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Helicobacter pylori bacterial infection triggers inflammatory reactions
Helicobacter pylori bacterial infection triggers a series of inflammatory reactions that are considered an important cause of chronic gastritis . both genetic and environmental risk factors . Its risk factors differ depending on whether cancers arise in the proximal ( central ) or in the distal ( away from the centre ) region . Advanced age , male sex , smoking , and family history are common risk factors for both proximal and distal cancers . In terms of race and ethnicity , whites tend to develop cardia cancer in the area between the oesophagus and stomach , whereas Hispanics and Asians tend to develop distal cancer . Helicobacter pylori infection , from a bacteria found in the stomach , and dietary factors , such as high intake of salt , increase the risk of distal cancer . On the other hand , obesity and �E�D , or gastroesophageal reflux disease from stomach acid , are mainly associated with cancers arising from the proximal region .
The incidence of gastric cancer increases with age . Approximately 70 percent of cases were diagnosed in individuals aged 55 to 84 . Compared with women , men have a higher risk of both proximal and distal gastric cancer . The reason is unclear , but environmental or occupational exposures may play a role . Men have historically tended to smoke more than women , whereas oestrogens may protect against the development of gastric cancer . Delayed menopause and increased fertility may lower the risk of gastric cancer .
There is significant variability in the gastric cancer incidence among races . The incidence of gastric cancer among whites is approximately half that of
Asians and Pacific Islanders , African Americans , and Hispanics for both men and women . Among Asian American subgroups , Korean and Japanese Americans have an especially high incidence rate . In a study evaluating the effect of immigration on the incidence of gastric cancer among Japanese in Hawaii , first-generation participants had high rates of gastric cancer ; however , after two generations , gastric cancer rates among Japanese Americans had decreased to a level that was similar to those of Americans of European ancestry .
Helicobacter pylori bacterial infection triggers a series of inflammatory reactions that are considered an important cause of chronic gastritis . Progression from chronic gastritis to gastric atrophy and IM is an early step of mucosal changes in the stomach , leading to dysplasia and ultimately cancer . H pylori has been classified as a World Health Organization Class I carcinogen since 1994 because several studies have demonstrated an association between H pylori infection and development of gastric cancer , which develops in approximately one percent of H pylori – infected subjects ; conversely , more than 90 percent of patients with gastric cancer have had current or past H pylori infection .
Hereditary diffuse gastric cancer is a rare genetic syndrome characterised by the early onset ( i . e ., before age 40 ) of diffuse gastric adenocarcinoma from glandular cells , an increased risk of lobular breast cancer that begins in the milk producing glands , signet-ring cell colorectal cancer , and a poor prognosis . Gastric cancer risk is also increased in patients with Lynch syndrome , with affected individuals carrying a 10 percent lifetime risk . Other hereditary syndromes , such as hereditary breast and ovarian cancer , are also associated with an increased risk for gastric cancer . Atrophic gastritis and intestinal metaplasia AG and IM are considered precursor conditions of gastric cancer , and both are strongly associated with H pylori infection .
Other factors such as cigarette smoking , alcohol , obesity , low fruit and vegetable consumption , and high salt intake appear to be modest compared with the other risk factors discussed .
Screening can be performed in the general population ( mass screening ) or only for individuals with an increased risk for developing gastric cancer . Although the effectiveness of mass screening still remains controversial , it ’ s been undertaken in Korea and Japan where there ’ s a high incidence of the disease . But in countries with a low incidence of gastric cancer , such as the United States , mass screening would not be cost effective , and only individuals at high risk should be considered for screening .
Abundant evidence shows that H pylori infection , family history of gastric cancer , and atrophic gastritis / intestinal metaplasia are associated with an increased risk asdf of gastric cancer , and therefore individuals with these risk factors could be considered high risk .
64 AUGUST 2021 GlobalHealthAndTravel . com