The more antibiotics that seniors take, the greater their risk of inflammatory bowel disease (IBD), a new study suggests.
The findings could help explain some of the increase in Crohn’s disease and ulcerative colitis (common types of IBD) among older adults, according to the study authors.
“In older adults, we think that environmental factors are more important than genetics,” says lead researcher Dr. Adam Faye. He is an assistant professor of medicine and population health at NYU Grossman School of Medicine, in New York City.
“When you look at younger patients with new diagnoses of Crohn’s disease and ulcerative colitis, there’s generally a strong family history. But that is not the case in older adults, so it’s really something in the environment that is triggering it,” Faye said in a news release from the upcoming Digestive Disease Week meeting.
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What is the link between antibiotics and IBD?
For the study, Faye and his colleagues analyzed prescribing records for 2.3 million adults aged 60 and older in Denmark who were newly diagnosed with IBD from 2000 to 2018.
The investigators found a link between any antibiotic use and higher rates of IBD, and the risk rose significantly with each course of antibiotics.
Compared to those with no antibiotic use in the previous five years, one course of antibiotics was associated with a 27% higher risk of a new IBD diagnosis, two courses with a 55% higher risk and three courses with a 67% higher risk. Four courses were tied to a 96% higher risk, and five or more courses with a 236% higher risk, according to researchers.
Those who’d taken antibiotics within the previous one or two years had the highest rates of new IBD diagnoses, but the risk remained elevated for those who took the drugs in the previous two to five years, the study found.
The increased risk of IBD was found for all types of antibiotics except nitrofurantoin, which is commonly prescribed for