Epidemiology and risk factors for IBD

Nature Reviews Gastroenterology and Hepatology - Tập 12 Số 4 - Trang 205-217 - 2015
Ashwin N. Ananthakrishnan1
1Massachusetts General Hospital Crohn's and Colitis Centre, 165 Cambridge Street, 9th Floor, Boston, MA 02114, USA.

Tóm tắt

Từ khóa


Tài liệu tham khảo

Cosnes, J. et al. Epidemiology and natural history of inflammatory bowel diseases. Gastroenterology 140, 1785–1794 (2011).

Loftus, E. V. Jr Clinical epidemiology of inflammatory bowel disease: incidence, prevalence, and environmental influences. Gastroenterology 126, 1504–1517 (2004).

Abraham, C. & Cho, J. H. Inflammatory bowel disease. N. Engl. J. Med. 361, 2066–2078 (2009).

Molodecky, N. A. et al. Increasing incidence and prevalence of the inflammatory bowel diseases with time, based on systematic review. Gastroenterology 142, 46–54.e42 (2012).

Hugot, J. P. et al. Association of NOD2 leucine-rich repeat variants with susceptibility to Crohn's disease. Nature 411, 599–603 (2001).

Ogura, Y. et al. A frameshift mutation in NOD2 associated with susceptibility to Crohn's disease. Nature 411, 603–606 (2001).

Jostins, L. et al. Host–microbe interactions have shaped the genetic architecture of inflammatory bowel disease. Nature 491, 119–124 (2012).

Loftus, E. V. Jr. et al. Ulcerative colitis in Olmsted County, Minnesota, 1940–1993: incidence, prevalence, and survival. Gut 46, 336–343 (2000).

Loftus, E. V. Jr. et al. Crohn's disease in Olmsted County, Minnesota, 1940–1993: incidence, prevalence, and survival. Gastroenterology 114, 1161–1168 (1998).

Loftus, C. G. et al. Update on the incidence and prevalence of Crohn's disease and ulcerative colitis in Olmsted County, Minnesota, 1940–2000. Inflamm. Bowel Dis. 13, 254–261 (2007).

Nerich, V. et al. Geographical variations of inflammatory bowel disease in France: a study based on national health insurance data. Inflamm. Bowel Dis. 12, 218–226 (2006).

Khalili, H. et al. Geographical variation and incidence of inflammatory bowel disease among US women. Gut 61, 1686–1692 (2012).

Gearry, R. B. et al. High incidence of Crohn's disease in Canterbury, New Zealand: results of an epidemiologic study. Inflamm. Bowel Dis. 12, 936–943 (2006).

Bernstein, C. N. et al. Assessing inflammatory bowel disease-associated antibodies in Caucasian and First Nations cohorts. Can. J. Gastroenterol. 25, 269–273 (2011).

Odes, H. S. et al. Inflammatory bowel disease in the Bedouin Arabs of southern Israel: rarity of diagnosis and clinical features. Gut 32, 1024–1026 (1991).

Bernstein, C. N. et al. A population-based case control study of potential risk factors for IBD. Am. J. Gastroenterol. 101, 993–1002 (2006).

Mahid, S. S. et al. Inflammatory bowel disease and African Americans: a systematic review. Inflamm. Bowel Dis. 14, 960–967 (2008).

Reddy, S. I. & Burakoff, R. Inflammatory bowel disease in African Americans. Inflamm. Bowel Dis. 9, 380–385 (2003).

Thia, K. T. et al. An update on the epidemiology of inflammatory bowel disease in Asia. Am. J. Gastroenterol. 103, 3167–3182 (2008).

Ng, S. C. et al. Incidence and phenotype of inflammatory bowel disease based on results from the Asia–Pacific Crohn's and colitis epidemiology study. Gastroenterology 145, 158–165.e2 (2013).

Archampong, T. N. & Nkrumah, K. N. Inflammatory bowel disease in Accra: what new trends. West Afr. J. Med. 32, 40–44 (2013).

Ukwenya, A. Y. et al. Inflammatory bowel disease in Nigerians: still a rare diagnosis? Ann. Afr. Med. 10, 175–179 (2011).

Al-Mofarreh, M. A. & Al-Mofleh, I. A. Emerging inflammatory bowel disease in Saudi outpatients: a report of 693 cases. Saudi J. Gastroenterol. 19, 16–22 (2013).

Sood, A. & Midha, V. Epidemiology of inflammatory bowel disease in Asia. Indian J. Gastroenterol. 26, 285–289 (2007).

Probert, C. S. et al. Epidemiological study of ulcerative proctocolitis in Indian migrants and the indigenous population of Leicestershire. Gut 33, 687–693 (1992).

