Previous research, published in 2020, found a link between antibiotic use and the onset of IBD in young adults. Research led by Adam Faye, MD, an assistant professor of medicine and population health at NYU Grossman School of Medicine in New York City, looked at whether the same link could be found in older adults. Using the Danish National Prescription Register, researchers identified 2.3 million people ages 60 and older from 2000 to 2018 and assessed the number of antibiotics prescribed, the timing of antibiotics, and the impact of specific antibiotic classes on the development of IBD in older patients. During the 18-year study period, researchers found 10,773 new cases of ulcerative colitis and 3,825 new cases of Crohn’s, and exposure to antibiotics increased this risk, suggesting that environmental factors play a significant role in developing inflammatory bowel disease in this population. “When we think of IBD onset, we think of environmental factors and genetic factors as playing a role. So in essence, everything that is not genetically coded is considered an environmental risk factor or exposure [including antibiotic use],” explains Dr. Faye. “In younger patients, there seems to be a higher genetic risk and thus more of a family history of IBD. In older-onset IBD, family history of IBD is not as strong, suggesting less of a genetic risk, and that environment is playing more of a role to trigger IBD.”
IBD Risk Increased If Antibiotic Use Increased
New diagnoses were highest when antibiotics were prescribed one to two years before diagnosis, but a high risk remained for prescriptions in the two- to five-year period before diagnosis. This relationship was found for all types of antibiotics except nitrofurantoin, which is often prescribed for urinary tract infections. Antibiotics prescribed for gastrointestinal infections were the most likely to be associated with a new IBD diagnosis. “Inflammatory bowel disease, which can easily be overlooked in this age group, should be considered, especially when there’s a history of antibiotic prescriptions,” Faye says. He also notes the need for further research into this link. The authors did not have data on the reason for antibiotic use; as for example if it was prescribed for enteric (intestinal) infections, explains Benjamin Cohen, MD, a gastroenterologist and the clinical director of IBD with the Cleveland Clinic’s Digestive Disease & Surgery Institute, who was not involved with the study. “The findings should also alert physicians to consider IBD as a reason for new GI symptoms following multiple courses of antibiotics in previous years. This is important because physicians may be hesitant to perform invasive diagnostic procedures in older adults.” Many antibiotics can impact the intestinal microbiome, even if used to treat other illnesses, explains Faye. “Thus, in cases where a mild illness is being empirically treated or is expected to self-resolve in a few days, it may be more prudent to hold off on antibiotics right away.” In the future, Faye’s research team plans to focus on exploring the gut microbiome changes that result from antibiotic use and that may contribute to the development of IBD. “If we can determine the microbiome shifts that trigger new-onset IBD in older adults, perhaps there can be a role for probiotics or other therapies to restore the normal gut flora balance,” he says. “Once inflammation is present, treatment needs to focus on controlling the inflammation, which often requires medication therapy. However, there is ongoing research on the role of diet and stress in maintaining remission.”
