Published online Oct 28, 2019. doi: 10.3748/wjg.v25.i40.6145
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
Processing time: 147 Days and 13.2 Hours
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.