Risk factors
Risk factors are anything that affects an individual’s chance of getting a disease such as cancer. Gender, age, family history, your social and physical environment, your mental health are all risk factors that can influence whether or not you get cancer. Risk factors cannot determine everything, having one or more known risk factors does not guarantee you will get lung cancer and, furthermore, sometimes people who will do not display any known risk factors will be diagnosed.
Tobacco smoke
Smoking is the leading risk factor for lung cancer. It is thought that at least 80 per cent of lung cancer deaths are the result of smoking [21]. Smoking is also known to increase the chance of developing cancer of the mouth and throat, leukemia, bladder cancer, stomach cancer, kidney cancer, pancreatic cancer and cervical cancer [22]. The more cigarettes you smoke the more it will increase your likelihood of lung cancer. The length of time you have been a smoker is even more important—consequently, starting to smoke at a younger age is more harmful than if you start as an adult [23].
Breathing in the smoke of others, or secondhand smoking, can also increase your risk of developing your risk of lung cancer. It is challenging to determine how much occasional exposure to secondhand smoke will increase your likelihood of lung cancer [24]. In general, however, the more exposure a person receives the higher their risk of lung cancer. Heavy exposure to environmental tobacco smoke at work has been shown to double the risk of lung cancer [25].
Radon
Radon is a colourless, odourless, tasteless radioactive gas found naturally in the environment. It is released into the air during the natural breakdown of uranium in rocks and soil. Once released, radon breaks down into radioactive elements that can attach to dust and other substances in the air we breathe. It’s also a common type of radiation exposure [26].
Radon as a risk factor depends on your level and length of exposure and can develop years later. The Canadian Cancer Society estimates that around 3,000 Canadians will die of lung cancer each year due to radon exposure [27]. It is the leading cause of lung cancer among non-smokers.
Indoor air can contain high levels of radon when it seeps into the home from the rocks and soil surrounding the area. It builds up in spaces that are poorly ventilated and this can include your workplace. Underground workers may also be at risk of radon exposure. If you are concerned about radon exposure, you can use a radon detection kit to test the levels in your home [28].
Asbestos
Asbestos is a group of minerals used widely in building materials and many industries. Exposure to asbestos fibres increases the risk of lung cancer. In particular, workplace exposure to asbestos: people who worked in mines, mills, textile plants, construction, and shipyards are several times more likely to die of lung cancer [29]. Secondary exposure may also occur as a result of asbestos fibres transferring onto work clothing or skin [30]. Asbestos is still present in many home older buildings and homes and if disturbed by deterioration, demolition or renovation it can be released into the air.
It is still not clear to what extent low-level or short-term exposure to asbestos might raise lung cancer risk [31].
Studies have shown that the combination of smoking and asbestos is even more dangerous as smokers who are exposed to asbestos are at even great risk of developing lung cancer. Smokers and non-smokers exposed to asbestos also have a greater risk of developing mesothelioma, a type of cancer that starts in the lining surrounding the lungs (pleura) [32].
In recent years, government regulations have greatly reduced the use of asbestos in commercial and industrial products. However, the federal government continues to use asbestos-containing materials in the construction and renovation of federal buildings, even though asbestos is a known carcinogen and toxin [33].
Exposure to certain chemicals
As well as asbestos, substances found in some workplaces such as arsenic, diesel exhaust and certain forms of silica and chromium can increase the risk of lung cancer. Similarly, if you are a smoker and are exposed to these chemicals your risk is even higher [34]. However, these instances are rare causes of lung cancer because an individual would normally only encounter these chemicals as part of their occupation.
People who work in rubber manufacturing, iron and steel founding and painting also have a higher risk of lung cancer. These industries use many chemicals, but the exact ones that increase the risk of lung cancer are not known [35].
Personal or family history of lung cancer
People who previously have had lung cancer are at an increased risk of recurrence (the lung cancer returning).
First-degree relatives (siblings, children or parents) of people who have had lung cancer may have a slightly higher risk of developing lung cancer themselves. The increased risk among first-degree relatives could be due to a number of factors, such as shared behaviours (like smoking) or living in the same place where there are carcinogens (like radon).
