• Posted January 23, 2025

Controlling Infections Might Lower Dementia Risk

Preventing or treating infections could be a key means of warding off dementia, a new evidence review says.

Vaccines, antibiotics, antiviral medications and anti-inflammatory drugs are all associated with a reduced risk of dementia, researchers reported in a study published Jan. 21 in the journal Alzheimer’s and Dementia: Translational Research & Clinical Interventions.

These results support the notion that common dementias might be triggered by infections.

“Viral and bacterial infectious causes of common dementias have been proposed, supported by epidemiological data linking infection to dementia risk,” wrote the research team led by Dr. Benjamin Underwood, an assistant professor of psychiatry at the University of Cambridge.

“Antiviral drugs have been identified as some of the most promising repurposed drugs for dementia, and there is increasing interest in vaccination as being generally protective,” the researchers added.

For their review, researchers examined 14 studies involving more than 130 million people and 1 million cases of dementia, to see if any existing drugs could be repurposed to help treat dementia.

“We urgently need new treatments to slow the progress of dementia, if not to prevent it,” Underwood said. “If we can find drugs that are already licensed for other conditions, then we can get them into trials and -- crucially -- may be able to make them available to patients much, much faster than we could do for an entirely new drug.”

The team found conflicting evidence regarding several classes of drugs like blood pressure meds, antidepressants and diabetes medication. Some studies associated these drugs with a lower risk of dementia, while others showed a higher risk.

But the pooled evidence revealed an unexpected association between a reduced risk of dementia and the use of antibiotics, antivirals and vaccines, researchers said.

Anti-inflammatory drugs like ibuprofen also appeared to lower risk of dementia, researchers said.

“Inflammation is increasingly being seen to be a significant contributor to a wide range of diseases, and its role in dementia is supported by the fact that some genes that increase the risk of dementia are part of inflammatory pathways,” researchers said in a news release.

However, they noted that these studies can’t prove a true cause-and-effect link between these drugs and dementia.

“Because a particular drug is associated with an altered risk of dementia, it doesn’t necessarily mean that it causes or indeed helps in dementia,” researcher Illianna Lourida, a research fellow with the University of Exeter, said in a news release.

“We know that diabetes increases your risk of dementia, for example, so anyone on medication to manage their glucose levels would naturally also be at a higher risk of dementia – but that doesn’t mean the drug increases your risk,” she said.

Lourida said it's important to keep in mind that all drugs have benefits and risks.

“You should never change your medicine without discussing this first with your doctor, and you should speak to them if you have any concerns,” she said.

More research is needed both to prove the effectiveness of these drugs against dementia and to find more drugs that can help, researchers concluded.

More information

The Alzheimer’s Society has more about infections and dementia risk.

SOURCE: University of Cambridge, news release, Jan. 21, 2025