Most scientists agree that these things affect the risk of lung cancer.
- Age
- Air pollution
- Family history
- Fruits and vegetables
- Second-hand smoke
- Tobacco use: cigarettes
- Tobacco use: cigars and pipes
- Workplace chemicals
Age
The risk of lung cancer goes up with age. Rates of the disease are low in people under 40; they then increase significantly from age 40 until after 75.
Air pollution
People who live in a big city for 10 or more years have a slightly higher risk of lung cancer. This is most likely due to pollutants in the air, like car exhaust and factory emissions, that cause damage to the cells in the lungs and airways.
Family history
People who have a close relative (father, mother, brother or sister) with lung cancer have a higher risk of the disease. This is because some cases of lung cancer are linked to mutations in the genetic structure (DNA) of the body's cells that can be passed from generation to generation.
Fruits and vegetables
People who eat at least 5 servings of fruits and vegetables a day have a lower risk of lung cancer. Scientists don’t know exactly which factors provide the protection because fruits and vegetables contain many different combinations of healthy elements like antioxidants.
1 serving is:
- 1 cup of raw leafy greens like lettuce or spinach
- 1 medium-sized piece of fruit or 1/2 cup of small or cut-up fruit
- 1/2 cup of cooked beans or peas
- 1/2 cup of other vegetables, raw or cooked
- 1/4 cup of dried fruit
- 3/4 cup of 100% fruit juice
People who eat fruits and vegetables also have a lower risk of heart disease, diabetes and stroke.
Second-hand smoke
People who are exposed to second-hand smoke (the smoke from other people’s cigarettes, cigars and pipes) have a higher risk of lung cancer, even if they don’t smoke themselves. Second-hand smoke contains dangerous chemicals that damage the genetic structure (DNA) of your body's cells, and this damage can lead to cancer.
Tobacco use: cigarettes
People who smoke cigarettes have a much higher risk of lung cancer. In fact, 90% of people who get lung cancer are smokers. Cigarette smoke contains dangerous chemicals that damage the genetic structure (DNA) of the cells in the lungs and airways, and this damage can lead to cancer. The more a person smokes, the higher the risk of lung cancer.
Taking beta-carotene supplements can further boost lung cancer risk in smokers. So most smokers should avoid the supplement. Talk to a doctor if you have any questions about your risk.
In addition to lung cancer, people who smoke also have a higher risk of many other types of cancer, including leukemia and cancers of the lip, mouth, larynx, esophagus, bladder, kidney, stomach, and pancreas. Smokers also have a higher risk of diseases like heart disease, diabetes, bone loss (osteoporosis), emphysema, and bronchitis!
Tobacco use: cigars and pipes
People who smoke cigars (even if they don't inhale) also have a higher risk of cancers of the voice box, esophagus and oral area (lip, mouth, tongue and throat). And they have a higher risk of heart disease and stroke.
People who smoke cigars or pipes have a higher risk of lung cancer than non-smokers. Like cigarette smoke, cigar and pipe smoke contains dangerous chemicals that damage the genetic structure (DNA) of the body’s cells, and this damage can lead to cancer. The more a person smokes, the higher the risk of lung cancer.
Workplace chemicals
Workplace chemicals linked to lung cancer include asbestos, radon and chromium. Processes like arsenic smelting are also linked to lung cancer.
People who are exposed to certain workplace chemicals have a higher risk of lung cancer. This is because some chemicals can damage the genetic structure (DNA) in the body's cells, and this damage can lead to cancer.
In addition, taking beta-carotene supplements can further boost lung cancer risk in people exposed to workplace chemicals. So most people exposed to such chemicals should avoid the supplement. Talk to a doctor if you have any questions about your risk.
Other risk factors
Some other things increase lung cancer risk, but they increase the risk far less than smoking. They are:
- Exposure to radon gas
- Lowered immunity
- Past cancer treatment
- Previous lung disease
Exposure to radon gas
Radon gas is a naturally occurring radioactive gas that can seep out of the soil into buildings. This is more likely in certain parts of the UK where there is a lot of granite, for example in the West Country and the Peak District. Radon is the second biggest cause of lung cancer after smoking. The risk from radon increases the risk from smoking. Smokers with high indoor levels of radon have a particularly high risk of getting lung cancer. If you are worried about this, the Health Protection Agency - Radiation Protection Division has information on how to check radon levels in your house.
Lowered immunity
HIV and AIDs lower immunity and so do drugs that people take after organ transplants. An overview of research studies shows that people with HIV or AIDS have a risk of lung cancer that is 3 times higher than people who do not have HIV or AIDS. People who take drugs to suppress their immunity after an organ transplant have double the usual risk of lung cancer.
Past cancer treatment
There is some evidence that particular cancer treatments might increase your risk of lung cancer. Researchers in Sweden looked at the medical records of 140,000 breast cancer patients. They found that there seemed to be an increased risk of lung cancer between 5 and 20 years after breast cancer treatment. They think this may be due to smoking after having had radiotherapy to the chest. This is backed up by the results of two studies showing particularly high risks of lung cancer in women who smoked and had radiotherapy for a previous breast cancer. The studies found no increase in risk in non smokers treated with radiotherapy for breast cancer.
Treatment for other types of cancer has also been linked to a slightly increased risk of lung cancer years later. People who have had treatment for Hodgkin's lymphoma, some types of non Hodgkin's lymphoma, or testicular cancer may have an increased risk of lung cancer. But it is important to remember that having any of these cancers is a much greater risk to your health than the slight increase in cancer risk from treatment. It is most important to get the treatment you need at the time. In some of this research, lung cancer risk seems to be increased even more in smokers, so if you have had radiotherapy to your chest it is very important not to smoke.
Previous lung disease
Having had a disease that caused scarring in the lungs may be a risk factor for a type of lung cancer called adenocarcinoma of the lung. Tuberculosis (TB) can make scar tissue form in the lungs. A recent study in China showed that people who have had TB have a higher risk of lung cancer.
Chlamydia pneumoniae is a type of bacteria that can cause chest infections. Some studies have shown that people with antibodies to chlamydia pneumoniae have an increased risk of lung cancer. The antibodies show that these people have had this infection. But other studies have not shown an increased risk so we don't know for sure whether chlamydia pneumoniae can cause lung cancer.