Adults over 40 who regularly take antibiotics more prone to this disease

By Stephen Beech via SWNS

People over 40 who regularly take antibiotics are more likely to develop inflammatory bowel disease, warns a new study.

The risk seems to be the cumulative and greatest one to two years after taking a course of the tablets - and for those antibiotics targeting gut infections, say scientists.

Mounting evidence suggests that environmental factors are likely implicated in the development of inflammatory bowel disease (IBD).

Around seven million people worldwide have the condition, with the number expected to rise over the next decade.

One factor associated with the risk of IBD - Crohn’s disease and ulcerative colitis - in younger people is the use of antibiotics.

However, until now, it was not clear if the link might also apply to older people.

The research team 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 that 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 percent) were prescribed at least one course of antibiotics between 2000 and 2018.

During the study period, more than 36,000 new cases of ulcerative colitis and over 16,800 new cases of Crohn’s disease were diagnosed.

Study author Dr. Adam Faye, of New York University Langone Health, said: "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."

Those aged 10 to 40 were 28 percent more likely to be diagnosed with IBD; 40 to 60-year-olds were 48 percent more likely to do so, while those over 60 were 47 percent more likely to do so, according to the findings published online by the journal Gut.

The risks were slightly higher for Crohn’s disease than they were for ulcerative colitis: 40 percent among 10 to 40-year-olds; 62 percent among 40 to 60-year-olds; and 51 percent among those over 60.

Dr. Faye said: "The risk seemed to be cumulative, with each subsequent course adding an additional 11 percent, 15 percent, and 14 percent heightened risk, according to age band."

The findings showed that the highest risk of all was observed among those prescribed five or more courses of antibiotics: 69 percent heightened risk for 10 to 40-year-olds; a doubling in risk for 40 to 60-year-olds; and a 95 percent heightened risk for the over 60.

Dr. Faye said timing also seemed to be influential, with the highest risk for IBD occurring one to two years after antibiotic use, with each subsequent year thereafter associated with a lowering in risk.

The highest risk of IBD was associated with nitroimidazole and fluoroquinolone antibiotics, which are usually used to treat gut infections.

Dr. Faye said: "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 researchers pointed out that the study was observational and, as such, can’t establish cause.

However, they suggested that there are some "plausible" biological explanations for the findings, highlighting the natural reduction of both the resilience and range of microbes in the gut microbiome associated with aging, which antibiotic use is likely to compound.

Dr. Faye said: “Furthermore, with repeated courses of antibiotics, these shifts can become more pronounced, ultimately limiting recovery of the intestinal microbiota."

He says limiting prescriptions for antibiotics may not only help to curb antibiotic resistance but may also help lower the risk of IBD.

Dr. Faye added: “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."