August 16, 2012

African ancestry, stomach bug link

Socioeconomic factors, African ancestry linked to risk for cancer-causing infection.

The gut-dwelling bacterium Helicobacter pylori is a major risk factor for ulcers and gastric cancer. Although the infection rate in the United States is lower than in other parts of the world, Meira Epplein, Ph.D., assistant professor of Medicine, and colleagues previously found a very high prevalence among low-income African-Americans – particularly among those of high African ancestry.

To better understand this trend, Epplein and colleagues investigated the impact of neighborhood-level socio-economic factors on H. pylori prevalence. They report in the June issue of Cancer Causes & Control that three neighborhood-level factors – percent completed high school, median house values, and percent employed – were significantly associated with prevalence of CagA+ H. pylori (highly virulent strains most strongly linked to gastric cancer). However, those with high African ancestry still showed a much higher prevalence even after controlling for these factors.

The findings suggest that while neighborhood-level socioeconomic factors might highlight high-risk areas for prevention and screening strategies, the link between African ancestry and H. pylori infection may have a biological basis.

The research was supported by grants from the National Cancer Institute (CA092447) of the National Institutes of Health and the American Cancer Society.