Background: Europe has experienced an influx of migrants from Africa and Middle East over the last 5 years. Previous studies have shown that migrants moving to developed countries develop the higher incidence of the host country. We aimed to obtain data on incidence of inflammatory bowel disease (IBD) according to country of origin from the Epicom 2010 inception cohort before this significant migration flow to define the current epidemiology and how this might guide future studies.
Methods: Eight populations from 6 countries in the Epicom collaborative group took part. A new ethnicity field was created and integrated onto the existing validated Epicom database. The participants were asked to submit data on the country of origin of each patient from the 2010 inception cohort. Census data was used to provide the number of people in the background population and each incident case was categorised into indigenous vs migrant groups. Patients born in the host country but with a migrant background were classified as migrant. Crude incidence was calculated as cases/100,000/yr.
Results: Five populations had <13% migrant population (Table 1). Six regions had <5 migrants diagnosed with IBD. In the UK (Brent and Harrow population) the number of IBD cases was 31 in the indigenous population and 43 in migrants with a non-adjusted incidence rate of 15.5/100,000/yr and 15.7/100,000/yr respectively. Similarly, in Denmark (Herlev) the incidence for indigenous and migrant groups was 21.6/100,000/yr and 19.1/100,000/yr.
Conclusions: The 2010 cohort shows limited migration in most European participating countries except for the UK where the majority were South Asians. Incidence rates for migrant and indigenous populations were similar and reflected expected high incidence of western world. The incidence rate in migrants was higher than expected for people coming from less developed countries, which supports hypothesis of the influence of environmental factors. There may be differences between UC and CD but the numbers were too small to explore this distinction. The study was limited by the small migrant population with IBD and incomplete data from two regions. The anticipated change in population demographics following the recent influx of migrants to Europe presents a unique opportunity to study evolution of IBD with migration and explore putative environmental factors. The data from our study will set a baseline on which to compare future trends in disease epidemiology.