©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
Ethnic differences in inflammatory bowel disease: Results from the United Kingdom inception cohort epidemiology study
Ravi Misra, Samia Sakuma, Naila Arebi, Gastroenterology, St. Mark’s Hospital and Academic Institute, London HA1 3UJ, United Kingdom
Jimmy Limdi, The Pennine Acute Hospitals NHS Trust, Institute of Inflammation and Repair, University of Manchester, Manchester BL9 7TD, United Kingdom
Rachel Cooney, Tariq Iqbal, Gastroenterology, University Hospitals Birmingham, Birmingham B12 2TH, United Kingdom
Matthew Brookes, Gastroenterology, Royal Wolverhampton NHS Trust, London WV10 0QP, United Kingdom
Edward Fogden, Gastroenterology, Sandwell and West Birmingham Hospitals, Birmingham B71 4HJ, United Kingdom
Sanjeev Pattni, Gastroenterology, University Leicester Hospitals, Leicester LE1 5WW, United Kingdom
Naveen Sharma, Gastroenterology, Heartlands Hospital, Birmingham B9 5SS, United Kingdom
Pia Munkholm, Johan Burisch, Department of Gastroenterology, North Zealand University Hospital, Frederikssund 3600, Denmark
Author contributions: Misra R and Arebi N designed the study; Misra R analysed the data; Sakuma S supervised the study centres; Misra R and Arebi N wrote the paper; all authors critically appraised the paper and recruited patients to the study.
Institutional review board statement: The study was approved by the London Northwest NHS Trust and National Research Ethics Service (REC number14/EM/1290).
Informed consent statement: All study participants, or their legal guardian, provided informed written consent prior to study enrollment.
Conflict-of-interest statement: There are no conflicts of interest.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Ravi Misra, BSc, MRCP, Doctor, Consultant Gastroenterologist, Department of Gastroenterology, St. Mark’s Hospital and Academic Institute, Watford Rd, Harrow, London HA1 3UJ, United Kingdom. email@example.com
Received: June 3, 2019
Peer-review started: June 3, 2019
First decision: July 21, 2019
Revised: August 1, 2019
Accepted: September 9, 2019
Article in press: September 9, 2019
Published online: October 28, 2019
The current epidemiology of inflammatory bowel disease (IBD) in the multi-ethnic United Kingdom is unknown. The last incidence study in the United Kingdom was carried out over 20 years ago.
To describe the incidence and phenotype of IBD and distribution within ethnic groups.
Adult patients (> 16 years) with newly diagnosed IBD (fulfilling Copenhagen diagnostic criteria) were prospectively recruited over one year in 5 urban catchment areas with high South Asian population. Patient demographics, ethnic codes, disease phenotype (Montreal classification), disease activity and treatment within 3 months of diagnosis were recorded onto the Epicom database.
Across a population of 2271406 adults, 339 adult patients were diagnosed with IBD over one year: 218 with ulcerative colitis (UC, 64.3%), 115 with Crohn's disease (CD, 33.9%) and 6 with IBD unclassified (1.8%). The crude incidence of IBD, UC and CD was 17.0/100000, 11.3/100000 and 5.3/100000 respectively. The age adjusted incidence of IBD and UC were significantly higher in the Indian group (25.2/100000 and 20.5/100000) compared to White European (14.9/100000, P = 0.009 and 8.2/100000, P < 0.001) and Pakistani groups (14.9/100000, P = 0.001 and 11.2/100000, P = 0.007). The Indian group were significantly more likely to have extensive disease than White Europeans (52.7% vs 41.7%, P = 0.031). There was no significant difference in time to diagnosis, disease activity and treatment.
This is the only prospective study to report the incidence of IBD in an ethnically diverse United Kingdom population. The Indian ethnic group showed the highest age-adjusted incidence of UC (20.5/100000). Further studies on dietary, microbial and metabolic factors that might explain these findings in UC are underway.
Core tip: We performed a United Kingdom multicentre prospective cohort study to describe the incidence of inflammatory bowel disease and differences within ethnic groups. Seven urban centres with high ethnic background population recruited 339 cases over a 1 year period. Patients of Indian ethnicity were almost three times more likely to have UC than White Europeans. The impact of diet and environmental factors on this high risk population requires further study.