Most people don’t spend much time thinking about stomach cancer—until it affects them or someone they love. But with one million new cases diagnosed worldwide each year, this disease is far from rare. It’s the fifth most common type of cancer and the fourth leading cause of cancer-related deaths, yet it often goes undetected until it reaches advanced stages.

Unlike some cancers with clear warning signs, stomach cancer often develops quietly, with early symptoms that can be mistaken for digestive discomfort. Because of this, many cases aren’t detected until later stages, making early awareness critical.

Researchers have identified several key risk factors that contribute to stomach cancer. Some are tied to lifestyle choices, while others are linked to genetics, infections, or environmental exposures. Understanding these causes can help with prevention, early detection, and informed healthcare decisions.

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1.

Helicobacter pylori Infection

Helicobacter pylori (H. pylori) is a spiral-shaped bacterium that lives in the stomach lining. To survive, it neutralizes stomach acid in its immediate surroundings, allowing it to burrow into the protective mucus layer, where it avoids the immune system.

Many people carry H. pylori without symptoms, but in some cases, it triggers chronic inflammation, increasing the risk of stomach cancer. Research shows that eliminating H. pylori with antibiotics can reduce cancer risk, but reinfection is possible.

Illustration of a stomach highlighting the presence of Helicobacter pylori bacteria, a known risk factor for stomach cancer

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2.

Diet and Food Preservation Methods

Studies show that high salt intake, especially when combined with an H. pylori infection, may increase cancer risk. Other dietary factors include:

  • Smoked foods—Consumption can triple stomach cancer risk.
  • Pickled foods—Some studies suggest a 50% increased risk.
  • Alcohol & Processed Meats—Both have been linked to a higher incidence of stomach cancer.

On the other hand, some foods may have a protective effect:

  • Citrus fruits
  • Cruciferous vegetables (broccoli, cauliflower, Brussels sprouts)
  • The Mediterranean diet, rich in vegetables, legumes, and fish

Making dietary adjustments may help lower the risk of stomach cancer over time.

Close-up of a person holding a salt shaker, highlighting the link between high salt intake and an increased risk of stomach cancer

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3.

Smoking

Smoking is a major risk factor for stomach cancer, particularly gastric cardia cancer, which occurs where the stomach meets the esophagus.

Research shows that the risk increases with:

  • Longer smoking history
  • Higher cigarette consumption (up to 20 cigarettes per day)

Fortunately, quitting smoking can significantly lower this risk. Studies show that the risk of stomach cancer begins to drop within a few years after quitting and continues to decline over time.

Close-up of a hand taking a cigarette from a pack, emphasizing the link between smoking and an increased risk of stomach cancer

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4.

Alcohol Consumption

Alcohol consumption is a known risk factor for gastrointestinal cancers, including stomach cancer. A meta-analysis of 81 studies found that regular alcohol intake increases stomach cancer risk.

Additionally, research suggests:

Chronic alcohol use irritates the stomach lining, leading to inflammation and cell damage, both of which contribute to cancer development.

Three women holding colorful alcoholic drinks with garnishes, highlighting the association between alcohol consumption and an increased risk of stomach cancer

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5.

Genetics and Family History

A family history of stomach cancer significantly increases risk. While many cases of stomach cancer develop without a hereditary link, some genetic syndromes can make a person more susceptible to the disease. Conditions such as Hereditary Diffuse Gastric Cancer (HDGC), Familial Adenomatous Polyposis (FAP), Li-Fraumeni Syndrome, and Lynch Syndrome are all associated with an increased risk.

If you have a first-degree relative with stomach cancer, consider:

  • Genetic testing to assess inherited risk.
  • Regular screenings for early detection.
  • Proactive lifestyle measures to help reduce risk where possible.

Hands holding an old black-and-white family photo, symbolizing the role of genetic predisposition and hereditary factors in the risk of developing stomach cancer

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6.

Obesity

Obesity is a well-established risk factor for many gastrointestinal cancers, including stomach cancer. Researchers believe excess body fat contributes to cancer development in several ways, particularly through chronic inflammation and metabolic changes.

Obesity can disrupt insulin and growth factor signaling, both of which play a role in cell growth and regulation. It may also alter sex hormone synthesis, further increasing cancer susceptibility.

A green apple and measuring tape on a desk, symbolizing healthy weight management, with a doctor in the background discussing obesity as a potential risk factor for stomach cancer

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7.

