Helicobacter infection has been linked to an increased risk of Alzheimer's disease

Clinically significant Helicobacter pylori infection is associated with a long-term risk of developing Alzheimer's disease, with an average risk increase of 11 percent. This conclusion was reached by Canadian scientists who analyzed a cohort of more than four million people. The findings are published in Alzheimer's & Dementia.

It is believed that approximately 40 million people worldwide suffer from Alzheimer's disease. Various risk factors for the development of this form of dementia are known, among which various infections are increasingly being identified in studies. Several studies have shown that, in general, any infection in old age increases the risk of developing the disease. Other work has documented the contribution of herpes infection to the development of dementia.

In recent years, however, numerous preclinical, serologic, and postmortem studies have shown that Helicobacter pylori, which is responsible for gastric and duodenal ulcers, gastritis, duodenitis, and gastric cancer, may play an important role in the development of Alzheimer's disease. However, so far, due to the small amount of data, it is difficult to speak about the importance of infection in the development of the disease.

Paul Brassard and colleagues at McGill University conducted a population-based study that examined the relationship between Helicobacter infection and the development of Alzheimer's disease. To do this, the researchers followed a cohort of 4262092 people without dementia over the age of 50 (mean age 60.4 years) who were followed for an average of 11 years. During this time, 40455 cases of Alzheimer's disease were recorded.

Clinically significant Helicobacter infection was associated with a moderately increased risk of developing Alzheimer's disease: on average, the risk increased by 11 percent. The highest risk, 24 percent, was observed 7.3 to 10.8 years after the onset of infection. However, the scientists found no significant effect of age and gender on this risk.

In the future, scientists will have to figure out the mechanisms of this link. So far, they suggest that potentially this relationship may be affected by disorders of the intestinal microbiome and absorption of vitamin B12 and iron.

If there is a link between Helicobacter infection and Alzheimer's disease, then prevention of infection would also be a prevention of dementia. However, the number of patients with Helicobacter pylori, in general, is steadily decreasing: the global prevalence of infection has decreased by 15 percent over 30 years.