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• Posted July 20, 2023

Link Seen Between Inflammation, Alzheimer's

Researchers around the world are working to tease out the mechanisms behind Alzheimer's disease and other forms of dementia. Now, a new study points to so-called systemic inflammation.

British researchers found that inflammation -- activation of the body's innate immune system -- is associated with a small but statistically significant later risk of dementia. They reported their findings July 19 in the journal PLOS ONE.

“In this study, we found associations between higher systemic inflammation levels and risk of being diagnosed with dementia three to 11 years later, although the increase in risk is small,” said study author Krisztina Mekli, of the University of Manchester in England.

“This association, of course, does not mean causality, therefore, further research is needed to understand and evaluate the potential mechanism,” Mekli said in a journal news release. “In addition, high levels of inflammation might be one of the biomarkers which helps to identify people who have elevated risk of developing dementia in the near future.”

The U.S. National Cancer Institute defines systemic inflammation as a serious condition involving inflammation throughout the whole body. This may be caused by an infection, trauma, surgery, ischemia (lack of blood supply to a part of the body), or certain conditions, such as an autoimmune disorder or pancreatitis.

Data from the U.K. Biobank on a half-million people showed the association between dementia and systemic inflammation, according to the authors.

Researchers evaluated the relationship between biomarkers of inflammation and performance on tests of memory and thinking, assessed at the same time as the biomarkers and years later. They were tested yet again if they were later diagnosed with dementia.

The analysis accounted for a variety of relevant factors, including whether participants had a variant of the APOE gene that is known to be associated with higher risk of dementia.

The team found that higher levels of inflammatory biomarker levels were associated with increased risk of dementia diagnoses up to 11 years later.

These elevated inflammatory biomarkers were also associated with worse performance on certain test measures, including tasks related to prospective memory, fluid intelligence and reaction time at baseline and again after four to 13 years.

While other known biomarkers, such as APOE status, appear to have a stronger association with dementia, what this research showed could be an additional useful tool for identifying people who may be at higher risk of developing the condition.

Further research will be needed to better understand the inflammation-dementia link, the authors said.

More information

The U.S. National Institute on Aging has more on Alzheimer's disease.

SOURCE: PLOS ONE, news release, July 19, 2023