Studies of families with a strong history of lung cancer have found that the increased risk might be due to a mutation in a lung cancer gene. Other studies have shown that the risk of lung cancer in a family increases if a family member developed the disease at an early age.
[36] Information taken from the Canadian Cancer Society
Previous lung disease
If you have had a lung disease that caused scarring in the lungs, you may be at an increased risk for lung cancer. For example, tuberculosis (TB) can form scar tissue in the lung and people who have had TB have double the risk of lung cancer for more than twenty years [37]. Another condition to be aware of is chronic obstructive pulmonary disease (COPD), a long-term disease (including chronic bronchitis and emphysema) that damages the lungs and is usually caused by smoking [38. Chlamydia pneumoniae (a type of bacteria) can also cause chest infections. Some studies have shown that people with antibodies to chlamydia pneumoniae have an increased risk of lung cancer [39].
Outdoor air pollution
There is strong evidence that exposure to outdoor air pollution causes lung cancer. The risk for lung cancer increases with the level of exposure to air pollution. Pollutants in the air vary from region to region depending on sources of emissions in the area. Emissions can also move in from other regions [40].
To find out more about the risk factors of lung cancer, please visit the Canadian Cancer Society
References
[21] “What Are the Risk Factors for Lung Cancer?” American Cancer Society. American Cancer Society, 06 Feb. 2015. Web. 02 Feb. 2016.
[22] “Lung Cancer.” Lung Cancer Canada. Lung Cancer Canada, 2015. Web. 02 Feb. 2016
[23] “Lung Cancer Risks and Causes.” Cancer Research UK. Cancer Research UK, 23 May 2014. Web. 02 Feb. 2016.
[24] “Risk Factors for Lung Cancer.” Canadian Cancer Society. Canadian Cancer Society, n.d. Web. 02 Feb. 2016.
[25] “Lung Cancer Risks and Causes.” Cancer Research UK. Cancer Research UK, 23 May 2014. Web. 02 Feb. 2016.
[26] “What Are the Risk Factors for Lung Cancer?” American Cancer Society. American Cancer Society, 06 Feb. 2015. Web. 02 Feb. 2016.
[27] Gulli, Cathy. “Smoke-free? The New Lung Cancer Doesn’t Care.” Maclean’s. Maclean’s, 19 Jan. 2016. Web. 29 Jan. 2016
[28] “Radon.” Canadian Cancer Society. Canadian Cancer Society, n.d. Web. 02 Feb. 2016.
[29] “What Are the Risk Factors for Lung Cancer?” American Cancer Society. American Cancer Society, 06 Feb. 2015. Web. 02 Feb. 2016.
[30]Reporter, Telegraph. “Widow ‘poisoned by Husband’s Asbestos Hugs'” The Telegraph. Telegraph Media Group, 28 Jan. 2016. Web. 02 Feb. 2016
[31] “What Are the Risk Factors for Lung Cancer?” American Cancer Society. American Cancer Society, 06 Feb. 2015. Web. 02 Feb. 2016.
[32] ibid.
[33] Ireton, Julie. “Federal Government Still Using Asbestos in New Construction.” CBCnews. CBC/Radio Canada, 02 Feb. 2016. Web. 02 Feb. 2016.
[34] “What Are the Risk Factors for Lung Cancer?” CDC. Centers for Disease Control and Prevention, 01 Dec. 2015. Web. 03 Feb. 2016.
[35] “Risk Factors for Lung Cancer.” Canadian Cancer Society. Canadian Cancer Society, n.d. Web. 03 Feb. 2016.
[36] ibid.
[37] “Lung Cancer Risks and Causes.” Cancer Research UK. Cancer Research UK, 23 May 2014. Web. 03 Feb. 2016.
[38] “Risk Factors for Lung Cancer.” Canadian Cancer Society. Canadian Cancer Society, n.d. Web. 03 Feb. 2016.
[39] “Lung Cancer Risks and Causes.” Cancer Research UK. Cancer Research UK, 23 May 2014. Web. 03 Feb. 2016.
[40] “Risk Factors for Lung Cancer.” Canadian Cancer Society. Canadian Cancer Society, n.d. Web. 03 Feb. 2016.