Chronic Antibiotic Use in Midlife Could Cause Cognitive Decline

The gut microbiome is increasingly recognized to play a role in cognition and dementia. Antibiotic use impacts the gut microbiome and has been linked with chronic disease. Despite these data, there is no evidence supporting an association between long-term antibiotic use in adults and cognitive function.

In a recently published study, researchers from the Massachusetts General Hospital and Harvard Medical School found that the use of chronic midlife antibiotic use in women was linked to mild decreases in cognitive function 7 years later. The results appear in the journal PLoS ONE.

Study Development and Results

The brain-gut axis is believed to contribute to neuropsychiatric illnesses including depression, schizophrenia, autism, and anxiety. New evidence also suggests its role in the development of dementia. 

The researchers conducted a prospective study among 14,542 individuals from the Nurses’ Health Study II who completed a self-administered computerized neuropsychological test battery between 2014-2018. 

They found that women that reported at least 2 months of antibiotic exposure in midlife, with a mean age of 54.7 had lower mean cognitive scores seven years later after adjustment for age and educational attainment of the spouse and parent. 

They also observed that antibiotic use in midlife was significantly associated with subsequent poorer scores for global cognition, learning and working memory, and psychomotor speed and attention on a cognitive assessment 7 years later. 

The authors concluded that the relation of antibiotic use to cognition was roughly equivalent to that found for 3 to 4 years of aging. 


Raaj S. Mehta, et al. Association of midlife antibiotic use with subsequent cognitive function in women. 2022. PLoS ONE. 17(3): e0264649. 

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