Q&A: Midlife antibiotic use in women linked to cognitive decline
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Women who reported at least 2 months of antibiotic exposure in midlife experienced small decreases in cognition, which may be due to changes in the gut microbiome, data published in PLoS One showed.
Researchers conducted a population-based cohort study among women nurses who reported lifestyle, medications and health-related factors in the Nurses’ Health Study II starting in 1989. In 2009, participants (mean age, 54.7 years) reported their antibiotic use over the past 4 years, which was considered their midlife antibiotic use. Then, between 2014 and 2018, participants self-administered the CogState neuropsychological battery. The results were used to assess cognitive decline in 14,542 women.
Compared with women who reported no antibiotic use, those who used antibiotics for at least 2 months had mean CogState scores that were lower for global cognition, for psychomotor speed and attention and for learning and working memory.
“Given the profound effect of antibiotic use on the gut microbiome — with prior studies showing alterations in functional potential at 2 and 4 years after antibiotic exposure — the gut-brain axis could be a possible mechanism for linking antibiotics to cognitive function,” the researchers wrote.
Healio spoke with co-senior author Andrew T. Chan, MD, MPH, professor of medicine at Harvard Medical School and vice chair of gastroenterology and chief of the clinical and translational epidemiology unit at Massachusetts General Hospital, to learn more about the findings and their implications.
Healio: Why did you conduct this study? Were any of your findings surprising?
Chan: A growing body of evidence supports that the gut microbiome may be linked to cognitive decline or the development of dementia. There is also evidence that long-term antibiotic use may alter the gut microbiome. Thus, our results were not surprising. Our results show that chronic antibiotic use in midlife was associated with cognitive function in later life, which supports a role for the gut microbiome in cognition.
Healio: What is the take-home message?
Chan: Our study supports a potential role of the gut microbiome in cognition, which opens new avenues of research into possible ways of modifying the gut microbiome to prevent cognitive decline with aging. This also underscores the importance of judicious use of antibiotics across the life course to minimize potential long-term consequences of altering the gut microbiome.
Healio: What are the clinical implications of your findings?
Chan: It is premature to recommend that women avoid antibiotics during midlife for the specific purpose of preventing cognitive decline. However, there are certainly many other cogent reasons for women to avoid using antibiotics without a clear clinical indication, such as to minimize the risk of developing future infections resistant to antibiotics or other complications associated with antibiotic use.
Healio: What research still needs to be done on this topic?
Chan: Additional research needs to be done to understand the specific mechanisms by which antibiotics or the gut microbiome might influence cognitive function. We also need further information on the impact of antibiotic use at different stages of life, including earlier in adulthood and in childhood.
Healio: Is there anything else you would like to highlight about the study/topic?
Chan: The gut microbiome may be associated with a chronic state of inflammation that may predispose to cognitive decline or poor brain health. It may also be associated with the production of specific proteins or metabolites that may influence cognition.