Fig. 1

Global epidemiological stage map of IBD evolution in 2020. According to the United Nations Development Classification (2020), regions are organized according to the expected current epidemiological stage of the evolution of inflammatory bowel disease (IBD). Areas of the first stage (sudden onset) are highlighted in green, areas of the second stage (accelerated incidence) are highlighted in yellow, and areas of the third stage (complex epidemic) are highlighted in orange. Areas with black borders are areas where population-based incidence or prevalence studies can be conducted. Data on incidence or prevalence are lacking in areas with gary boundaries (cited in Kaplan et al. [4])