Getting sick often can increase the risk of dementia

Getting sick often can impact how quickly the brain ages and increase the risk of dementia or other forms of cognitive decline.

These are the results of a Tulane University study conducted in partnership with West Virginia University and the National Institutes of Occupational Safety and Health and published in the journal Brain, behavior and immunity. The study looked at aging male mice and found that repeated and intermittent experiences of mild inflammation, such as those caused by the flu or a seasonal head cold, caused impaired cognition and disrupted communication between neurons. in these mice.

We wanted to know if differences in the experience of infection could explain, at least in part, the differences in the rates of dementia that we observe in the population. The mice we were studying were adults in their late fifties who had intact faculties, yet when exposed to intermittent inflammation, they remembered less and their neurons functioned worse.”

Elizabeth Engler-Chiurazzi, PhD, lead author, behavioral neuroscientist in the Department of Neurosurgery at Tulane

This study is the first to model repeated and intermittent infections in mice and examine the long-term consequences for brain function and health.

Humans often suffer from infections and inflammation at significantly higher rates than laboratory mice. But given that impairments were seen in mice after just five intermittent inflammatory treatments, the cognitive change in humans might be more robust.

“Our mice only experienced intermittent disease-like inflammation a handful of times, so the fact that we observed impairments was surprising,” Engler-Chiurazzi said. “The effects were subtle, but that’s why I find these results significant: in a human, cognitive impairment from a similar number of inflammatory experiences might not be noticeable in their daily lives, but might have cumulative effects that have a negative impact on the aging brain.”

The results may have important implications for the standard of care regarding how infections are treated in the elderly and those at risk of dementia. And they are perhaps more relevant in light of the COVID-19 pandemic and ongoing research into the effects of long-COVID syndrome.

Going forward, Engler-Chiurazzi said more work needs to be done to understand why infections impact the brain and how to mitigate those effects. In addition, she hopes that follow-up studies will determine whether more vulnerable populations affected by health disparities face a higher burden of neurological effects.

“The biggest benefit of this research, in our view, is the importance of staying as healthy and infection-free as possible,” she said.