Bug Named Suspect in Cause of Type 2 Diabetes

March 19th, 2012

written by Michael O'Leary

Thirty years ago a tiny corkscrew-shaped bug that is commonly found in people’s stomachs was positively identified as the culprit in 70 percent to 90 percent of peptic ulcers.

Since then the rap sheet on this bug has grown. Not only are ulcers caused by H. Pylori, it has also been linked to an increased risk of stomach cancer, stomach lymphoma, iron deficiency anemia and unexplained low platelet counts. (Published site)



Now researchers have drawn a link via a population study between this same bug and type 2 diabetes, and an even stronger link between a particular strain of the bug and the disease.
The bug is Helicobacter pylori, or H. pylori for short. The findings were published online today ahead of April 15 publication in the Journal of Infectious Diseases. The study involved surveys of two groups of people as part of a long ongoing series of national surveys, called the National Health and Nutrition Examination Surveys conducted by the National Center for Health Statistics. The first such survey was done in 1971 and the purpose is to identify the prevalence of and risk factors for diseases.

As reported by MedPage Today, the two surveys that found the link between Type 2 diabetes involved 7,417 people 18 or older surveyed in the NHANES III survey and 6,072 people age 3 and older surveyed in 1990-2000. These were the only two surveys in the series that collected information on H. pylori and HbA1c.

At first they found no association between the bug and participants who reported that they had type 2 diabetes. When they excluded people with a history of diabetes and made adjustments for other factors, however, they found that people with a particular strain of H. pylori that has a gene called cagA more likely to have elevated HbA1c levels
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The link was most apparent in the group surveyed between 1990 and 2000. In the 2,403 participants who were positive for H. pylori their average HbA1c levels were at 5.49 percent. Among the 3,669 who were negative for H. pylori their average HbA1c  levels were 5.40 percent. While that may seem like a small difference, in statistical terms, the researchers calculated that the probability that the difference was due to chance was 2 percent.

Similarly, in the NHANES III group the difference in HbA1c levels between those positive for H. pylori and those without was not significant. When they excluded diabetics taking insulin, however, the difference became significant.

If this link is confirmed in more studies, Dr. Dani Cohen, of Tel Aviv University in Israel and Dr. Khitam Muhsen, of the University of Maryland said in an editorial about this study that it could have important clinical and public health implications.