Chronic Gastritis and Pernicious Anemia

Long-term inflammation of the stomach lining, known as chronic gastritis, can increase the risk of stomach cancer. While inflammation is a normal immune response, chronic irritation can damage stomach cells and trigger DNA changes, making them more vulnerable to malignancy .

Pernicious anemia, a condition linked to chronic gastritis, occurs when the body fails to absorb enough vitamin B12. Over time, this deficiency can cause further stomach lining damage, increasing cancer risk. Pernicious anemia is often autoimmune-related, meaning the immune system mistakenly attacks stomach cells that produce intrinsic factor, worsening inflammation.

Because both chronic gastritis and pernicious anemia involve stomach lining damage, individuals with these conditions should consult their doctor about regular screenings to monitor for potential cancerous changes.

A creative depiction of a stomach made from white and brown pills on a light blue background, symbolizing medical conditions like pernicious anemia and chronic gastritis, which are associated with an increased risk of stomach cancer

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8.

Gastric Polyps and Previous Stomach Surgery

Structural changes in the stomach—whether from naturally occurring polyps or past surgeries—can contribute to stomach cancer risk.

Gastric polyps are abnormal growths on the stomach lining. While most are harmless, adenomatous polyps have a higher likelihood of becoming cancerous.

Some individuals develop these polyps due to Familial Adenomatous Polyposis (FAP), an inherited condition that significantly raises cancer risk.

Similarly, stomach surgeries, such as partial gastrectomy, may increase cancer risk. Some studies suggest that stomach cancer is more likely to develop in the portion of the stomach left behind after surgery.

For individuals who have undergone gastric bypass surgery, findings are mixed. Some research links bypass procedures to an increased risk of cancer in the excluded portion of the stomach, while other studies have found no significant correlation.

For those with a history of stomach surgery or gastric polyps, doctors may recommend periodic endoscopic screenings to monitor changes in the stomach lining.

A doctor pointing to a detailed anatomical model of a stomach, illustrating medical conditions like gastric polyps and the effects of stomach surgery, both of which can increase the risk of stomach cancer.

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9.

Occupational Exposures

Certain industries expose workers to carcinogenic chemicals, increasing the risk of stomach cancer. Jobs in mining, construction, textiles, farming, dry cleaning, and the food industry may involve frequent exposure to substances such as:

  • Solvents
  • Pesticides & herbicides
  • Asbestos & coal dust
  • Ionizing radiation

Long-term exposure to these chemicals can damage stomach lining cells, contributing to cancer development. Workers in high-risk industries should take protective measures and undergo regular health screenings.

A farming scene at sunset with a combine harvester in a field, highlighting the potential exposure of agricultural workers to carcinogenic chemicals such as pesticides and herbicides, which may increase the risk of stomach cancer.

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10.

Epstein-Barr Virus (EBV)

Epstein-Barr virus (EBV) is best known for causing mononucleosis, but it has also been linked to certain types of cancer, including stomach cancer. EBV-associated gastric cancer accounts for about 9% of stomach cancer cases.

A notebook with ‘EBV - Epstein-Barr Virus’ written on it, placed on a white desk with autumn leaves, a pen, and a small plant, representing the potential link between Epstein-Barr Virus and stomach cancer.

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11.

Age and Gender

Stomach cancer risk increases with age, and in the U.S., men are twice as likely to develop the disease. The majority of cases occur in people over the age of 50, though rates in younger individuals—especially women—have been rising in recent years.

An older man and woman, smiling and looking surprised against a blue background, symbolizing the role of aging and gender as risk factors in the development of stomach cancer.

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12.

When to See a Doctor

Early-stage stomach cancer is often difficult to detect because symptoms can be mild or mistaken for common digestive issues. However, persistent symptoms may indicate a need for further evaluation:

  • Unexplained weight loss
  • Feeling full after eating small amounts
  • Bloating, nausea, or vomiting
  • Black stools, which may indicate internal bleeding

While some risks—such as genetics and age—are unavoidable, lifestyle changes like maintaining a healthy weight, reducing alcohol and tobacco use, and following a balanced diet can help lower the likelihood of developing the disease.

For those with a family history of stomach cancer or other significant risk factors, genetic testing and regular screenings may provide valuable insights for early intervention.

If you have concerns about your personal risk, speaking with a healthcare provider can help you develop a proactive plan for prevention and monitoring.

A close-up of a stomach model on a desk, with a medical form and pen in the foreground. In the background, a doctor examines a patient, emphasizing the importance of prevention and regular screening in detecting and managing stomach cancer.
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