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The exact causes of cancer of the stomach aren’t fully understood. It's thought that most adenocarcinoma stomach cancers develop as a result of a combination of risk factors.
Factors that can affect the risk of developing stomach cancer include gender, age, infection, diet, body weight some medical conditions and family history.
Stomach cancer is not infectious and can’t be passed from one person to another.
Stomach cancer is more common in men than in women.
The risk of developing stomach cancer increases as we get older: 95 out of every 100 people (95%) who develop stomach cancer are over 50 years old.
Having H pylori infection in the stomach over a long period of time can increase the risk of stomach cancer.
Eating a diet high in salt, pickled foods and processed meats, such as sausages and bacon, can increase the risk of developing stomach cancer.
During the past 30 years, the number of people who have developed stomach cancer in the UK has fallen. This is probably related to changes in diet, particularly the use of refrigeration, which has led to eating more fresh food and less smoked and pickled food.
Smoking increases the risk of stomach cancer. The longer a person smokes for and the more cigarettes they smoke, the greater the risk.
Studies show that people who are overweight have an increased risk of developing stomach cancer.
Conditions such as long-term acid reflux can increase the risk. In this condition, acid from the stomach affects the gullet or the area where the gullet joins the stomach (the gastro-oesophageal junction).
Conditions that cause lower than normal levels of acid in the stomach – Atrophic gastritis or some types of stomach surgery can increase the risk.
Pernicious anaemia, which is linked to changes in the lining of the stomach, can slightly increase your risk.
Having a brother, sister or parent with stomach cancer can increase your risk. This may be because close family members are likely to share some risk factors for stomach cancer, such as eating a similar diet or having H pylori infection. But shared genes may also play a small part.
In a very small number of families, genes may play a greater part in increasing cancer risk. This is more likely when two or more people on one side of the family are affected, especially if the cancer develops at a younger age (under 50). In these families, there may be a faulty gene that increases the risk of getting stomach cancer.
Content last reviewed: 1 June 2011
Next planned review: 2013
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