Science News

Common Bacterium Related to Parkinson’s Disease

- Apr 05 2012

A common bacterial infection may contribute to Parkinson’s disease (PD) risk, according to new research published in the European Journal of Neurology. The study is the first to link the bacterium to Parkinson’s in a large population.

The bacterium, called Helicobacter pylori (HP), is more commonly associated with stomach problems, including ulcers and rarely, stomach cancer. But researchers have long been puzzled as to why many people with Parkinson’s have a history of stomach problems, such as ulcers, prior to developing Parkinson’s. Some research has even shown that eliminating H. pylori infections helped with the symptoms of Parkinson’s. Yet no researchers had done an epidemiological study in a large group in order to statistically link H. pylori to Parkinson’s.

A new study, performed by a group led by Beate Ritz, M.D., Ph.D., used two large Danish databases, one full of information regarding drug prescriptions and one of medical records. For every person with Parkinson’s identified, Dr. Ritz and colleagues randomly selected five controls without Parkinson’s, of the same sex and age. They then looked for a connection between the prescription of drugs that treat H. pylori and the eventual clinical diagnosis of Parkinson’s five years later.

Results

Out of 3,489 people who eventually developed Parkinson’s, 138 of them, or 3.9 percent, had been treated for H. pylori. In the control group, 2.9 percent had been treated for H. pylori.
The study revealed a 46 percent increase in the likelihood of developing Parkinson’s if the person had been treated for H. pylori at least five years prior.

What Does It Mean?

The possibility of a link between stomach problems and Parkinson’s has intrigued researchers for some time. In this study, epidemiologists showed, for the first time, that people who had been treated for H. pylori had a higher risk of developing Parkinson’s. If this link is confirmed with biological studies, it suggests that rapid treatment of H. pylori infection could prevent the development of Parkinson’s later. It should be noted that PD incidence was higher in the group that was treated for H. pylori only by one percent (2.9 percent in the control group to 3.9 percent in the group treated for H. pylori).

This study has some limitations. First, because it was performed using medical records and prescription drug records, it is impossible to know the accuracy of the diagnoses of H. pylori infection and Parkinson’s. Furthermore, because the study inferred H. pylori infection status based on drug prescriptions, it could be that drug prescriptions were written not only for H. pylori infections but also for off-label uses, or that H. pylori infections were not always present when drugs were prescribed. Most importantly, this type of study cannot determine whether early Parkinson’s makes H. pylori infection more likely, or whether H. pylori infection leads to Parkinson’s development. However, identifying a potentially treatable risk for Parkinson’s is important and merits additional research. Further biological research that attempts to uncover a mechanism linking HP to PD will be needed to answer these questions.

Reference: Nielsen, H.H., Qiu, J., Frils, S., Wemuth, L., Ritz, B. (2012). Treatment for Helicobacter pylori infection and risk of parkinson’s disease in Denmark. European Journal of Neurology, published ahead of print January 17, 2012, doi 10.1111/j.1468-1331.2011.03643.x.

Source Date: Apr 05 2012