Probert, C. S. et al. Prevalence and family risk of ulcerative colitis and Crohn's disease: an epidemiological study among Europeans and south Asians in Leicestershire. Gut 34, 1547–1551 (1993).

Li, X. et al. Risk of inflammatory bowel disease in first- and second-generation immigrants in Sweden: a nationwide follow-up study. Inflamm. Bowel Dis. 17, 1784–1791 (2011).

Pinsk, V. et al. Inflammatory bowel disease in the South Asian pediatric population of British Columbia. Am. J. Gastroenterol. 102, 1077–1083 (2007).

Benchimol, E. I. et al. O-004 Inflammatory Bowel Disease in Immigrants to Canada and their Children: a Population-Based Cohort Study. Inflamm. Bowel Dis. 20 (Suppl. 1) S3–S4 (2014).

Damas, O. M. et al. Phenotypic manifestations of inflammatory bowel disease differ between Hispanics and non-Hispanic whites: results of a large cohort study. Am. J. Gastroenterol. 108, 231–239 (2013).

Halme, L. et al. Family and twin studies in inflammatory bowel disease. World J. Gastroenterol. 12, 3668–3672 (2006).

Khor, B., Gardet, A. & Xavier, R. J. Genetics and pathogenesis of inflammatory bowel disease. Nature 474, 307–317 (2011).

Liu, J. Z. & Anderson, C. A. Genetic studies of Crohn's disease: past, present and future. Best Pract. Res. Clin. Gastroenterol. 28, 373–386 (2014).

Orholm, M. et al. Concordance of inflammatory bowel disease among Danish twins. Results of a nationwide study. Scand. J. Gastroenterol. 35, 1075–1081 (2000).

Russell, R. K. & Satsangi, J. IBD: a family affair. Best Pract. Res. Clin. Gastroenterol. 18, 525–539 (2004).

Thompson, N. P. et al. Genetics versus environment in inflammatory bowel disease: results of a British twin study. BMJ 312, 95–96 (1996).

Tysk, C. et al. Ulcerative colitis and Crohn's disease in an unselected population of monozygotic and dizygotic twins. A study of heritability and the influence of smoking. Gut 29, 990–996 (1988).

Yang, H. et al. Familial empirical risks for inflammatory bowel disease: differences between Jews and non-Jews. Gut 34, 517–524 (1993).

Halfvarson, J. et al. Inflammatory bowel disease in a Swedish twin cohort: a long-term follow-up of concordance and clinical characteristics. Gastroenterology 124, 1767–1773 (2003).

Hugot, J. P. et al. Mapping a susceptibility locus for Crohn's disease on chromosome 16. Nature 29, 821–823 (1996).

Jostins, L. et al. Host-microbe interactions have shaped the genetic architecture of inflammatory bowel disease. Nature 491, 119–124 (2012).

VanDussen, K. L. et al. Genetic variants synthesize to produce paneth cell phenotypes that define subtypes of Crohn's disease. Gastroenterology 146, 200–209 (2014).

Van Limbergen, J., Radford-Smith, G. & Satsangi, J. Advances in IBD genetics. Nat. Rev. Gastroenterol. Hepatol. 11, 372–385 (2014).

Glocker, E. O. et al. Inflammatory bowel disease and mutations affecting the interleukin-10 receptor. N. Engl. J. Med. 361, 2033–2045 (2009).

Gevers, D. et al. The treatment-naive microbiome in new-onset Crohn's disease. Cell Host Microbe 15, 382–392 (2014).

Kostic, A. D., Xavier, R. J. & Gevers, D. The microbiome in inflammatory bowel disease: current status and the future ahead. Gastroenterology 146, 1489–1499 (2014).

Morgan, X. C. et al. Dysfunction of the intestinal microbiome in inflammatory bowel disease and treatment. Genome Biol. 13, R79 (2012).

Nagalingam, N. A. & Lynch, S. V. Role of the microbiota in inflammatory bowel diseases. Inflamm. Bowel Dis. 18, 968–984 (2012).

Manichanh, C. et al. The gut microbiota in IBD. Nat. Rev. Gastroenterol. Hepatol. 9, 599–608 (2012).

Castiglione, F. et al. Risk factors for inflammatory bowel diseases according to the “hygiene hypothesis”: a case-control, multi-centre, prospective study in Southern Italy. J. Crohns Colitis 6, 324–329 (2012).

Ng, S. C. et al. Environmental risk factors in inflammatory bowel disease: a population-based case-control study in Asia–Pacific. Gut http://dx.doi.org/10.1136/gutjnl-2014-307410 .

Timm, S. et al. Place of upbringing in early childhood as related to inflammatory bowel diseases in adulthood: a population-based cohort study in Northern Europe. Eur. J. Epidemiol. 29, 429–437 (2014).

