In Brief | Antimicrobials | Neurology |
Study Explores the Link Between Antibiotic Use and Cognitive Decline in Older Adults
Time to read: 02:46
Time to listen: 06:09
Originally Published: 14 January 2024
Sourced: Neurology
Type of article: In Brief
MedED Catalogue Reference: MIBRD002
Category: Antimicrobials
Cross Reference: Gerontology, Neurology
Keywords: antibiotics, antimicrobials, dementia, cognitive decline, gerontology
Among initially healthy older adults, neither single nor repeated antibiotic use was associated with incident dementia, cognitive impairment with no dementia, or accelerated cognitive decline.
This article is a review of a clinical trial originally published in Neurology, 14 January 2025 .This article does not represent the original research, nor is it intended to replace the original research. Access the full Disclaimer Information.
In Context
Antibiotics disrupt gut bacterial diversity and can result in long-lasting dysbiosis.
Because the gut microbiome is crucial for overall health and more recently has been associated with cognitive function, there is a concern that antibiotics could have a harmful long-term effect on neural health, particularly in older adults, who are more frequently prescribed these medications and who are a higher risk for developing cognitive decline.
Although emerging evidence from retrospective and claims-based studies has linked dysbiosis to cognitive function, prospective data was lacking.
Study Purpose
This study aimed to examine the prospective association of antibiotics with cognitive aging among initially healthy older adults.
Study Methodology
Prescription records were used to identify antibiotic use, categorizing participants as users (62.5%) or nonusers during the first 2 years of follow-up.
Participants underwent annual cognitive assessments using standardized tests of global cognition, episodic memory, language, executive function, and psychomotor speed.
Dementia diagnoses were based on the Diagnostic and Statistical Manual for Mental Disorders, Fourth Edition, criteria.
Findings
The study involved 13,571 healthy individuals, with mean age of 75 ( SD +/- 4.1 years), 54% of whom were women.
The median follow-up duration was 4.7 years.
The study found 461 cases of dementia and 2,576 cases of cognitive impairment with no dementia (CIND) among the participants during follow-up.
Antibiotic use during the first 2 years showed no association with incident dementia (hazard ratio [HR], 1.03; 95% CI, 0.84-1.25), CIND (HR, 1.02; 95% CI, 0.94-1.11), or subsequent declines in cognitive scores after adjusting for covariates.
There were no associations between cognitive outcomes and the cumulative frequency of antibiotic use, long-term use, or specific antibiotic classes (such as beta-lactams, tetracyclines, and sulfonamides).
Subgroup analyses revealed no significant differences in associations with age, sex, body mass index, baseline cognitive scores, or the use of medications affecting cognition.
Although prescription data may not reflect actual use, the study examined the frequency of antibiotics within a defined period to capture the extent and duration of antibiotic exposure. The results do not support an association between antibiotic-associated gut microbiome disruption and dementia risk.
A limitation of the study was the relatively short follow-up period, preventing researchers from determining if there may be long-term effects of antibiotic use on cognition.
Conclusion
These findings suggest that, in initially healthy older adults, antibiotic use was not linked to cognitive decline or the development of dementia. While antibiotics can alter the gut microbiome and have been associated with cognitive function in some studies, this study did not support a direct connection between antibiotic-associated gut disruption and dementia risk.
Importance of this study for South Africa
South Africa, with its growing elderly population, poor socio-economic conditions, and the highest global HIV/AIDS infection rate, is especially vulnerable to cognitive decline. It is estimated that one in every three individuals with HIV/AIDS will develop dementia.
Given the high rate of antibiotic prescribing in South Africa and the poor practices, particularly among adults, this study was crucial in ruling out antibiotic use as a contributing factor to dementia in these vulnerable populations. However, it should be noted that the trial was relatively small, and results may differ in larger studies.2
Access the Original Trial
Wang Y, Zhou Z, Broder JC, Woods RL, Orchard SG, Wolfe R, Ernst EJ, Ryan J, Ernst ME, Chan AT. Antibiotic Use and Subsequent Cognitive Decline and Dementia Risk in Healthy Older Adults. Neurology. 2025 Jan 14;104(1):e210129. doi: 10.1212/WNL.0000000000210129. Epub 2024 Dec 18. PMID: 39693592; PMCID: PMC11655135.
Additional References
1. Wolfe R, Murray AM, Woods RL, Kirpach B, Gilbertson D, Shah RC, Nelson MR, Reid CM, Ernst ME, Lockery J, Donnan GA, Williamson J, McNeil JJ. The aspirin in reducing events in the elderly trial: Statistical analysis plan. Int J Stroke. 2018 Apr;13(3):335-338. doi: 10.1177/1747493017741383. Epub 2017 Nov 7. PMID: 29111960; PMCID: PMC6380180.
1. Mobolaji Eniola Alabi, Sabiha Yusuf Essack, Antibiotic prescribing amongst South African general practitioners in private practice: an analysis of a health insurance database, JAC-Antimicrobial Resistance, Volume 4, Issue 5, October 2022, dlac101, https://doi.org/10.1093/jacamr/dlac101
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