Although it is undeniable that the majority of people who suffer from lung cancer are smokers or former smokers, this disease also affects non-smokers and can have its source elsewhere than in cigarettes. It may be something in the environment.
Passive smoking
Restrictions on smoking have been in place for many years because passive smoking is one of the main causes of lung cancer in non-smokers. Inhaling cigarette smoke from someone you work or live with is a major factor in developing this dangerous disease. It has been proven that a non-smoker who shares his life with a smoker has a 24% chance of developing this disease after some time.
Heredity
Not all smokers will be diagnosed with the disease. It has even been proven that the parents of people who have already had the disease have a greater chance of developing it themselves, whether they smoke or not. So if you have a sibling or relative who has had the disease, you are 2 or even 3 times more likely to get it, compared to someone whose family has no history of it. However, there is no reason to panic as the risk is still very limited. In fact, only 8% of cancer cases are hereditary.
Oncogenes allow cells to grow and divide, while tumour suppressor genes stop cells from spreading and kill them when they are no longer useful to the body. When these genes mutate and divide to form tumours, that's when cancer starts.
Air pollution
Prolonged exposure to extremely polluted air can cause the development of lung cancer, as can passive smoking. This pollution can be both external and internal. In both cases, the risks of developing cancer and other respiratory diseases are the same. It can be smoke from vehicles, machinery or power stations. But air pollution can also come from natural sources such as wind-blown dust. These substances are a danger to people who are exposed to them, and the number of contaminated individuals is estimated at 2000 per year.