Common Stomach Bug May Increase Alzheimer’s Risk

February 7, 2024

A gut bacteria that causes ulcers may be linked to an increased risk of developing Alzheimer’s disease. The bacteria, known as Helicobacter pylori, or H. pylori, is present in 30 to 40 percent of Americans, and in more than half of people worldwide.

Most people infected with H. pylori don’t even know they have it. But about 10 percent of those with the stomach bacteria go on to develop a peptic ulcer, a sore in the lining of the stomach or small intestine. The most common sign of an ulcer is a dull ache or burning in the belly, which may come and go or worsen when the stomach is empty. Other symptoms include frequent burping or bloating, nausea, or black or tarry stools. Left untreated, long-term infection with H. pylori may eventually lead to stomach cancer.

Earlier research had suggested a possible link between H. pylori and dementia risk. To investigate further, scientists at McGill University in Montreal and Charite University in Berlin analyzed medical records of more than four million men and women aged 50 and older living in Britain. They found that people with symptomatic H. pylori infection had an 11 percent higher risk of developing Alzheimer’s disease, the most common form of dementia. The risk was greatest about 10 years after the onset of symptoms.

“This finding reinforces the assumption that an H. pylori infection could be a modifiable risk factor for Alzheimer’s disease,” said Antonios Douros, a pharmacoepidemiologist at Charité and the study’s first author. “We know that the bacterium can reach the brain via various routes, potentially causing inflammation, damage and the destruction of neurons there,” When the stomach has been damaged by these microbes, it is also less able to absorb vitamin B12 or iron effectively, which can also increase the risk of dementia.

If you’re concerned about H. pylori infection or think you may have an ulcer, talk to your doctor. Breath tests and stool tests are available to detect the bacteria. Follow-up tests using scopes in the stomach may also be necessary to confirm the diagnosis.

If H. pylori is present, you can be treated with a course of antibiotics. Other drugs like PPIs (proton pump inhibitors) that reduce levels of acid in the stomach are also given to allow the stomach’s lining to heal.

“We hope the findings from this investigation will provide insight on the potential role of H. pylori in dementia in order to inform the development of prevention strategies, such as individualized eradication programs, to reduce infections at the population level,” said Dr. Paul Brassard, the study’s senior author and a professor at McGill. Further research is needed to determine how treatment for H. pylori might affect Alzheimer’s risk. The study was published in the journal Alzheimer’s and Dementia.

By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Eric Schmidt, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University. 

Source: Antonios Douros, Zharmain Ante, Carlo A. Fallone, et al: “Clinically apparent Helicobacter pylori infection and the risk of incident Alzheimer’s disease: A population-based nested case-control study.” Alzheimer’s and Dementia: The Journal of the Alzheimer’s Association, Dec. 13, 2023


Alzheimer's Articles