particulate matter and other carcinogens.
Secondhand smoke can cause cardiovascular disease, lung cancer, respiratory tract irritation, and an increased risk of bronchitis, pneumonia, and early onset of asthma in children. It also increases the risk of sudden infant death syndrome (SIDS) and the frequency and severity of asthma symptoms. A child living with parents who smoke can inhale the equivalent of 80 cigarettes a year.
Smoking has a negative impact on both the mother and the unborn child. This is due to the supply of oxygen to the baby being reduced from carbon monoxide in cigarette smoke. Blood flow to the uterus, placenta and foetus is also affected, due to nicotine's constricting effect on the uterine and umbilical arteries. Other toxins from tobacco smoke also reach the foetus. Cadmium, a carcinogen, accumulates in the placenta and has been detected in umbilical cord blood.
Some of the possible health risks include:
Common withdrawal symptoms experienced by people quitting smoking include:
Some of these symptoms take longer than others to pass or lessen in intensity.
Let’s take a moment
Other benefits of quitting include:
NSW Health (2005). Let’s Take a Moment: Quit Smoking Brief Intervention – A Guide for all Health Professionals. Sydney: NSW Health.
Scollo, MM and Winstanley, MH [ed] (2008). Tobacco in Australia: Facts and Issues. Third Edition. Melbourne: Cancer Council Victoria.