For older adults in good health, the use of antibiotics does not lead to a higher chance of experiencing cognitive decline or dementia, according to a recent study published online on December 18, 2024, in the journal Neurology®, which is published by the American Academy of Neurology.
A recent study suggests that healthy seniors do not face an increased risk of cognitive impairment or dementia from using antibiotics.
Cognitive impairment refers to minor changes in memory and thinking abilities, such as frequently misplacing items or forgetting events. Dementia, on the other hand, involves more severe issues with cognition that interfere with daily life tasks.
Study author Andrew T. Chan, MD, MPH from Harvard Medical School in Boston, Massachusetts, pointed out that earlier research indicated antibiotics might disrupt the gut microbiome, which consists of the tiny organisms crucial for digestion residing in our intestines. “The gut microbiome plays an essential role in overall health and potentially cognitive function. Therefore, there was concern regarding possible negative long-term impacts on the brain from antibiotics,” Chan explained. This worry is particularly pertinent for older adults who are often prescribed antibiotics and are more likely to experience cognitive decline, making these study findings reassuring for their use.
The study tracked 13,571 healthy individuals over the age of 70, defining “healthy” as those without significant health issues such as heart disease, dementia, serious physical disabilities, or any conditions likely to reduce life expectancy to under five years. Initially, all participants were free from cognitive impairment and dementia. Researchers evaluated antibiotic use through prescription records during the initial two years, revealing that 63% of participants used antibiotics at least once during this period.
Participants were categorized into two groups: those who used antibiotics and those who had never used them. They were further divided based on the number of antibiotic prescriptions they received over the first two years, ranging from none to five or more, allowing researchers to examine whether a higher number of prescriptions increased cognitive risk.
The participants were monitored for an average of five additional years, during which 461 people developed dementia and 2,576 others experienced cognitive impairment. Researchers analyzed whether antibiotic use in the first two years was linked to changes in cognitive abilities over time.
To evaluate cognitive skills, participants underwent a series of tests at the study’s outset, again after one year, and every two years thereafter, checking areas such as attention, executive function, and language. When researchers compared scores from those who took antibiotics to those who did not, they found no significant differences between the two groups.
After accounting for variables like family history of dementia, baseline cognitive function, and other medications affecting cognition, researchers determined that antibiotic use did not correlate with an increased risk of cognitive impairment or dementia compared to non-users.
No links were detected concerning cumulative antibiotic use, ongoing use, or specific types of antibiotics.
One limitation of the study was its relatively short follow-up period, which limited researchers’ ability to assess any long-term effects of antibiotic usage on cognitive health. Chan emphasized the need for longer-term studies.
