Increased risk of IBD linked to regular use of antibiotics

Jan. 10, 2023

Frequent use of antibiotics may heighten the risk of inflammatory bowel disease—Crohn’s disease and ulcerative colitis—among the over 40s, suggests research published online in the journal Gut. Findings indicate the risk seems to be cumulative and greatest one to two years after use, and for those antibiotics targeting gut infections.

Mounting evidence suggests that environmental factors are likely implicated in the development of inflammatory bowel disease (IBD). Globally, close to 7 million people have the condition, with this number expected to rise over the next decade, according to researchers.

One factor associated with IBD risk in younger people is the use of antibiotics, but it’s not clear if this association might also apply in older people. To explore this further, 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 antibiotic 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, some 36,017 new cases of ulcerative colitis and 16,881 new cases of Crohn’s disease were diagnosed. Overall, compared with no antibiotic use, use of these drugs was associated with a higher risk of developing IBD, regardless of age. But older age was associated with the highest risk.

Timing also seemed to be influential, with the highest risk for IBD occurring one to two years after antibiotic exposure, with each subsequent year thereafter associated with a lowering in risk. As to antibiotic type, the highest risk of IBD was associated with the nitroimidazoles and fluoroquinolones, which are usually used to treat gut infections. These are known as broad-spectrum antibiotics because they indiscriminately target all microbes, not just those that cause disease. Nitrofurantoin was the only antibiotic type not associated with IBD risk at any age.

Narrow-spectrum penicillins were also associated with IBD, although to a much lesser extent. This adds weight to the notion that changes in the gut microbiome may have a key role and that many antibiotics have the potential to alter the make-up of microbes in the gut.

“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.

EurekAlert release