Stomach Cancer Risk Factors

A risk factor is anything that raises your chances of getting a disease such as cancer. Different cancers have different risk factors. Some risk factors, like smoking, can be changed. Others, like a person’s age or family history, can’t be changed.

But having a risk factor, or even several risk factors, does not mean that you will get the disease. Many people with 1 or more risk factors never get cancer, while others who get cancer may have had few or no known risk factors.

Several risk factors make a person more likely to get stomach cancer. Some of these can be controlled, but others cannot.

Being male

Stomach cancer is more common in men than in women.

Being older

Stomach cancer can develop in younger people, but the risk goes up as a person gets older. Most people diagnosed with stomach cancer are in their 60s, 70s, or 80s.

Race/ethnicity

In the United States, stomach cancer is more common in Hispanic American, African American, Native American, Asian American, and Pacific Islander people than it is in non-Hispanic White people.

Geography

Worldwide, stomach cancer is more common in East Asia, Eastern Europe, and South and Central America. This disease is less common in Africa and North America.

Helicobacter pylori infection

Infection with Helicobacter pylori (H pylori) bacteria is a major cause of stomach cancer, especially cancers in the lower (distal) part of the stomach. Long-term infection of the stomach with this germ can lead to atrophic gastritis and other precancerous changes of the inner lining of the stomach (see above).

People with stomach cancer have a higher rate of H pylori infection than people who don’t have this cancer. H pylori infection is also linked to some types of lymphoma of the stomach. Even so, many people are infected with H pylori, and most people who carry this germ in their stomach never develop cancer.

Having excess body weight

Having excess body weight is linked with an increased risk of cancers of the cardia (the upper part of the stomach near the esophagus).

Diet

Stomach cancer risk is increased in people whose diets include large amounts of foods preserved by salting, such as salted fish and meat and pickled vegetables.

Eating processed, grilled, or charbroiled meats regularly appears to increase the risk of non-cardia stomach cancers.

Eating few or no fruits likely increases the risk of stomach cancer. On the other hand, eating lots of fresh fruit, especially citrus fruits, appears to lower the risk of stomach cancer.

Alcohol use

Drinking alcohol probably increases the risk of stomach cancer. The evidence for this link is strongest in people who have 3 or more drinks per day.

Tobacco use

Smoking increases stomach cancer risk, particularly for cancers of the upper part of the stomach near the esophagus. The risk of stomach cancer is nearly doubled in people who smoke.

Previous stomach surgery

Stomach cancers are more likely to develop in people who have had part of their stomach removed to treat non-cancerous diseases such as ulcers. This might be because the stomach makes less acid, which allows more harmful bacteria to be present. Reflux (backup) of bile from the small intestine into the stomach after surgery might also add to the increased risk. These cancers typically develop many years after the surgery.

Some types of stomach polyps

Polyps are growths on the inner lining of the stomach. Most types of polyps (such as hyperplastic polyps or inflammatory polyps) do not seem to increase a person’s risk of stomach cancer. But adenomatous polyps, also called adenomas, can sometimes develop into cancer.

Pernicious anemia

Certain cells in the stomach lining normally make a substance called intrinsic factor (IF) that the body needs to absorb vitamin B12 from foods. People without enough IF may end up with a vitamin B12 deficiency, which affects the body’s ability to make new red blood cells and can cause other problems as well. This condition, called pernicious anemia, can be caused by certain autoimmune conditions, as well as by some types of stomach surgery.

Along with anemia (having too few red blood cells), people with this disease have an increased risk of stomach cancer.

Menetrier disease (hypertrophic gastropathy)

In this condition, excess growth of the stomach's inner lining causes large folds in the lining and leads to low levels of stomach acid. Because this disease is very rare, it is not known exactly how much it increases the risk of stomach cancer.

Inherited cancer syndromes

Some people inherit gene mutations (changes) from their parents that lead to conditions that can raise their risk of stomach cancer. These inherited syndromes account for only a small percentage of stomach cancers worldwide.

A family history of stomach cancer

People with first-degree relatives (parents, siblings, or children) who have had stomach cancer are more likely to develop this disease, even if they don’t have 1 of the inherited cancer syndromes described above. Still, most people who get stomach cancer don’t have a family history of it.

Common variable immune deficiency (CVID)

In people with CVID, the immune system can’t make enough antibodies to help protect against germs. This can lead to frequent infections as well as other problems, including atrophic gastritis and pernicious anemia. People with CVID are more likely to get gastric lymphoma and stomach cancer.

Certain occupations

Workers in the coal, metal, and rubber industries seem to have a higher risk of stomach cancer.

Having type A blood

Blood type groups refer to certain substances that are normally on the surface of red blood cells and some other types of cells. These groups are important in matching blood for transfusions. For unclear reasons, people with type A blood have a higher risk of stomach cancer.

Epstein-Barr virus (EBV) infection

Epstein-Barr virus causes infectious mononucleosis (also called mono). Most people are infected with this virus at some time in their lives, usually as children or teens.

EBV has been linked to nasopharyngeal cancer and to some forms of lymphoma. It is also found in the cancer cells of about 5% to 10% of people with stomach cancer, although it isn’t yet clear how the virus might cause stomach cancer. Stomach cancers linked to EBV tend to grow more slowly and have less tendency to spread.