A systematic analysis of data from more than four million patients across Europe, the USA, Asia, and Oceania has revealed that hospitalization due to severe infections, such as sepsis and pneumonia, significantly increases the risk of developing dementia.

The Impact of Severe Infections on Dementia Risk

Each year, neurodegenerative diseases, which are characterized by the gradual death of brain cells, claim the lives of around 1.8 million people. The most common form of dementia is Alzheimer’s disease, which typically progresses in two stages and is most often diagnosed in people over the age of 65.

To determine whether there is a link between hospitalization for severe infections and the development of neurodegenerative diseases, an international research team led by Wei Yui Chua and Eng-King Tan from the National University of Singapore conducted a meta-analysis of 16 studies. The analysis included data from 4,266,276 patients from the UK, USA, Europe, New Zealand, Taiwan, and Finland.

Key Findings of the Study

According to a publication in the journal Aging, the risk of developing any form of dementia was 83% higher among patients who had experienced an infection requiring hospitalization compared to those who had not been hospitalized. The data for specific types of infections were particularly concerning:

• Sepsis increased the risk by 78%
• Pneumonia by 69%
• Urinary tract infections by 57%
• Skin and soft tissue infections by 42%

The risk of vascular dementia in these patients rose nearly 3.7 times, while the risk of Alzheimer’s disease increased 1.6 times. This is likely related to vascular damage and chronic inflammation triggered by infection, which can disrupt the function of the blood-brain barrier. The entry of inflammatory molecules and pathogens into the brain accelerates the formation and accumulation of amyloid and tau proteins, which play a key role in the development of Alzheimer’s disease. In cases of vascular dementia, infections can damage the small blood vessels in the brain.

The Importance of Monitoring and Prevention

Since the consequences of severe infections can be long-lasting, researchers emphasize the need for careful monitoring of cognitive health in patients over 60, especially during the first year after hospitalization, when the risk of cognitive impairment is highest.

The likelihood of developing dementia can be reduced through early cognitive monitoring programs and preventive measures, such as controlling inflammation, maintaining cardiovascular health, and getting vaccinated against respiratory infections.

“We should view infection not only as a temporary illness, but also as a potential factor in accelerated brain aging,” the researchers concluded.