For healthy older adults, antibiotic use is not associated with an increased risk of cognitive impairment or dementia, according to a study published in the Dec. 18, 2024, online issue. Neurology®the medical journal of the American Academy of Neurology.
Cognitive disorders occur when a person experiences subtle changes in thinking and memory, such as forgetting events more often and losing objects more often. Dementia occurs when thinking and memory problems become more advanced and affect a person’s ability to perform daily tasks.
Previous research has shown that antibiotics disrupt the gut microbiome, the community of tiny organisms that live in our intestines and support digestion. Because the gut microbiome has been shown to be important for maintaining overall health and possibly cognitive function, there have been concerns that antibiotics could have a long-term detrimental effect on the brain. Given that older adults are more likely to be prescribed antibiotics and are also at greater risk for cognitive decline, these findings provide certainty about the use of these medications.”
Andrew T. Chan, MD, MPH, study author from Harvard Medical School in Boston, Massachusetts
The study involved 13,571 healthy people over the age of 70. Researchers defined healthy as having no heart disease, dementia, serious physical disabilities or health problems that could shorten their lives to less than five years. All participants were free of cognitive impairment and dementia during the first two years of the study. During this time, researchers determined participants’ antibiotic use by reviewing prescription data. In total, 63% of people used antibiotics at least once during that period.
The participants were divided into two groups: those who were taking antibiotics and those who had never used antibiotics. Researchers also divided them into groups based on the number of antibiotic prescriptions they had in the first two years, from zero to five or more prescriptions, so they could assess whether more antibiotics increased a person’s risk.
Participants were then followed for an average of another five years, with 461 people developing dementia and 2,576 people developing cognitive impairment.
Researchers then examined whether antibiotic use during the first two years was associated with changes over time in thinking and memory skills.
Participants underwent a battery of cognitive tests at the start of the study, after one year, and every two years thereafter. Tests measured thinking and memory skills such as attention, executive function and language. Researchers then looked at the scores and compared people who took antibiotics with those who did not. They found no difference between the two groups.
After adjusting for factors such as family history of dementia, cognitive function at the start of the study, and medications known to affect cognition, researchers found that antibiotic use was not associated with increased risks of cognitive impairment or dementia compared to not using antibiotics. these medications.
Researchers also found no association with cumulative antibiotic use, continued use and specific types of antibiotics.
A limitation of the study was that it followed participants for a short period of time, meaning researchers could not determine whether there might be long-term effects of antibiotic use on cognition. Chan noted that longer studies are needed.
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Magazine reference:
Cai, W. & Gross, A., (2024) Are antibiotics associated with cognitive decline? Not for healthy older adults. Neurology. doi.org/10.1212/WNL.0000000000210255.