Smoking (Number-One Risk)

Reviewed by: HU Medical Review Board | Last reviewed: July 2015. | Last updated: May 2018

What is the link between tobacco smoking and COPD?1,2

Tobacco smoking is the leading cause of chronic obstructive pulmonary disease (COPD) worldwide. The majority of people with COPD are current or former smokers. There is a huge amount of evidence that links tobacco smoking with COPD:

  • Between 15% and 20% of smokers develop the disease.
  • Up to 90% of COPD cases are the result of lung damage caused by smoking.
  • About 75% of people with Stage II, III, or IV COPD are current or former smokers.
  • Tobacco smoking is the cause of 90% of deaths that are related to COPD.

The risk of developing COPD gets higher the more years a person smokes, and the more they smoke per day. However, the good news is that it is never too late to stop smoking and experience the many benefits of quitting.

How does smoking cause COPD?2,3

When people smoke tobacco, they breathe tiny particles of irritants into their lungs each time they inhale the smoke. This has two damaging effects:

  • The bronchial tubes (also called “airways”) become swollen and inflamed.
  • The lining of these airways produces a larger amount of mucus to trap the irritants.

The combined result of these effects is that the airways become thickened and narrowed because of the swelling and mucus. This reduces the amount of air that can flow through them. The increased amount of mucus also causes a persistent cough, in an attempt to clear the airways. Over a period of time, this constant irritation and inflammation in the airways causes many smokers to develop COPD.

If a smoker is also regularly exposed to other kinds of irritants that can cause COPD, then his or her risk of is even higher. For example, smokers who also work in an environment where they are exposed to toxic fumes, chemicals, or dusts have a much higher chance of getting COPD than their co-workers who do not smoke.

Smoking cigarettes is not the only way to be exposed to tobacco smoke. Inhaling the smoke from pipes and cigars is also damaging. People also have a higher risk of COPD if they have had long periods of exposure to other people’s tobacco smoke at home or at work – this is called “second-hand smoking” or “passive smoking.”

Evidence also shows that women who smoke experience worse respiratory symptoms than men who smoke the same amount. This means that female smokers may be more likely to develop COPD than male smokers.

Can COPD be caused by exposure to tobacco smoke in early life?3

For some people, being exposed to tobacco smoke during early life can also lead to a higher chance of developing COPD as an adult. Researchers think that being regularly exposed to tobacco smoke before adulthood may keep a person’s lungs from growing to their full capacity. For example, babies born to mothers who smoked during pregnancy have a higher risk of COPD, as do children who grew up in homes with smokers. People who started smoking when they were teenagers are also more likely to develop COPD.

Why should I stop smoking now?3,4

Anyone with COPD can benefit from quitting smoking – even people with severe COPD.
Quitting smoking will not undo the lung damage caused by COPD, but it can slow down the progression of the disease.. However, continuing to smoke almost always causes COPD to get worse.

After quitting smoking, COPD symptoms usually become less frequent and less severe. This is because a non-smoker does not have the constant swelling and irritation in their airways that smoking causes.

All people lose lung tissue as they age, but smokers lose the tissue much more quickly. After stopping smoking, a former smoker’s rate of lung tissue loss can return to that of a non-smoker.

Of course, smoking does not just cause COPD. It also causes other serious conditions like lung cancer, heart disease, and stroke. Quitting smoking now is the most effective way to:

  • Lessen your COPD symptoms
  • Improve your quality of life
  • Lower the rate of lung tissue loss
  • Prevent COPD from getting worse
  • Lower your risk of other severe and life-threatening health problems

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