Willing, B. P. et al. A pyrosequencing study in twins shows that gastrointestinal microbial profiles vary with inflammatory bowel disease phenotypes. Gastroenterology 139, 1844–1854.e1 (2010).

Lepage, P. et al. Twin study indicates loss of interaction between microbiota and mucosa of patients with ulcerative colitis. Gastroenterology 141, 227–236 (2011).

Darfeuille-Michaud, A. et al. High prevalence of adherent-invasive Escherichia coli associated with ileal mucosa in Crohn's disease. Gastroenterology 127, 412–421 (2004).

Martin, R. et al. The commensal bacterium Faecalibacterium prausnitzii is protective in DNBS-induced chronic moderate and severe colitis models. Inflamm. Bowel Dis. 20, 417–430 (2014).

Sokol, H. et al. Faecalibacterium prausnitzii is an anti-inflammatory commensal bacterium identified by gut microbiota analysis of Crohn disease patients. Proc. Natl Acad. Sci. USA 105, 16731–16736 (2008).

Sokol, H. et al. Low counts of Faecalibacterium prausnitzii in colitis microbiota. Inflamm. Bowel Dis. 15, 1183–1189 (2009).

Wu, G. D. et al. Linking long-term dietary patterns with gut microbial enterotypes. Science 334, 105–108 (2011).

David, L. A. et al. Diet rapidly and reproducibly alters the human gut microbiome. Nature 505, 559–563 (2014).

Norman, J. M. et al. Disease-specific alterations in the enteric virome in inflammatory bowel disease. Cell 160, 447–460 (2015).

Iliev, I. D. et al. Interaction between commensal fungi and the C-type lectin receptor Dectin-1 influence colitis. Science 8, 1314–1347 (2012).

Harries, A. D., Baird, A. & Rhodes, J. Non-smoking: a feature of ulcerative colitis. Br. Med. J. (Clin. Res. Ed.) 284, 706 (1982).

Mahid, S. S. et al. Smoking and inflammatory bowel disease: a meta-analysis. Mayo Clin. Proc. 81, 1462–1471 (2006).

Higuchi, L. M. et al. A prospective study of cigarette smoking and the risk of inflammatory bowel disease in women. Am. J. Gastroenterol. 107, 1399–1406 (2012).

Mahid, S. S. et al. Active and passive smoking in childhood is related to the development of inflammatory bowel disease. Inflamm. Bowel Dis. 13, 431–438 (2007).

Odes, H. S. et al. Effects of current cigarette smoking on clinical course of Crohn's disease and ulcerative colitis. Dig. Dis. Sci. 46, 1717–1721 (2001).

Cosnes, J. et al. Gender differences in the response of colitis to smoking. Clin. Gastroenterol. Hepatol. 2, 41–48 (2004).

Cosnes, J. What is the link between the use of tobacco and IBD? Inflamm. Bowel Dis. 14 (Suppl. 2) S14–S15 (2008).

Cosnes, J. et al. Effects of cigarette smoking on the long-term course of Crohn's disease. Gastroenterology 110, 424–431 (1996).

Cosnes, J. et al. Effects of current and former cigarette smoking on the clinical course of Crohn's disease. Aliment. Pharmacol. Ther. 13, 1403–1411 (1999).

Lakatos, P. L., Szamosi, T. & Lakatos, L. Smoking in inflammatory bowel diseases: good, bad or ugly? World J. Gastroenterol. 13, 6134–6139 (2007).

Cosnes, J. Tobacco and IBD: relevance in the understanding of disease mechanisms and clinical practice. Best Pract. Res. Clin. Gastroenterol. 18, 481–496 (2004).

Birrenbach, T. & Bocker, U. Inflammatory bowel disease and smoking: a review of epidemiology, pathophysiology, and therapeutic implications. Inflamm. Bowel Dis. 10, 848–859 (2004).

Persson, P. G., Hellers, G. & Ahlbom, A. Use of oral moist snuff and inflammatory bowel disease. Int. J. Epidemiol. 22, 1101–1103 (1993).

Hatoum, O. A., Heidemann, J. & Binion, D. G. The intestinal microvasculature as a therapeutic target in inflammatory bowel disease. Ann. NY Acad. Sci. 1072, 78–97 (2006).

McGilligan, V. E. et al. Hypothesis about mechanisms through which nicotine might exert its effect on the interdependence of inflammation and gut barrier function in ulcerative colitis. Inflamm. Bowel Dis. 13, 108–115 (2007).

Bergeron, V. et al. Current smoking differentially affects blood mononuclear cells from patients with Crohn's disease and ulcerative colitis: relevance to its adverse role in the disease. Inflamm. Bowel Dis. 18, 1101–1111 (2012).

Ananthakrishnan, A. N. et al. Genetic polymorphisms in metabolizing enzymes modifying the association between smoking and inflammatory bowel diseases. Inflamm. Bowel Dis. 20, 783–789 (2014).

