The Harmful Health Effects of Smoking

Tobacco remains the leading preventable cause of disease and death in Canada, killing 37,000 Canadians annually.

There are approximately 13,000 tobacco-related deaths each year in Ontario; that's 36 deaths per day.

Nicotine addiction

  • Addiction happens when the human body relies on a substance so much that the body can't function without it. A person who's addicted can't control his or her drug use.
  • Nicotine is the chemical in cigarettes that makes them addictive. Nicotine is considered one of the most addictive substances in the world.
  • Approximately eight out of ten people who try smoking get hooked.

Chemicals in cigarettes

  • Many of the 4,000 chemicals in a single cigarette are known to cause cancer.
  • Cigarettes contain nicotine, tar, carbon monoxide, ammonia, cyanide and formaldehyde.

Sources: Health Canada, The Lung Association, Canadian Centre on Substance Abuse

How cigarette smoke harms the body

  • The chemicals is cigarettes harm many different parts of your body:

    • Tar quickly builds up in the lungs and stops them from functioning properly. The body can't easily remove this build up, which can eventually lead to lung cancer and other respiratory diseases.
    • Smoking doesn't cause only lung cancer. Smokers are also more at risk for cancer of the mouth, sinuses, brain, breasts, bladder and kidney.
    • Carbon monoxide replaces oxygen in the blood system, so less oxygen gets to the lungs, brain, muscles and organs. If you smoke, your heart has to work harder to get enough oxygen to all the parts of your body, leading to heart disease.
  • The combined effect of the chemicals found in cigarettes puts smokers at greater risk for pneumonia, influenza, tooth decay, gum disease, ulcers, emphysema, high blood pressure and high cholesterol.

Sources: Canadian Cancer Society, Health Canada

Effects of sidestream and second-hand smoke

  • Second-hand smoke is the smoke that smokers exhale.
  • Non-smokers are also exposed to sidestream smoke, which comes from the lit end of a cigarette.
  • Children exposed to second-hand and sidestream smoke are at greater risk for bronchitis, ear infections, pneumonia and asthma.
  • The Ontario Medical Association (OMA) has identified second-hand smoke as the third-leading preventable cause of death (behind smoking and alcohol).
  • For a long-term smoker, the chance of dying prematurely from smoking is one in two.
  • Second-hand smoke is especially dangerous to babies and children because their smaller lungs make them breathe in and out more often.
  • Exposure to second-hand tobacco smoke can also be harmful to health.

    • Second-hand smoke can cause lung cancer and heart disease in adults.
    • Children who are regularly exposed to second-hand tobacco smoke have a higher risk of developing bronchitis, pneumonia, ear infections and asthma.

Sources: Health Canada, Ontario Medical Association, Physicians for a Smoke-Free Canada

Youth and smoking

The decision to start smoking has been linked to several key factors including individual characteristics such as age and sex, the immediate social environment (particularly friends and family), and the broader social environment such as school and community.1 Research shows that the younger a person starts smoking, the more difficult it will be to quit later in life.2

Many Canadians start to smoke in their teenage years. In 2011, smokers continued to report that, on average, they smoked their first whole cigarette at the age of 16, and started smoking regularly at 18 years of age. (Statistics Canada)

Smoking in the Movies Can Harm Our Kids

Over the seven years (2005, 2007-2012) where data were available, it is estimated that, on average,13, 241 current smokers in Ontario aged 12-17 were recruited to smoking in a year because of watching smoking in movies. It is projected that, on average, 4,237 of these smokers will die prematurely as a result of tobacco imagery in movies.3

Evidence suggests that when youth see smoking in the movies, they are more likely to begin or continue to smoke. Smoking scenes include:

  • Characters using or handling tobacco (e.g., smoking a cigarette, cigar or pipe, using chewing tobacco or shisha).
  • Tobacco use in the background (e.g., open package of cigarettes, tin of chewing tobacco).

In Canada, on-screen smoking is one of the few ways that smoking is still being promoted to children and youth. Lowering the amount of on-screen smoking that children and youth see is an effective way to help reduce their likelihood of smoking. For more information about tobacco use in the movies and to learn how you can help make movies smoke-free, visit their website at:

Negative side effects of smoking

More negative side effects of smoking include:

  • bad breath
  • yellow-stained fingers and teeth
  • smelly hair and clothes
  • reduced sense of taste and smell
  • premature wrinkles
  • less money (cigarettes are expensive)
  • greater risk of fire

Source: Health Canada


  1. Leatherdale S.T MS. The relationship between student smoking in the school environment and smoking onset in elementary school students. Cancer Epidemiology, Biomarkers & Prevention. 2005; 14(7): 1762 - 1765.
  2. Breslau N, Peterson E. Smoking cessation in young adults: age at initiation of cigarette smoking and other suspected influences. American Journal of Public Health. 1996; 86:215.
  3. Babayan, A, Luk R, Schwartz R. Exposure to Onscreen Tobacco in Movies among Ontario Youth, 2004-2013. Toronto, ON: Ontario Tobacco Research Unit, May 2014.

Revised: Monday May 16 2016

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