## Risk Factors and Protective Factors in Gastric Carcinoma ### Established Risk Factors **Key Point:** Gastric carcinoma arises through a well-characterized sequence of mucosal changes, and multiple environmental and infectious factors increase risk. | Risk Factor | Mechanism | Evidence | |---|---|---| | *Helicobacter pylori* (CagA+) | Chronic inflammation, CagA protein translocation, IL-8 upregulation | Strong epidemiologic link; ~3–6× increased risk | | Intestinal metaplasia | Precancerous lesion; represents loss of normal gastric mucosa | Part of Correa cascade; increases dysplasia risk | | Chronic atrophic gastritis | Loss of parietal cells, achlorhydria, bacterial overgrowth | Precancerous condition; facilitates H. pylori colonization | | Smoking | Carcinogen exposure; impairs mucosal healing | Dose-dependent risk increase | | Alcohol (heavy use) | Direct mucosal injury; impaired regeneration | Modest independent risk | | High salt diet | Direct mucosal injury; enhances H. pylori virulence | Epidemiologic association in high-incidence regions | | Obesity | Metabolic and inflammatory changes | Modest increase in risk | | Family history / hereditary diffuse gastric cancer (CDH1 mutation) | Genetic predisposition | Rare but important | ### Protective Factors **High-Yield:** Fresh fruits and vegetables (high in vitamin C and antioxidants) are **protective** against gastric cancer, not risk factors. Vitamin C inhibits N-nitroso compound formation and has antioxidant properties. ### The Correa Cascade Normal mucosa → Chronic gastritis → Atrophic gastritis → Intestinal metaplasia → Dysplasia → Carcinoma This sequence typically spans 10–20 years and is reversible in early stages if H. pylori is eradicated. **Clinical Pearl:** H. pylori eradication in patients with intestinal metaplasia or dysplasia may halt progression and reduce gastric cancer incidence by ~30–40% in endemic populations. **Warning:** Do not confuse protective dietary factors (fruits, vegetables, vitamin C) with risk factors. High dietary salt and processed meat are risk factors; fresh produce is protective.
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