While across the entire U.S. population the incidence of a certain type of stomach cancer has been declining in the past three decades, among white adults ages 25 to 39, non cardia gastric cancer — or cancer of the lower stomach — has actually increased, according to a new analysis published this week in the Journal of the American Medical Association.
Researchers found that, while from 1977 to 2006, annual incidence of lower stomach cancer dropped from 5.9 per 100,000 to 4.0 among whites, 13.7 to 9.5 among blacks, and 17.8 to 11.7 in other races, when they parsed the data by both ethnicity and age, for all groups other than young whites, cancer rates dropped or remained stable. Among white adults ages 25 to 39, rates increased from 0.27 per 100,000 in 1977 to 0.45 in 2006.
While the incidence of lower stomach cancer remains very low in the young, white adult population, the surprising increase is a cause for concern, the researchers say. The study, led by investigators at the National Cancer Institute, analyzed data representing more than a quarter of the U.S. population across a nearly 30-year span. Of those included in the data set, 83,225 adults developed some form of stomach cancer during the three decades, while 39,003 were diagnosed specifically with lower stomach cancer.
A majority of lower stomach cancers are caused by chronic infection with the bacteria Helicobacter pylori, which can also cause stomach ulcers. Lower stomach cancer has also been associated with poor diet — particularly high-salt diets, or those rich in foods preserved with salt, the Associated Press reports.
As the AP reports, globally, stomach cancers are the fourth most common form of cancer, and a leading form of cancer among certain groups in the U.S.:
In U.S. men, stomach cancer is among the top 10 most common cancers in blacks, Asian-Americans, Hispanics and American Indians. It’s also among the most common cancers in Asian-American women.
Declines in lower stomach cancer in the U.S. and worldwide have been attributed to improvements in hygiene and food preservation, which decrease the risk for H. pylori infection, the AP reports. The study authors say a next step in the research is to examine what is driving the increase in lower stomach cancer among young, white Americans — and whether the increase in high-salt diets in this age group may play a role.