Stomach cancer is primarily caused by chronic inflammation of the stomach lining, with Helicobacter pylori (H. pylori) bacterial infection being the leading cause. Other major risk factors include a diet high in smoked, pickled, or salted foods, smoking, alcohol consumption, obesity, and long-term conditions like gastritis or stomach polyps.

Key Causes and Risk Factors for Stomach Cancer

Infection: H. pylori bacteria is a major contributor, causing long-term, often silent, infection that leads to inflammation (gastritis) and, over time, potential cancer development.

Dietary Factors: A diet high in salt-preserved foods (smoked, pickled, salted) and low in fresh fruits and vegetables significantly increases risk.

Lifestyle Choices: Tobacco smoking and excessive alcohol consumption are directly linked to higher stomach cancer incidence.

Chronic Stomach Conditions: Long-term inflammation (chronic gastritis), pernicious anemia (low red blood cells), and gastric polyps (non-cancerous growths) can precede the development of cancer.

Genetics and Family History: A family history of stomach cancer or inheriting genetic conditions (e.g., Lynch syndrome, hereditary diffuse gastric cancer) increases risk.

Age and Gender: The risk increases with age, with most cases occurring in people over 60.

Previous Surgery: A partial gastrectomy (removal of part of the stomach) to treat non-cancerous conditions can increase risk over time.

While these factors are strongly associated with stomach cancer, it can still occur without them, and having these risk factors does not mean one will develop the disease.