Use of Antibiotics and Cognitive Function in Older US Adults

Abstract Background To investigate the relationship between antibiotic use and subsequent cognitive function in older adults. Older adults who use antibiotics will have lower cognitive function over time. Methods In this longitudinal study of a representative sample of older U.S. adults (N = 2,939, National Social Life, Health, and Aging Project), we directly recorded antibiotic use during a home interview at baseline. Five years later, cognition and dementia were assessed (modified Montreal Cognitive Assessment [MoCA-SA] and reported physician diagnosis of dementia). Associations were tested using logistic regression, adjusting for age, gender, race/ethnicity, education, comorbidities, other medication use, and baseline cognition (Short Portable Mental Status Questionnaire). Results Older US adults who used antibiotics were less likely to score at or above the 85th percentile of MoCA-SA scores 5 years later (OR 0.27, 95% CI 0.13–0.58). There was no statistically significant association between antibiotic use and interval diagnosis of dementia, which was rare in this relatively healthy sample of older adults living at home. Conclusion Antibiotic use is associated with worse cognitive function five years later. This epidemiologic evidence is consistent with the effects of a disrupted gut microbiome on brain function or direct effects on the central nervous system.