Antibiotics Not Linked to Short-Term Dementia Risk

TOPLINE:

There is no link between antibiotic use and an increased risk for dementia or cognitive impairment in healthy adults aged ≥ 70 years, a new study suggests. However, investigators note that the study follow-up may not have been long enough to identify potential long-term effects of antibiotic use on cognitive aging.

METHODOLOGY:

• This observational extension of a completed trial included more than 13,500 community-dwelling Australian adults (mean age, 75 years; 54% women) who were free of dementia, cardiovascular disease, independence-limiting physical disability, and life-limiting conditions at enrollment.
• Prescription records were used to identify antibiotic use, categorizing participants as users (62.5%) vs 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.
• The median follow-up duration was 4.7 years.

TAKEAWAY:

• Overall, 461 cases of dementia and 2576 cases of cognitive impairment with no dementia (CIND) were observed 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 also no associations between cognitive outcomes and the cumulative frequency of antibiotic use, long-term antibiotic 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.

IN PRACTICE:

“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,” study investigator Andrew T. Chan, MD, MPH, Harvard Medical School, Boston, said in a press release.

However, the authors of an accompanying editorial urged caution “when interpreting and implementing these findings to inform rigorous clinical practice.” “This study offers insights for clinicians and health care providers working with healthy older adults who share similar health profiles with those in this study,” the editorial authors wrote.

SOURCE:

The study was led by Yiqing Wang, Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston. The editorial was authored by Wenjie Cai, MD, and Alden Gross, PhD, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland. Both papers were published online on December 18 in Neurology.

LIMITATIONS:

Prescription data may not have reflected actual medication use. The relatively short duration of study follow-up limited the ability to determine the potential long-term effects of antibiotic use on cognitive aging. Additionally, since all participants were initially healthy and free of diagnosed dementia and independence-limiting physical disability at baseline, the findings may not be generalizable to the general older population or patients with underlying cognitive impairment.

DISCLOSURES:

The study was supported by the National Institute on Aging and the National Cancer Institute at the National Institutes of Health; the National Health and Medical Research Council of Australia; Monash University in Melbourne, Australia; and the Victorian Cancer Agency. One investigator reported receiving personal fees from pharmaceutical companies and serving as an investigator on a study previously supported by a private company, while another reported receiving investigator-initiated research funding from a pharmaceutical company. Full details are listed in the original article. The editorialists reported no targeted funding or conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.