Research published in the journal Gut suggests frequent use of antibiotics may increase the risk of inflammatory bowel disease (IBD) – Chron’s disease and ulcerative colitis – among those over 40.
The findings indicate the risk appears cumulative and greatest 1-2 years after use and for those antibiotics that target gut infections.
The researchers drew on national medical data from 2000 to 2018 for Danish citizens aged 10 upwards who hadn’t been diagnosed with IBD.
They specifically wanted to know if the timing and dose of antibiotics might be important for the development of IBD and whether this varied by IBD and antibiotic type.
More than 6.1 million people were included in the study, just over half of whom were female.
In total, 5.5 million (91%) were prescribed at least one course of antibiotics between 2000 and 2018.
During this period, 36,017 new cases of ulcerative colitis and 16,881 new cases of Crohn’s disease were diagnosed.
Overall, compared with no antibiotic use, the use of these medications was associated with a higher risk of developing IBD, regardless of age. But older age was associated with the highest risk.
Those aged 10-40 were 28% more likely to be diagnosed with IBD; 40- 60-year-olds were 48% more likely to do so, while the over-60s were 47% more likely to do so.
The risks were slightly higher for Crohn’s disease than they were for ulcerative colitis: 40% among 10-40-year-olds; 62% among 40-60-year-olds; and 51% among the over-60s.
The risk seemed to be cumulative, with each subsequent course adding an additional 11%, 15%, and 14% heightened risk, according to the age band.
The highest risk of all was observed among those prescribed 5 or more courses of antibiotics: 69% heightened risk for 10–40-year-olds; a doubling in risk for 40–60-year-olds; and a 95% heightened risk for the over-60s.
Timing also seemed to be influential, with the highest risk for IBD occurring 1–2 years after antibiotic exposure, with each subsequent year thereafter associated with a lowering in risk.
Specifically, among 10–40-year-olds, IBD risk was 40% higher 1–2 years after taking antibiotics compared with 13% 4–5 years later. The equivalent figures for 40–60-year-olds were 66% vs 21% and for the over-60s 63% vs 22%.
While this is an observational study, and therefore can’t establish cause, the researchers say that limiting prescriptions for antibiotics may not only help to curb antibiotic resistance but may also help lower the risk of IBD.
“The association between antibiotic exposure and the development of IBD underscores the importance of antibiotic stewardship as a public health measure, and suggests the gastrointestinal microbiome as an important factor in the development of IBD, particularly among older adults,” they conclude.