Biedermann, L. et al. Smoking cessation alters intestinal microbiota: insights from quantitative investigations on human fecal samples using FISH. Inflamm. Bowel Dis. 20, 1496–1501 (2014).

Munyaka, P. M., Khafipour, E. & Ghia, J. E. External influence of early childhood establishment of gut microbiota and subsequent health implications. Front. Pediatr. 2, 109 (2014).

Parkes, G. C., Whelan, K. & Lindsay, J. O. Smoking in inflammatory bowel disease: impact on disease course and insights into the aetiology of its effect. J. Crohns Colitis 8, 717–725 (2014).

Andersson, R. E. et al. Appendectomy and protection against ulcerative colitis. N. Engl. J. Med. 344, 808–814 (2001).

Andersson, R. E. et al. Appendectomy is followed by increased risk of Crohn's disease. Gastroenterology 124, 40–46 (2003).

Kaplan, G. G. et al. The risk of developing Crohn's disease after an appendectomy: a meta-analysis. Am. J. Gastroenterol. 103, 2925–2931 (2008).

Cosnes, J. et al. Prior appendectomy and the phenotype and course of Crohn's disease. World J. Gastroenterol. 12, 1235–1242 (2006).

Gardenbroek, T. J. et al. The effect of appendectomy on the course of ulcerative colitis: a systematic review. Colorectal Dis. 14, 545–553 (2012).

Radford-Smith, G. L. What is the importance of appendectomy in the natural history of IBD? Inflamm. Bowel Dis. 14 (Suppl. 2), S72–S74 (2008).

Radford-Smith, G. L. et al. Protective role of appendicectomy on onset and severity of ulcerative colitis and Crohn's disease. Gut 51, 808–813 (2002).

Strachan, D. P. Hay fever, hygiene, and household size. BMJ 299, 1259–1260 (1989).

Radon, K. et al. Contact with farm animals in early life and juvenile inflammatory bowel disease: a case–control study. Pediatrics 120, 354–361 (2007).

Van Kruiningen, H. J. et al. Environmental factors in familial Crohn's disease in Belgium. Inflamm. Bowel Dis. 11, 360–365 (2005).

Barclay, A. R. et al. Systematic review: the role of breastfeeding in the development of pediatric inflammatory bowel disease. J. Pediatr. 155, 421–426 (2009).

Bager, P. et al. Cesarean section and offspring's risk of inflammatory bowel disease: a national cohort study. Inflamm. Bowel Dis. 18, 857–862 (2012).

Sood, A. et al. Low hygiene and exposure to infections may be associated with increased risk for ulcerative colitis in a North Indian population. Ann. Gastroenterol. 27, 219–223 (2014).

Bernstein, C. N. et al. Population-based case control study of seroprevalence of Mycobacterium paratuberculosis in patients with Crohn's disease and ulcerative colitis. J. Clin. Microbiol. 42, 1129–1135 (2004).

Chacon, O., Bermudez, L. E. & Barletta, R. G. Johne's disease, inflammatory bowel disease, and Mycobacterium paratuberculosis. Annu. Rev. Microbiol. 58, 329–363 (2004).

Feller, M. et al. Mycobacterium avium subspecies paratuberculosis and Crohn's disease: a systematic review and meta-analysis. Lancet Infect. Dis. 7, 607–613 (2007).

Selby, W. et al. Two-year combination antibiotic therapy with clarithromycin, rifabutin, and clofazimine for Crohn's disease. Gastroenterology 132, 2313–2319 (2007).

Gradel, K. O. et al. Increased short- and long-term risk of inflammatory bowel disease after salmonella or campylobacter gastroenteritis. Gastroenterology 137, 495–501 (2009).

Porter, C. K. et al. Infectious gastroenteritis and risk of developing inflammatory bowel disease. Gastroenterology 135, 781–786 (2008).

Garcia Rodriguez, L. A., Ruigomez, A. & Panes, J. Acute gastroenteritis is followed by an increased risk of inflammatory bowel disease. Gastroenterology 130, 1588–1594 (2006).

Jess, T. et al. Enteric Salmonella or Campylobacter infections and the risk of inflammatory bowel disease. Gut 60, 318–324 (2011).

Thompson, N. P. et al. Is measles vaccination a risk factor for inflammatory bowel disease? Lancet 345, 1071–1074 (1995).

Bernstein, C. N., Rawsthorne, P. & Blanchard, J. F. Population-based case–control study of measles, mumps, and rubella and inflammatory bowel disease. Inflamm. Bowel Dis. 13, 759–762 (2007).

Davis, R. L. et al. Measles-mumps-rubella and other measles-containing vaccines do not increase the risk for inflammatory bowel disease: a case–control study from the Vaccine Safety Datalink project. Arch. Pediatr. Adolesc. Med. 155, 354–359 (2001).

