A new study provides reassurance for healthy older adults who need to use antibiotics, finding no link between antibiotic use and an increased risk of cognitive impairment or dementia.
The research, published on December 18, 2024, in Neurology, counters earlier concerns that these medications might harm long-term brain health.
Cognitive impairment involves subtle changes in thinking and memory, such as frequently forgetting events or misplacing items. Dementia is more severe, affecting daily tasks and independence.
Because the gut microbiome—the collection of microorganisms in the intestines—is thought to influence overall health and possibly cognitive function, previous studies raised concerns about the potential effects of antibiotics, which are known to disrupt this microbial community.
“Older adults are often prescribed antibiotics and are at higher risk for cognitive decline, so this study offers important reassurance,” said study author Dr. Andrew T. Chan of Harvard Medical School.
The study included 13,571 adults aged 70 and older who were considered healthy, meaning they had no heart disease, dementia, severe physical disabilities, or life-threatening conditions. None of the participants showed signs of cognitive impairment or dementia during the first two years of the study.
Researchers reviewed prescription records to determine antibiotic use during these initial two years. Approximately 63% of participants used antibiotics at least once in this period. Participants were grouped based on their antibiotic use, ranging from no prescriptions to five or more.
Over the next five years, participants underwent cognitive tests to measure skills like attention, memory, language, and problem-solving. During this time, 461 people developed dementia, and 2,576 showed signs of cognitive impairment.
When comparing test results between those who used antibiotics and those who did not, researchers found no difference in thinking and memory skills.
Even after accounting for factors like family history of dementia, initial cognitive performance, and medications known to affect cognition, antibiotic use was not linked to increased risks of cognitive decline.
Additionally, the study found no associations between cognitive outcomes and the amount or duration of antibiotic use, nor with specific types of antibiotics.
The findings suggest that antibiotics, when prescribed and used appropriately, do not pose a threat to cognitive health in healthy older adults.
However, the study followed participants for only a few years, leaving questions about potential long-term effects unanswered. Dr. Chan emphasized the need for longer studies to explore this further.
This research provides peace of mind for older adults and their caregivers, highlighting that antibiotics, despite their impact on the gut microbiome, do not appear to harm cognitive function in the short to medium term.
It underscores the importance of using these medications as needed without unnecessary worry about their impact on brain health.
If you care about dementia, please read studies about Vitamin B9 deficiency linked to higher dementia risk, and flavonoid-rich foods could help prevent dementia.
For more information about brain health, please see recent studies that cranberries could help boost memory, and how alcohol, coffee and tea intake influence cognitive decline.
The research findings can be found in Neurology.
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