Smoking is the most important cause of preventable illness, disability and premature death in Canada.

More than 37,200 people will die this year in Canada due to smoking.

Tobacco smoke contains more than 4,000 chemicals.  Many are known to be harmful substances, including tar, nicotine, carbon monoxide, benzene, formaldehyde and hydrogen cyanide.

More than 50 of these chemicals cause cancer.

Most smokers want to quit, but find it very difficult. Most former smokers made at least one unsuccessful quit attempt before finally succeeding and many had to try repeatedly

Nicotine is the drug in tobacco that makes smoking a powerful addiction. Experts rank nicotine ahead of alcohol, cocaine and heroin with regard to the severity of dependence resulting from its use.

Some users of smokeless tobacco (chewing tobacco and snuff) also find it very hard to quit.

While the health risks are highest among heavy smokers and long-term smokers, no user of tobacco escapes risk, including users of smokeless tobacco (chewing tobacco and snuff).

Young people who smoke or use smokeless tobacco are at immediate risk of a range of health problems, including nicotine addiction, increased cough, phlegm, and wheezing, reduced lung function and a worsening of problems from asthma.

Those who start to smoke at an early age are more likely to develop severe levels of nicotine addiction than those who start later, and they are at higher risk of health consequences in adult life.

As well, non-smokers, both children and adults, can be harmed by environmental tobacco smoke generated by other people's smoking.

There is strong evidence that smoking is related to more than two-dozen diseases and conditions. Many organs and body systems are adversely affected by tobacco smoke. Fortunately, most of this starts to reverse after a smoker quits smoking.

All smokers are at extra risk for:

• Coronary heart disease (e.g., heart attacks)
• Peripheral vascular disease (circulatory problems)
• Aortic aneurysm
• High cholesterol (LDL)
• Lung cancer
• Cancer of the mouth, throat and voice box
• Cancer of the pancreas
• Cancer of the kidney, and urinary bladde
• Chronic obstructive pulmonary disease (COPD
• Chronic bronchitis
• Emphysema
• Pneumonia
• Influenza (the "flu")
• The common cold
• Peptic ulcers
• Chronic bowel disease (Crohn's disease)
• Tooth decay (cavities)
• Gum disease
• Osteoporosis
• Sleep problems (falling asleep inappropriately and/or frequent waking)
• Cataracts
• Thyroid disease (Grave's Disease)
  

Smoking is an important cause of heart disease, stroke, and diseases of the blood vessels. Many of these deaths are premature (before the age of 70).

Smoking is a major risk factor that contributes to a form of heart disease called cardiovascular disease. Cardiovascular disease is a major cause of death in Canada.

Smoking is a major risk factor for heart attacks and sudden cardiac death. Smoking also increases the risk of recurrence in persons who have survived a heart attack.

Smoking is also the most powerful risk factor for plaque formation (atherosclerosis) involving the arteries of the legs (peripheral vascular disease). This condition leads to leg pain, difficulty in walking, gangrene and, ultimately, loss of limb.

An estimated 19,900 deaths due to lung cancer will occur in Canada in 2007, and an estimated 23,300 new cases of lung cance will be diagnosed this year alone.

Smoking causes cancer of the lung, oral cavity, pharynx, larynx, esophagus, pancreas, kidney, bladder and cervix. Recent evidence links smoking with cancer of large intestine and some forms of leukemia.

Most deaths from lung cancer are caused by smoking

Although other factors can cause lung cancer, smoking is responsible for 85% of all new cases of lung cancer in Canada.

In 1993, for the first time, lung cancer exceeded breast cancer deaths in Canadian women. Recent research suggests that, for the same amount of smoking, women may be more susceptible than men to the development of lung cancer.

Lung cancer is a highly lethal disease; only a small minority of patients are alive five years after diagnosis.

The causal relationship between smoking and cancers of the mouth, pharynx, larynx, and esophagus has been established for many years. Smokeless tobacco also causes cancer of the mouth.

Like all tobacco-caused diseases, the risk increases with amount and duration of smoking. Alcohol consumption is also a risk factor for these cancers, and the combination of alcohol consumption and smoking results in a greatly increased risk.

Recent studies confirm earlier findings of a strong link between smoking and cancer of the pancreas and with cancer of the kidney and bladder.

Recent findings also suggest that smoking may be a previously unrecognized cause of cancer of the large intestine (colorectal cancer) in both men and women. Evidence is also growing concerning a link between smoking and some forms of leukemia.

Your lungs hold on to 85 to 99% of almost all of the things you inhale.

Respiratory problems can include increased coughing, phlegm, wheezing, chest colds and shortness of breath, even in smokers who smoke as little as one cigarette a week.

Smoking is known to have an effect on babies before they are born.

Smoking has a direct effect on the growth of the fetus. The more the mother smokes during pregnancy, the lower the weight of the newborn infant. Smoking mothers give birth to infants who can weigh about 150 grams less than a term than non-smokers. Such babies, called "low birthweight" babies, are more likely to suffer adverse outcomes, including stillbirth, the need for special treatment in neonatal intensive care units and death in infancy.

During pregnancy, smokers have a greater risk of miscarriages. During the birth they are more likely to have complications. The chances of a baby's dying at birth or shortly thereafter are increased if the mother has smoked during pregnancy.

More than 18% of all deaths from Sudden Infant Death Syndrome (SIDS) are due to maternal tobacco use.

Nursing mothers can pass along harmful chemicals from cigarettes to their babies in breast milk.

Peptic ulcer disease is more likely to occur in smokers than in non-smokers. When ulcers are present, they heal less rapidly in smokers and are more likely to recur.

Evidence is accumulating that smoking is a risk factor for the occurrence of chronic bowel disease (Crohn's disease). As well, smoking may contribute to the recurrence of this disease.

Several recent reports provide strong evidence of an association between smoking and osteoporosis (decreased bone density), which, in turn, predisposes a person to bone fractures. Smoking is independently associated with decreased bone density of the lumbar spine and hip, in both younger and older persons.

In a recent large epidemiologic study, smoking was linked to sleep disturbance. Smoking was associated with difficulty in falling asleep and with symptoms suggestive of sleep fragmentation in both men and women.

Evidence of a link between cataracts and smoking continues to grow. An association may also exist between smoking and a type of thyroid disease (Graves' disease).

Smoking may be a detriment to physical fitness, even among relatively fit, young individuals. One recent study suggests that smokers have lower physical endurance than non-smokers, when differences in average exercise levels are taken into account. Smoking reduces the ability of the blood to carry oxygen and increases the heart rate and basal metabolic rate, thus counteracting the benefits of physical activity, including cardiovascular fitness.

Smoking decreases blood flow in the small vessels of the skin, perhaps damaging skin components, and leading to skin wrinkling and an appearance of premature aging in both men and women.

Low-yield cigarettes aren't necessarily less hazardous. Many smokers compensate for the lower tar and nicotine levels by smoking more cigarettes, taking more puffs on each cigarette smoked, inhaling more deeply, smoking more of the cigarette and blocking the air dilution vent holes on the filter with their lips or fingers.

The best bet for a person's health is to quit.

Along with smoking there are other types of tobacco, this includes smokeless tobacco as well as chewing tobacco and snuff, contain many of the same harmful and addictive substances as cigarettes, pipes and cigars. Smokeless tobacco is a major cause of cancer of the mouth and throat. Along with that it can also cause major dental problems such as recession of the gums, tooth loss and discoloration of the teeth and gums.

For more information check out Health Canada's website.