April 4, 2017

expert reaction to study investigating long-term antibiotic use and the risk of bowel cancer precursor

Researchers publishing in Gut report long-term antibiotic use in early-to-middle adulthood was associated with increased risk of colorectal adenoma – the precursor for some colorectal cancers.

Dr Sheena Cruickshank, British Society for Immunology spokesperson, and Senior Lecturer in Immunology, University of Manchester, said:

“There is increasing evidence that our microbiota are important in regulating our immune responses and many aspects of our normal functions, including digesting food and producing essential metabolites and vitamins. Thus, anything that disturbs our gut bacteria, such as changes in diet, inflammation or antibiotic use, may have an impact on our health. This study has tried to control for factors such as diet between the antibiotic use and non-antibiotic use groups, which is good. However, it is not clear whether the subsequent findings were impacted by any factors within each group, as the study didn’t investigate whether diet within the antibiotic use group was a significant factor in determining who went on to develop these pre-cancerous lesions. Furthermore, the study does not consider whether there is impact on our microbiota from antibiotic usage in our food, as many farm animal are given antibiotics routinely when reared.

“This study’s findings imply that any risk is very slight and also quite variable. Whilst the data adds to our growing knowledge of the importance of the gut bacteria to our health, I would be concerned about advising people to avoid using antibiotics. Antibiotics are crucial medicines for treating bacterial infections and, if prescribed and used appropriately, can be life-saving.”

* ‘Long-term use of antibiotics and risk of colorectal adenoma’ by Cao et al. published in Gut on Tuesday 4 April.

Declared interests

Dr Sheena Cruickshank: No interests to declare.