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Antibiotics are one of the
most commonly prescribed drugs in the world. They’re used to treat many
different bacterial infections. While most people may only be on a course of
antibiotics for a week or two at a time, some may take antibiotics for a longer
period to treat certain chronic conditions, such as pneumonia or acne.
While antibiotics can be
life-saving, long-term use can come with several side effects – not least of
which is the risk of bacteria developing antibiotic resistance. And now, a
recent study has also linked long-term antibiotic use by middle-aged women to
an increased risk of cognitive
decline.
To conduct their study, the researchers collected data from 14,542
participants who had taken part in the Nurses’ Health Study II. This study
monitored the health and wellbeing of nurses every two years between 2014-2018.
The average age of participants at the start of the study was 54.
The researchers recorded the participants’ antibiotic use up to
four years prior to the start of the study. Some women had taken long-term
antibiotics (two months or more) for a variety of conditions – such as
respiratory problems or acne. Others had not been prescribed any antibiotics.
The researchers measured cognitive ability using online tests that participants
completed, which measured factors such as learning and working memory.
–
can have negative effects on cognition up
to 11 years later.
Though few
studies have measured both antibiotic use and cognitive function in adults,
some studies have shown broad-spectrum antimicrobials (including antibiotics)
can affect our cognitive function –
causing side effects such as confusion, delirium and poorer attention in both
men and women, even after short-term use.
While this
recent study showed a link between long-term antibiotic use and cognitive
decline, the study has some of limitations to take into account. First, the
online cognitive test only assessed four functions. This means we don’t have a
full picture of cognitive health, and we do not know if there are other
cognitive deficits in addition to those measured in the study.
Another
shortfall is that researchers did not collect faecal samples. This means we
don’t actually know whether the microbiome changed significantly after
long-term antibiotic use – and whether this change persisted. Though the
researchers were able to show that antibiotic use had a greater link to poorer
cognitive function than other lifestyle factors (such as diet, or other health
conditions), it will still be important for future research to look at whether
the microbiome really plays a role in antibiotic use and cognitive function.
The age of the
participants is also an important factor, as the average age was 54 at the
start of the study – which is the time most women experience menopause.
Menopause causes hormonal changes that
can affect everything from how the immune system works, sleep quality, weight,
blood pressure and even concentration and thinking.
Some research
also shows that the menopause alters the microbiome.
As such, it will be important to future studies to include men in mid-life to
see whether they show similar effects.
These research
findings indicate that it’s important to pay attention to gut health at all
stages of life. Fortunately, there are many things you can do to make your
microbiome healthier – such as eating a high-fibre diet and using prebiotics
and probiotics. Fresh air and exercise also have positive effects on the
microbiome. Of course for persistent problems medical attention should be sought
Associate Professor in Cognitive Neuroscience,
Sheffield Hallam University
