• Posted December 20, 2024

Antibiotics Do Not Increase Risks for Cognitive Decline, Dementia in Older Adults, New Data Says

Seniors with an infection can take antibiotics without fear of harming their brain health.

Antibiotics don’t appear to increase the risk of cognitive decline or dementia in older adults, researchers report in the journal Neurology.

“Given that older adults are more frequently prescribed antibiotics and are also at higher risk for cognitive decline, these findings offer reassurance about using these medications,” senior researcher Dr. Andrew Chan, a professor with Harvard Medical School, said in a news release from the American Academy of Neurology.

Previous studies have linked gut health to brain health, researchers said in background notes. The human gut contains trillions of microorganisms, and some have been shown to enhance and others to drain brain power.

“Antibiotics have been found in previous research to disrupt the gut microbiome, which is the community of tiny organisms that live in our intestines and support digestion,” Chan said.

“Because the gut microbiome has been found to be important for maintaining overall health, and possibly cognitive function, there was concern that antibiotics may have a harmful long-term effect on the brain,” he continued.

For this study, researchers tracked data on more than 13,500 healthy Australian seniors older than 70 who took part in a clinical trial testing the health benefits of daily low-dose aspirin.

Participants’ use of antibiotics was determined by reviewing prescription records, researchers said. About 63% used antibiotics at least once during a two-year period.

The seniors’ brain health was then tracked for an average of five more years. They took brain function tests at regular intervals that measured skills like memory, attention, executive function, language and reasoning.

During that time, more than 460 developed dementia and nearly 2,600 developed cognitive impairment -- early problems with memory and thinking that foreshadow a slip into dementia.

Researchers found no cognitive differences between those who took antibiotics and those who didn’t, results show.

What's more, antibiotic use was not associated with either cognitive impairment or dementia, after adjusting for other risk factors for brain decline, researchers said.

The team also found no association between cognitive problems and cumulative antibiotic use over time, continued use of antibiotics, or any specific types of antibiotics.

However, both Chan and the writers of an accompanying editorial said more research is needed to ensure no link between antibiotics and cognitive decline.

For example, the new study only followed seniors for a short period of time, Chan said. Extended studies are needed to confirm that antibiotics don’t interfere with long-term brain health.

And because the study relied on prescription records, it couldn’t precisely track people’s actual antibiotic use, noted the Neurology editorial co-written by Wenjie Cai and Alden Gross, epidemiologists in aging with the Johns Hopkins Bloomberg School of Public Health in Baltimore, MD.

The new study’s results “highlighted the need for future studies to document precise dosage and duration of antibiotic use and to explore potential dose-response relationships,” the editorial said, as well as the need to “investigate the impact of antibiotics from different classes and their interactions on cognition.”

More information

The Society for Neuroscience has more on the connection between the gut and the brain.

SOURCE: American Academy of Neurology, news release, Dec. 18, 2024