Cadwell, K. et al. Virus-plus-susceptibility gene interaction determines Crohn's disease gene Atg16L1 phenotypes in intestine. Cell 141, 1135–1145 (2010).

Ananthakrishnan, A. N., Issa, M. & Binion, D. G. Clostridium difficile and inflammatory bowel disease. Gastroenterol. Clin. North Am. 38, 711–728 (2009).

Singh, S., Graff, L. A. & Bernstein, C. N. Do NSAIDs, antibiotics, infections, or stress trigger flares in IBD? Am. J. Gastroenterol. 104, 1298–1313 (2009).

Penders, J. et al. Factors influencing the composition of the intestinal microbiota in early infancy. Pediatrics 118, 511–521 (2006).

Shaw, S. Y., Blanchard, J. F. & Bernstein, C. N. Association between the use of antibiotics in the first year of life and pediatric inflammatory bowel disease. Am. J. Gastroenterol. 105, 2687–2692 (2010).

Virta, L. et al. Association of repeated exposure to antibiotics with the development of pediatric Crohn's disease—a nationwide, register-based finnish case–control study. Am. J. Epidemiol. 175, 775–784 (2012).

Shaw, S. Y., Blanchard, J. F. & Bernstein, C. N. Association between the use of antibiotics and new diagnoses of Crohn's disease and ulcerative colitis. Am. J. Gastroenterol. 106, 2133–2142 (2011).

Kronman, M. P. et al. Antibiotic exposure and IBD development among children: a population-based cohort study. Pediatrics 130, e794–e803 (2012).

Chan, S. S. et al. Aspirin in the aetiology of Crohn's disease and ulcerative colitis: a European prospective cohort study. Aliment. Pharmacol. Ther. 34, 649–655 (2011).

Ananthakrishnan, A. N. et al. Aspirin, nonsteroidal anti-inflammatory drug use, and risk for Crohn disease and ulcerative colitis: a cohort study. Ann. Intern. Med. 156, 350–359 (2012).

Cornish, J. A. et al. The risk of oral contraceptives in the etiology of inflammatory bowel disease: a meta-analysis. Am. J. Gastroenterol. 103, 2394–2400 (2008).

Khalili, H. et al. Oral contraceptives, reproductive factors and risk of inflammatory bowel disease. Gut 62, 1153–1159 (2013).

Khalili, H. et al. Hormone therapy increases risk of ulcerative colitis but not Crohn's disease. Gastroenterology 143, 1199–1206 (2012).

Chapman-Kiddell, C. A., Davies, P. S., Gillen, L. & Radford-Smith, G. L. Role of diet in the development of inflammatory bowel disease. Inflamm. Bowel Dis. 16, 137–151 (2010).

Hou, J. K., Abraham, B. & El-Serag, H. Dietary intake and risk of developing inflammatory bowel disease: a systematic review of the literature. Am. J. Gastroenterol. 106, 563–573 (2011).

Amre, D. K. et al. Imbalances in dietary consumption of fatty acids, vegetables, and fruits are associated with risk for Crohn's disease in children. Am. J. Gastroenterol. 102, 2016–2025 (2007).

Ananthakrishnan, A. N. et al. A prospective study of long-term intake of dietary fiber and risk of Crohn's disease and ulcerative colitis. Gastroenterology 145, 970–977 (2013).

Galvez, J., Rodriguez-Cabezas, M. E. & Zarzuelo, A. Effects of dietary fiber on inflammatory bowel disease. Mol. Nutr. Food Res. 49, 601–608 (2005).

Roberts, C. L. et al. Translocation of Crohn's disease Escherichia coli across M-cells: contrasting effects of soluble plant fibres and emulsifiers. Gut 59, 1331–1339 (2010).

Ananthakrishnan, A. N. et al. Long-term intake of dietary fat and risk of ulcerative colitis and Crohn's disease. Gut 63, 776–784 (2014).

de Silva, P. S. et al. An association between dietary arachidonic acid, measured in adipose tissue, and ulcerative colitis. Gastroenterology 139, 1912–1917 (2010).

D'Souza, S. et al. Dietary patterns and risk for Crohn's disease in children. Inflamm. Bowel Dis. 14, 367–373 (2008).

Geerling, B. J. et al. Diet as a risk factor for the development of ulcerative colitis. Am. J. Gastroenterol. 95, 1008–1013 (2000).

Hart, A. R. et al. Diet in the aetiology of ulcerative colitis: a European prospective cohort study. Digestion 77, 57–64 (2008).

John, S. et al. Dietary n-3 polyunsaturated fatty acids and the aetiology of ulcerative colitis: a UK prospective cohort study. Eur. J. Gastroenterol. Hepatol. 22, 602–606 (2010).

