Background and Aims: Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease are inflammatory diseases of the gastrointestinal tract. The incidence of IBD is increasing in minority populations; however, little is known about the epidemiology and disease characteristics of IBD in Black women. Methods: Our study population included participants in the Black Women's Health Study. Diagnosis of IBD was self-reported through the biennial questionnaires starting at baseline in 1995. We estimated the incidence of IBD according to age and geographic region. A follow up supplementary questionnaire was also sent to a subset of participants who reported diagnosis of IBD to evaluate the accuracy of self-reported diagnosis and to assess disease characteristics. Results: Through December 31st 2021, a total of 609 cases of IBD were reported, of which 142 were prevalent at baseline (prevalence = 0.24%) and 467 were incident (crude incidence rate = 33.2/100, 000 person-years). The incidence of IBD was highest in the <30 years age group and similar across geographic region. Among the participants who responded to the supplementary questionnaire, 62.1% had confirmed diagnosis of IBD. Conclusions: In a large prospective cohort of US Black women, we found that the incidence of IBD was similar to previously published estimates in US white women. Future studies should focus on identifying risk factors for IBD in US Blacks.

AAY is a consultant for Janssen and receives research funding from Pfizer Medical Grants Program and Exact Sciences. HK has received grant funding from Pfizer and Takeda. HK has also received consulting fees from Takeda.

No direct funding for this study. Black Women's Health Study is supported by U01 CA164974.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

IRB at Boston University and Massachusetts General Hospital have approved this study. Protocol # 2022P000551

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Data underlying the study cannot be made publicly available due to ethical concerns about patient confidentiality. Data will be made available to qualified researchers on request to BWHS@bu.edu .