Figure 1 Environmental factors contributing to IBD pathogenesis Figure 1 | Environmental factors contributing to IBD pathogenesis. Environmental factors including conception, maternal influences on the fetus, mode of birth, early childhood and diet and lifestyle exposures during adulthood modify the risk of development of Crohn's disease and ulcerative colitis. Ananthakrishnan, A. N. et al. (2017) Environmental triggers in IBD: a review of progress and evidence Nat. Rev. Gastroenterol. Hepatol. doi:10.1038/nrgastro.2017.136