Devkota, S. et al. Dietary-fat-induced taurocholic acid promotes pathobiont expansion and colitis in Il10−/− mice. Nature 487, 104–108 (2012).

Cabre, E. & Domenech, E. Impact of environmental and dietary factors on the course of inflammatory bowel disease. World J. Gastroenterol. 18, 3814–3822 (2012).

Costea, I. et al. Interactions between the dietary polyunsaturated fatty acid ratio and genetic factors determine susceptibility to pediatric Crohn's disease. Gastroenterology 146, 929–931 (2014).

Jantchou, P. et al. Animal protein intake and risk of inflammatory bowel disease: the E3N prospective study. Am. J. Gastroenterol. 105, 2195–201 (2010).

Chan, S. S. et al. Carbohydrate intake in the etiology of Crohn's disease and ulcerative colitis. Inflamm. Bowel Dis. 20, 2013–2021 (2014).

Zallot, C. et al. Dietary beliefs and behavior among inflammatory bowel disease patients. Inflamm. Bowel Dis. 19, 66–72 (2013).

Cantorna, M. T. & Mahon, B. D. D-hormone and the immune system. J. Rheumatol. Suppl. 76, 11–20 (2005).

Cantorna, M. T. & Mahon, B. D. Mounting evidence for vitamin D as an environmental factor affecting autoimmune disease prevalence. Exp. Biol. Med. (Maywood) 229, 1136–1142 (2004).

Cantorna, M. T. et al. Vitamin D status, 1,25-dihydroxyvitamin D3, and the immune system. Am. J. Clin. Nutr. 80, 1717S–1720S (2004).

Cantorna, M. T. et al. 1,25-Dihydroxycholecalciferol prevents and ameliorates symptoms of experimental murine inflammatory bowel disease. J. Nutr. 130, 2648–2652 (2000).

Froicu, M. & Cantorna, M. T. Vitamin D and the vitamin D receptor are critical for control of the innate immune response to colonic injury. BMC Immunol. 8, 5 (2007).

Froicu, M. et al. A crucial role for the vitamin D receptor in experimental inflammatory bowel diseases. Mol. Endocrinol. 17, 2386–2392 (2003).

Froicu, M., Zhu, Y. & Cantorna, M. T. Vitamin D receptor is required to control gastrointestinal immunity in IL-10 knockout mice. Immunology 117, 310–318 (2006).

Mouli, V. P. & Ananthakrishnan, A. N. Review article: vitamin D and inflammatory bowel diseases. Aliment. Pharmacol. Ther. 39, 125–136 (2014).

Ananthakrishnan, A. N. et al. Higher predicted vitamin D status is associated with reduced risk of Crohn's disease. Gastroenterology 142, 482–489 (2012).

Ananthakrishnan, A. N. et al. Normalization of plasma 25-hydroxy vitamin D is associated with reduced risk of surgery in Crohn's disease. Inflamm. Bowel Dis. 19, 1921–1927 (2013).

Cerasi, M., Ammendola S. & Battistoni, A. Competition for zinc binding in the host-pathogen interaction. Front. Cell. Infect. Microbiol. 3, 108 (2013).

Haase, H. & Rink, L. Zinc signals and immune function. Biofactors 40, 27–40 (2014).

Lahiri, A. & Abraham, C. Activation of pattern recognition receptors up-regulates metallothioneins, thereby increasing intracellular accumulation of zinc, autophagy, and bacterial clearance by macrophages. Gastroenterology 147, 835–846 (2014).

El-Tawil, A. M. Zinc supplementation tightens leaky gut in Crohn's disease. Inflamm. Bowel Dis. 18, E399 (2012).

Chua, A. C. et al. Dietary iron enhances colonic inflammation and IL-6/IL-11–Stat3 signaling promoting colonic tumor development in mice. PLoS ONE 8, e78850 (2013).

Carrier, J. et al. Effect of oral iron supplementation on oxidative stress and colonic inflammation in rats with induced colitis. Aliment. Pharmacol. Ther. 15, 1989–1999 (2001).

Aamodt, G. et al. The association between water supply and inflammatory bowel disease based on a 1990–1993 cohort study in southeastern Norway. Am. J. Epidemiol. 168, 1065–1072 (2008).

Bernstein, C. N. et al. A prospective population-based study of triggers of symptomatic flares in IBD. Am. J. Gastroenterol. 105, 1994–2002 (2010).

Bonaz, B. L. & Bernstein, C. N. Brain–gut interactions in inflammatory bowel disease. Gastroenterology 144, 36–49 (2013).

Bailey, M. T. et al. Exposure to a social stressor alters the structure of the intestinal microbiota: implications for stressor-induced immunomodulation. Brain Behav. Immun. 25, 397–407 (2011).

