WHAT IS TOBACCO?

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:

Nicotine - the stimulant drug in tobacco smoke that causes dependency, as it is highly addictive. Nicotine is a poison.
Tar – released when the cigarette is burnt and clogs the lungs and causes or stimulates cancer.
Carbon monoxide – a gas that is absorbed by the lungs more readily than oxygen, robbing the body of this vital component and making the blood sticky.

Forms of tobacco

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.

EFFECTS

Short-term effects

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:

initial stimulation, then reduction in brain and nervous system activity
enhanced alertness and concentration
mild euphoria
feelings of relaxation
increased blood pressure and heart rate
decreased blood flow to body extremities like the fingers and toes
nausea, watery eyes and acid in the stomach
decreased appetite, taste and smell.

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.

Long-term effects

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:

lips
tongue
mouth
nose
oesophagus
pharynx
larynx
pancreas
bladder
cervix, and
anus.

Other cancers, including those of the stomach, kidney, liver and blood, have also been linked to smoking.

Secondhand Smoke

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.

Pregnancy

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:

Low birth weight
Spontaneous abortion
Higher risk of SIDS
Ectopic pregnancy
Still birth
Pregnancy and labour complications.

Withdrawal

Common withdrawal symptoms experienced by people quitting smoking include:

Depressed mood
Insomnia
Irritability, frustration, anger
Anxiety
Difficulty concentrating
Restlessness
Decreased heart rate
Increased appetite or weight gain
Fatigue
Constipation
Diarrhoea
Headaches
Dizziness
Coughing
Tingling sensations in extremities
Mouth ulcers
Cravings/urges to smoke.

Some of these symptoms take longer than others to pass or lessen in intensity.

Benefits of Quitting

Let’s take a moment

TIME SINCE QUITTING	BENEFITS
20 minutes	Heart rate reduces.
8 hours	Nicotine level reduces by half, oxygen levels return to normal in blood.
12 hours	Blood level of carbon monoxide reduces dramatically.
24 hours	Carbon monoxide is eliminated from body. Lungs start to clear mucus and other smoking debris.
48 hours	Nicotine is eliminated from body. Taste and smell improve.
2 weeks-3 months	Heart attack risk begins to reduce, lung function and circulation improves.
1-9 months	Coughing and shortness of breath decrease.
1 year	Risk of coronary heart disease is halved after one year compared to continuing smokers.
5 years	Stroke risk is reduced to that of a non-smoker 5-15 years after quitting. Risk of cancers of the mouth, throat, oesophagus decreases.
10 years	Risk of lung cancer death is about half that of a continuing smoker and continues to decline. Risk of cancers of the bladder, kidney and pancreas decreases.
15 years	Risk of coronary heart disease is the same as a non-smoker. The all-cause mortality in former smokers declines to the same level as people who have never smoked

Other benefits of quitting include:

risk of having a lower birth weight baby drops to normal if the mother quits before becoming pregnant or during the first trimester
senses of smell and taste improve
appearance of skin improves
fitness improves
money saved – a person smoking a pack of cigarettes per day at a cost of $12 could save $84 a week, $4380 a year and $21 900 over 5 years.

References

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.