The short answer
Long-term infection with H. pylori bacteria is a major risk factor for stomach cancer. Smoking, diets high in salted, smoked, or poorly preserved foods, older age, being male, and family history also raise risk.
Long-term H. pylori bacterial infection is a major risk factor.
Smoking raises the risk of stomach cancer.
Diets high in salted, smoked, or poorly preserved foods, or low in fruits and vegetables, are linked to higher risk.
Older age, being male, and family history raise risk.
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The whole article, with every detail and caution.
This page is for anyone who wants to know what raises the chance of stomach cancer. It covers the main risk factors, which ones can be changed, and questions to ask your care team.
The simple version
A risk factor is anything that raises the chance of a disease. It does not mean you will get that disease. For stomach cancer, long-term infection of the stomach lining with a bacterium called H. pylori is a major risk factor, according to NCI.
H. pylori infection
NCI lists chronic infection of the stomach lining with H. pylori as a major risk factor for stomach cancer. If you have ongoing stomach symptoms, ask your doctor whether H. pylori testing makes sense for you.
Long-term H. pylori infection is a major risk factor for stomach cancer.
Diet and lifestyle
NCI says a diet low in fruits and vegetables, or high in salted, smoked, or poorly preserved foods, raises risk. People who smoke have a higher risk of stomach cancer than people who do not.
Who else is at higher risk
Risk goes up as a person gets older. Males are nearly twice as likely as females to be diagnosed. Having a parent, sibling, or child who has had stomach cancer raises risk. Some stomach conditions raise risk as well, including chronic atrophic gastritis (long-lasting stomach inflammation) and pernicious anemia (a condition in which the body cannot absorb enough vitamin B12).
Having a risk factor is not a diagnosis
Most people with one or more of these risk factors never get stomach cancer. Risk factors describe a pattern seen across large groups of people, not a prediction for any one person. Still, knowing your own risk factors helps you and your doctor decide whether testing makes sense, especially if you also have ongoing symptoms.
Changing what you can
You cannot change your age, sex, or family history. Smoking and diet are within your control. Ask your doctor about quitting smoking if you smoke, and about H. pylori testing if you have ongoing stomach symptoms.
A few more factors to know
NCI also lists type A blood, Epstein-Barr virus infection, obesity (excess body weight), gastroesophageal reflux disease (GERD), and working in the rubber or coal industry or being exposed to very high levels of radiation.
What to ask your team
- Should I be tested for H. pylori infection?
- Does my family or personal history put me at higher risk?
- If I have an infection, what should we do about it?
- What symptoms should prompt me to come back for a checkup?
Sources
Common questions
What is the biggest risk factor?
Long-term infection of the stomach lining with H. pylori, a stomach bacterium, is a major risk factor, according to NCI.
What dietary factors matter?
Diets high in salted, smoked, or poorly preserved foods, and diets low in fruits and vegetables, are linked to higher stomach cancer risk.
Who else is at higher risk?
Risk rises with age, and men are nearly twice as likely as women to be diagnosed. Smoking, a family history of stomach cancer, and certain stomach conditions also raise risk.
Can risk be lowered?
Some risk factors, such as smoking and diet, can be changed. Ask your care team whether H. pylori testing makes sense for you.
Questions to ask your doctor
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Last updated: 2026-10-16Next planned review: 2027-07-07
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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