The bacterium Helicobacter pylori is a feared pathogen of the gastrointestinal tract. The widespread pathogen is considered the main cause of stomach ulcers and stomach cancer. And as researchers now report, the stomach germ could increase the risk of Alzheimer’s.
The results of a study by Charité – Universitätsmedizin Berlin and McGill University (Canada), published in the specialist journal Alzheimer’s & Dementia, suggest that an infection with the stomach germ Helicobacter pylori could increase the risk of developing Alzheimer’s dementia.
Eliminate risk factors
As stated in a statement from the Charité – Universitätsmedizin Berlin, dementia will continue to increase in an aging population: In the next 40 years, the frequency of dementia is expected to triple.
Since there is currently no cure in sight, attempts are being made to identify the risk factors for dementia – in the hope of being able to eliminate them.
About a third of people are infected
Research has long focused on the stomach germ Helicobacter pylori (Hp) as a possible risk factor. Around a third of all people in this country are infected with this bacterium.
An infection can have no symptoms, but can also cause inflammation of the stomach lining and even gastric cancer.
Numerous laboratory studies have also found a connection between an Hp infection and the central nervous system.
“We know that the bacterium can reach the brain via various routes and, under certain circumstances, can lead to inflammation, damage and the deterioration of nerve cells,” explains Prof. Antonios Douros, pharmacoepidemiologist at the Charité and lead author of the study.
In addition, a stomach damaged by the germ can no longer absorb vitamin B12 and iron well, which also increases the risk of dementia.
However, many of the previous studies on the connection between Helicobacter pylori infection and Alzheimer’s had methodological weaknesses – for example because the number of people included in the study was too small.
This also means that it has not yet been possible to say exactly how strong the connection is between an infection with Hp and Alzheimer’s dementia.
Study with more than four million people
To iron out these weaknesses is Dr. Antonios Douros, Heisenberg Professor at the Institute for Clinical Pharmacology and Toxicology at the Charité together with Prof. Dr. Paul Brassard, Associate Professor at the Faculty of Medicine and Health Sciences at McGill University in Montreal (Canada) and her colleagues have now succeeded.
In their study with over four million people, not only a large number of people but also the time interval between an HP infection and a possible increase in the risk of Alzheimer’s were taken into account.
Using representative data from electronic patient records from Great Britain, the researchers were able to quantify the connection between the stomach germ Helicobacter pylori and Alzheimer’s dementia over the course of a person’s life.
Not all infected people will inevitably become ill
“Our study shows that symptomatic infections with Helicobacter pylori after the age of 50 can be associated with an eleven percent increased risk of Alzheimer’s dementia. The risk increase reaches its maximum value of 24 percent about a decade after the HP infection,” summarizes Dr. Douros the results together.
However, this does not mean that every person will inevitably develop Alzheimer’s after a symptomatic Hp infection.
The calculations involve an increase in the relative risk compared to people who did not have a symptomatic Hp infection after the age of 50.
Controllable risk factor
So are HP infections a risk factor that can be influenced? “For us, this result reinforces the assumption that a Helicobacter pylori infection could be a modifiable risk factor for Alzheimer’s dementia,” concludes Dr. Douros.
However, whether and to what extent the consistent, comprehensive fight against this stomach germ through so-called eradication programs actually influences the development of Alzheimer’s disease must first be tested in large-scale randomized studies. (ad)