Ghia, J. E. et al. Reactivation of inflammatory bowel disease in a mouse model of depression. Gastroenterology 136, 2280–2288.e1–e4 (2009).

Ananthakrishnan, A. N. et al. Association between depressive symptoms and incidence of Crohn's disease and ulcerative colitis: results from the Nurses' Health Study. Clin. Gastroenterol. Hepatol. 11, 57–62 (2013).

Bitton, A. et al. Predicting relapse in Crohn's disease: a biopsychosocial model. Gut 57, 1386–1392 (2008).

Goodhand, J. & Rampton, D. Psychological stress and coping in IBD. Gut 57, 1345–1347 (2008).

Goodhand, J. R. et al. Mood disorders in inflammatory bowel disease: relation to diagnosis, disease activity, perceived stress, and other factors. Inflamm. Bowel Dis. 18, 2301–2309 (2012).

Goodhand, J. R., Wahed, M. & Rampton, D. S. Management of stress in inflammatory bowel disease: a therapeutic option? Expert Rev. Gastroenterol. Hepatol. 3, 661–679 (2009).

Lerebours, E. et al. Stressful life events as a risk factor for inflammatory bowel disease onset: a population-based case-control study. Am. J. Gastroenterol. 102, 122–131 (2007).

Levenstein, S. et al. Stress and exacerbation in ulcerative colitis: a prospective study of patients enrolled in remission. Am. J. Gastroenterol. 95, 1213–1220 (2000).

Li, J. et al. Psychological stress and inflammatory bowel disease: a follow-up study in parents who lost a child in Denmark. Am. J. Gastroenterol. 99, 1129–1133 (2004).

Maunder, R. G. Evidence that stress contributes to inflammatory bowel disease: evaluation, synthesis, and future directions. Inflamm. Bowel Dis. 11, 600–608 (2005).

Mawdsley, J. E. & Rampton, D. S. Psychological stress in IBD: new insights into pathogenic and therapeutic implications. Gut 54, 1481–1491 (2005).

Rampton, D. Does stress influence inflammatory bowel disease? The clinical data. Dig. Dis. 27 (Suppl. 1), 76–79 (2009).

Sonnenberg, A. Occupational distribution of inflammatory bowel disease among German employees. Gut 31, 1037–1040 (1990).

Cook, M. D. et al. Forced treadmill exercise training exacerbates inflammation and causes mortality while voluntary wheel training is protective in a mouse model of colitis. Brain Behav. Immun. 33, 46–56 (2013).

Khalili, H. et al. Physical activity and risk of inflammatory bowel disease: prospective study from the Nurses' Health Study cohorts. BMJ 347, f6633 (2013).

Ananthakrishnan, A. N. et al. Sleep disturbance and risk of active disease in patients with Crohn's disease and ulcerative colitis. Clin. Gastroenterol. Hepatol. 11, 965–971 (2013).

Kinnucan, J. A., Rubin, D. T. & Ali, T. Sleep and inflammatory bowel disease: exploring the relationship between sleep disturbances and inflammation. Gastroenterol. Hepatol. (N. Y.) 9, 718–727 (2013).

Swanson, G. R., Burgess, H. J. & Keshavarzian, A. Sleep disturbances and inflammatory bowel disease: a potential trigger for disease flare? Expert Rev. Clin. Immunol. 7, 29–36 (2011).

Ananthakrishnan, A. N. et al. Sleep duration affects risk for ulcerative colitis: a prospective cohort study. Clin. Gastroenterol. Hepatol. 12, 1879–1886 (2014).

Ali, T. et al. Assessment of the relationship between quality of sleep and disease activity in inflammatory bowel disease patients. Inflamm. Bowel Dis. 19, 2440–2443 (2013).

Cosnes, J. et al. Smoking cessation and the course of Crohn's disease: an intervention study. Gastroenterology 120, 1093–1099 (2001).

Lunney, P. C. & Leong, R. W. Review article: Ulcerative colitis, smoking and nicotine therapy. Aliment. Pharmacol. Ther. 36, 997–1008 (2012).

Calabrese, E. et al. Low-dose smoking resumption in ex-smokers with refractory ulcerative colitis. J. Crohns Colitis 6, 756–762 (2012).

Noh, C. H. et al. Remission of ulcerative colitis after appendectomy: a case report [Korean]. Korean J. Gastroenterol. 56, 201–204 (2010).

Okazaki, K. et al. A patient with improvement of ulcerative colitis after appendectomy. Gastroenterology 119, 502–506 (2000).

Tighe, M. P., Cummings, J. R. & Afzal, N. A. Nutrition and inflammatory bowel disease: primary or adjuvant therapy. Curr. Opin. Clin. Nutr. Metab. Care 14, 491–496 (2011).

