Women who undergo menopausal hormone therapy appear to have a higher risk for developing microscopic colitis, according to data from a large, nationwide cohort study published in Gastroenterology.
Kristin E. Burke, MD, of the gastroenterology unit at Massachusetts General Hospital, and colleagues used data from the Nurses’ Health Study (NHS) and NHSII that have documented reproductive and menopausal factors biennially dating back to 1988 and 1989, respectively.
“With over 20 years of follow-up and detailed and updated information on lifestyle factors, these cohorts offered us the unique opportunity to examine the relationship of menopausal and reproductive factors with risk of microscopic colitis,” they wrote.
Investigators analyzed data from 227,766 women who participated in the study cohorts without a baseline history of microscopic colitis. They determined risk factors after confirming diagnosis through pathology record reviews.
Burke and colleagues confirmed 275 incident cases of microscopic colitis over the course of 5,147,282 person-years.
They found that current menopausal hormone therapy (MHT) use was associated with increased risk for microscopic colitis compared with never-use (adjusted HR = 2.64; 96% CI, 1.78 – 3.9). The risk was higher with longer duration of use (P for trend < .0001) and went down after discontinuation (P for trend < .002).
Additionally, researchers found that ever-use of oral contraceptives (OCP) was associated with increased risk for microscopic colitis (aHR = 1.57; 95% CI, 1.16–2.13).
Burke and colleagues wrote that estrogen has been linked to the development and progression of Crohn’s disease and ulcerative colitis in the past, and it has been theorized that it modifies colonic epithelial permeability and mucosal immunity.
“Estrogen receptors are found on immune cells, including lymphocytes, where they may regulate immune response to gut flora,” they wrote. “Estrogen exposure through OCPs or MHT may thus lead to changes in mucosal immunity, heightening the abnormal inflammatory response to commensal bacteria seen in microscopic colitis.”
They called for further research to investigate the specific mechanisms through which estrogen spurs the development of microscopic colitis. – by Alex Young
Disclosures: Burke reports no relevant financial disclosures. Please see the full study for all other authors’ relevant financial disclosures.