Factors That May Affect the Risk of Cancer
The foods that you eat on a regular basis make up your diet. Diet is being studied as a risk factor for cancer. It is hard to study the effects of diet on cancer because a person's diet includes foods that may protect against cancer and foods that may increase the risk of cancer.
It is also hard for people who take part in the studies to keep track of what they eat over a long period of time. This may explain why studies have different results about how diet affects the risk of cancer.
Some studies show that fruits and nonstarchy vegetables may protect against cancers of the mouth, esophagus, and stomach. Fruits may also protect against lung cancer.
Some studies have shown that a diet high in fat, proteins, calories, and red meat increases the risk of colorectal cancer, but other studies have not shown this.
It is not known if a diet low in fat and high in fiber, fruits, and vegetables lowers the risk of colorectal cancer.
Studies have shown that drinking alcohol is linked to an increased risk of the following types of cancers:
Drinking alcohol may also increase the risk of liver cancer and female colorectal cancer.
Studies show that people who are physically active have a lower risk of certain cancers than those who are not. It is not known if physical activity itself is the reason for this.
Studies show a strong link between physical activity and a lower risk of colorectal cancer. Some studies show that physical activity protects against postmenopausal breast cancer and endometrial cancer.
Studies show that obesity is linked to a higher risk of the following types of cancer:
- Postmenopausal breast cancer.
- Colorectal cancer.
- Endometrial cancer.
- Esophageal cancer.
- Kidney cancer.
- Pancreatic cancer.
Some studies show that obesity is also a risk factor for cancer of the gallbladder.
Studies do not show that losing weight lowers the risk of cancers that have been linked to obesity.
Environmental Risk Factors
Being exposed to chemicals and other substances in the environment has been linked to some cancers:
- Links between air pollution and cancer risk have been found. These include links between lung cancer and secondhand tobacco smoke, outdoor air pollution, and asbestos.
- Drinking water that contains a large amount of arsenic has been linked to skin, bladder, and lung cancers.
Studies have been done to see if pesticides and other pollutants increase the risk of cancer. The results of those studies have been unclear because other factors can change the results of the studies.