Peptic Ulcers - Complications

The process most likely starts during childhood. Infection with H. pylori in early years promotes a precancerous condition called atrophic gastritis. This may lead to cancer through the following steps:

With atrophic gastritis, the stomach becomes chronically inflamed and loses patches of glands that secrete protein and acid.
Acid protects against carcinogens (substances that cause cancerous changes in cells).
New cells replace those destroyed, but these new cells do not produce enough acid to protect against carcinogens.
Over time, then, cancer cells in the stomach may develop and proliferate.

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Onset of H. pylori infection in adulthood poses an even lower risk, since the development of atrophic gastritis takes years and the patient is likely to die of other causes first. Other factors, such as specific genetic strains and diets might also influence a higher risk for stomach cancer. For instance diets high in salt and low in fresh fruits and vegetables have been associated with a greater risk. Some but not all evidence suggests that the virulent H. pylori genetic strain called CagA may also be a particular risk factor for precancerous changes.

(Interestingly, people with duodenal ulcers caused by H. pylori appear to have a lower risk of stomach cancer, though scientists do not know why. It may be that different H. pylori strains affect the duodenum and the stomach. Or, the high levels of acid that affect the duodenum may help prevent the spread of the bacteria to critical areas of the stomach.)

Pancreatic Cancer. H. pylori has recently been linked to pancreatic cancer.

Heart Disease. Some research has reported a very high rate of H. pylori infection in men with coronary artery disease, but more recent work has found no relationship between the bacteria and heart disease. A 2001 study suggested that only relationship between the bacteria and heart disease may be that people with both tend to be in lower socioeconomic groups. Further studies are needed.

Other Diseases. H. pylori has also been weakly associated with other non-intestinal disorders including migraine, Raynaud's disease (marked by cold extremities), and some skin disorders, such as chronic hives.