D'Argenio, V. et al. An altered gut microbiome profile in a child affected by Crohn's disease normalized after nutritional therapy. Am. J. Gastroenterol. 108, 851–852 (2013).

Cohen, S. A. et al. Clinical and mucosal improvement with specific carbohydrate diet in pediatric Crohn disease. J. Pediatr. Gastroenterol. Nutr. 59, 516–521 (2014).

Herfarth, H. H. et al. Prevalence of a gluten-free diet and improvement of clinical symptoms in patients with inflammatory bowel diseases. Inflamm. Bowel Dis. 20, 1194–1197 (2014).

Jorgensen, S. P. et al. Clinical trial: vitamin D3 treatment in Crohn's disease—-a randomized double-blind placebo-controlled study. Aliment. Pharmacol. Ther. 32, 377–383 (2010).

Lev-Tzion, R. et al. Omega 3 fatty acids (fish oil) for maintenance of remission in Crohn's disease. Cochrane Database of Systematic Reviews, Issue 2. Art. No.: CD006320 http://dx.doi.org/10.1002/14651858.CD006320.pub4 .

Uchiyama, K. et al. N-3 polyunsaturated fatty acid diet therapy for patients with inflammatory bowel disease. Inflamm. Bowel Dis. 16, 1696–1707 (2010).

Wahed, M. et al. Does psychological counseling alter the natural history of inflammatory bowel disease? Inflamm. Bowel Dis. 16, 664–669 (2010).

Timmer, A. et al. Psychological interventions for treatment of inflammatory bowel disease. Cochrane Database of Systematic Reviews, Issue 2. Art. No.: CD006913 http://dx.doi.org/10.1002/14651858.CD006913.pub2 .

Goodhand, J. R. et al. Do antidepressants influence the disease course in inflammatory bowel disease? A retrospective case-matched observational study. Inflamm. Bowel Dis. 18, 1232–1239 (2011).

Wild, C. P. Complementing the genome with an “exposome”: the outstanding challenge of environmental exposure measurement in molecular epidemiology. Cancer Epidemiol. Biomarkers Prev. 14, 1847–1850 (2005).

Kanaly, R. A. et al. Development of the adductome approach to detect DNA damage in humans. Antioxid. Redox Signal. 8, 993–1001 (2006).

Bogdanos, D. P. et al. Infectome: a platform to trace infectious triggers of autoimmunity. Autoimmun. Rev. 12, 726–740 (2013).

Crohn's and Colitis Canada Inflammatory Bowel Disease GEM Project. The GEM project [online] , (2015).

Connecticut Children's Medical Center. PROTECT [online] , (2015).

PROKIIDS data centre. PRO-KIIDS Data Centre [online] , (2015).

Lomer, M. C. et al. Efficacy and tolerability of a low microparticle diet in a double blind, randomized, pilot study in Crohn's disease. Eur. J. Gastroenterol. Hepatol. 13, 101–106 (2001).

Lomer, M. C. et al. Lack of efficacy of a reduced microparticle diet in a multi-centred trial of patients with active Crohn's disease. Eur. J. Gastroenterol. Hepatol. 17, 377–384 (2005).

Turner, D., Steinhart, A. H. & Griffiths, A. M. Omega 3 fatty acids (fish oil) for maintenance of remission in ulcerative colitis. Cochrane Database of Systematic Reviews, Issue 3. Art. No.: CD006443 http://dx.doi.org/10.1002/14651858.CD006443.pub2 .

Wright, R. & Truelove, S. C. A controlled therapeutic trial of various diets in ulcerative colitis. Br. Med. J. 2, 138–141 (1965).

Ritchie, J. K. et al. Controlled multicentre therapeutic trial of an unrefined carbohydrate, fibre rich diet in Crohn's disease. Br. Med. J. (Clin. Res. Ed.) 295, 517–520 (1987).

Bartel, G. et al. Ingested matter affects intestinal lesions in Crohn's disease. Inflamm. Bowel Dis. 14, 374–382 (2008).

Chiba, M. et al. Lifestyle-related disease in Crohn's disease: relapse prevention by a semi-vegetarian diet. World J. Gastroenterol. 16, 2484–2495 (2010).

Zachos, M., Tondeur, M. & Griffiths, A. M. Enteral nutritional therapy for induction of remission in Crohn's disease. Cochrane Database of Systematic Reviews, Issue 1. Art. No.: CD000542 http://dx.doi.org/10.1002/14651858.CD000542.pub2 .

Boye, B. et al. INSPIRE study: does stress management improve the course of inflammatory bowel disease and disease-specific quality of life in distressed patients with ulcerative colitis or Crohn's disease? A randomized controlled trial. Inflamm. Bowel Dis. 17, 1863–1873 (2011).