AIM
To summarise the current literature and define patterns
of disease in migrant and racial groups.
METHODS
A structured key word search in Ovid Medline and
EMBASE was undertaken in accordance with PRISMA
guidelines. Studies on incidence, prevalence and disease
phenotype of migrants and races compared with indigenous
groups were eligible for inclusion.
RESULTS
Thirty-three studies met the inclusion criteria. Individual
studies showed significant differences in incidence,
prevalence and disease phenotype between migrants or
race and indigenous groups. Pooled analysis could only
be undertaken for incidence studies on South Asians
where there was significant heterogeneity between the
studies [95% for ulcerative colitis (UC), 83% for Crohn’
s disease (CD)]. The difference between incidence
rates was not significant with a rate ratio South Asian:
Caucasian of 0.78 (95%CI: 0.22-2.78) for CD and
1.39 (95%CI: 0.84-2.32) for UC. South Asians showed
consistently higher incidence and more extensive UC
than the indigenous population in five countries. A
similar pattern was observed for Hispanics in the United
States. Bangladeshis and African Americans showed an
increased risk of CD with perianal disease.
CONCLUSION
This review suggests that migration and race influence the risk of developing inflammatory bowel disease.
This may be due to different inherent responses upon
exposure to an environmental trigger in the adopted
country. Further prospective studies on homogenous
migrant populations are needed to validate these observations,
with a parallel arm for in-depth investigation of
putative drivers.