Epidemiology of inflammatory bowel diseases from west to east

The incidence and prevalence of inflammatory bowel disease (IBD) show considerable variation over time and across geographical regions. The first studies on the epidemiology of IBD were mainly from traditionally high-incidence areas, such as North America, and northern and western Europe. In the last two decades, more and more studies have been published from Eastern European and Asian countries with increasing incidence rates from some regions. According to recent studies, the high incidence and prevalence of IBD in some Western countries is plateauing and in some Eastern countries increasing incidences have been reported. In the era of new multicenter epidemiological studies with common methodology the direct comparison of incidences and prevalences has became possible. In the present review we summarized the currently available literatures on west-east differences in the incidences and prevalences of IBD.