Infection-related hospitalizations are associated with a higher risk of developing dementia

Infection-related hospitalizations are associated with a higher risk of developing dementia

A new research paper was published in Volume 17, Issue 10 ofAging-USAon October 13, 2025, entitled “Hospitalization with infections and dementia risk: a systematic review and meta-analysis.”

This large-scale meta-analysis led by first author Wei Yu Chua of the National University of Singapore and corresponding author Eng-King Tan of the National Neuroscience Institute and Duke-NUS Medical School in Singapore shows that adults hospitalized with infections have a significantly higher risk of developing dementia. The findings are particularly important as the world's population ages and hospitalizations due to infections increase, highlighting a potential new approach to dementia prevention.

“Of 1900 studies that were initially screened, 16 studies with 4,266,276 patients were included in the analysis.”

Researchers analyzed data from over 4 million people across 16 studies. This makes this study the most comprehensive review to date of the relationship between infection-related hospitalizations and long-term brain health. The results showed that hospitalization for an infection increased the risk of all-cause dementia by 83%. Among the types of infections examined, sepsis posed the highest risk, followed by pneumonia, urinary tract infections, and skin or soft tissue infections. The risk of developing vascular dementia was significantly higher than that of Alzheimer's disease.

One possible explanation for the connection between infections and dementia is that infections trigger systemic inflammation that can reach the brain. Inflammatory molecules can cross the blood-brain barrier, potentially leading to the formation of harmful proteins and the death of brain cells. This process can be more serious in older adults because their immune systems are often slower to respond and recover. The study also suggests that even a single infection-related hospitalization can accelerate cognitive decline, especially in people who are already at higher risk.

Importantly, the risk of dementia was greatest in the first year after infection, but remained elevated for many years afterwards. In fact, studies with more than a decade of follow-up showed even stronger associations. These results suggest the need for early cognitive monitoring after hospital discharge, particularly in older adults recovering from infections.

These findings have important implications for healthcare systems, particularly those serving aging populations, and highlight the lasting impact that infections can have on the brain. This research highlights the importance of looking beyond genetics and lifestyle when it comes to prevention strategies. With dementia affecting over 50 million people worldwide and annual care costs in the United States exceeding $300 billion, identifying new and preventable risk factors is critical. Reducing infections, improving hospital care, and monitoring brain health after illness could offer promising opportunities to protect cognitive function in aging populations.

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