{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,22]],"date-time":"2026-04-22T19:42:16Z","timestamp":1776886936286,"version":"3.51.2"},"reference-count":32,"publisher":"Oxford University Press (OUP)","issue":"4","license":[{"start":{"date-parts":[[2026,4,22]],"date-time":"2026-04-22T00:00:00Z","timestamp":1776816000000},"content-version":"vor","delay-in-days":21,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004359","name":"Swedish Research Council","doi-asserted-by":"publisher","award":["2020-02021"],"award-info":[{"award-number":["2020-02021"]}],"id":[{"id":"10.13039\/501100004359","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004359","name":"Swedish Research Council","doi-asserted-by":"publisher","award":["2025-02685"],"award-info":[{"award-number":["2025-02685"]}],"id":[{"id":"10.13039\/501100004359","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100006736","name":"\u00d6rebro University Hospital Research Foundation","doi-asserted-by":"crossref","award":["OLL-986849"],"award-info":[{"award-number":["OLL-986849"]}],"id":[{"id":"10.13039\/501100006736","id-type":"DOI","asserted-by":"crossref"}]},{"name":"Swedish state under the agreement between the Swedish government and the county councils"},{"name":"ALF agreement","award":["OLL-961742"],"award-info":[{"award-number":["OLL-961742"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,4,8]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background and Aims<\/jats:title>\n                    <jats:p>Limited statistical power has hampered previous estimates of concordance between relatives and heritability in inflammatory bowel diseases (IBD). To examine the genetic component of Crohn\u2019s disease and ulcerative colitis, we established the largest nationwide IBD twin cohort to date and assessed estimates of concordance and heritability.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We used the Swedish Twin Registry to identify all twins from complete pairs with known zygosity born between 1886 and 2004. The Swedish National Patient Register was used to identify all patients diagnosed with IBD. We calculated proband concordance rates and fitted a model estimating explained variance in diseases due to genetics (ie, the heritability), environment shared between twins, and environment unique to each twin.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>A cohort of 111\u00a0080 twins was followed until a median age of 62.2\u2009years, during which 964 individuals were diagnosed with IBD. The proband concordance rate for Crohn\u2019s disease was 0.30 in monozygotic pairs and 0.02 in dizygotic pairs. The corresponding rates for ulcerative colitis were 0.15 and 0.03. After adjusting for sex and birth year, heritability was estimated to be 0.78 (95% CI: 0.68-0.87) for Crohn\u2019s disease and 0.57 (95% CI: 0.46-0.69) for ulcerative colitis.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>In this large population-based twin study, the heritability of Crohn\u2019s disease was 0.78 and 0.57 for ulcerative colitis. These findings highlight the disparity between heritability estimates from twin studies and those inferred from genome-wide association studies, underscoring the need for continued exploration of the genetic basis of IBD.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/ecco-jcc\/jjag044","type":"journal-article","created":{"date-parts":[[2026,4,2]],"date-time":"2026-04-02T11:50:59Z","timestamp":1775130659000},"source":"Crossref","is-referenced-by-count":0,"title":["Heritability of Crohn\u2019s disease and ulcerative colitis: a Swedish nationwide population-based twin study"],"prefix":"10.1093","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4329-1659","authenticated-orcid":false,"given":"Olle","family":"Gr\u00e4nn\u00f6","sequence":"first","affiliation":[{"name":"Department of Laboratory Medicine, Clinical Microbiology, Faculty of Medicine and Health, \u00d6rebro University , \u00d6rebro,","place":["Sweden"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Joel","family":"Thunberg","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology, Faculty of Medicine and Health, \u00d6rebro University , \u00d6rebro,","place":["Sweden"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1024-5602","authenticated-orcid":false,"given":"Jonas F","family":"Ludvigsson","sequence":"additional","affiliation":[{"name":"Department of Medical Epidemiology and Biostatistics, Karolinska Institutet , Solna,","place":["Sweden"]},{"name":"Department of Pediatrics, \u00d6rebro University Hospital , \u00d6rebro,","place":["Sweden"]},{"name":"Department of Medicine, Columbia University College of Physicians and Surgeons , New York, NY,","place":["United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3765-2067","authenticated-orcid":false,"given":"Ralf","family":"Kuja-Halkola","sequence":"additional","affiliation":[{"name":"Department of Medical Epidemiology and Biostatistics, Karolinska Institutet , Solna,","place":["Sweden"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3887-9519","authenticated-orcid":false,"given":"Carl M\u00e5rten","family":"Lindqvist","sequence":"additional","affiliation":[{"name":"Faculty of Medicine and Health, School of Medical Sciences, \u00d6rebro University , \u00d6rebro,","place":["Sweden"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0122-7234","authenticated-orcid":false,"given":"Jonas","family":"Halfvarson","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology, Faculty of Medicine and Health, \u00d6rebro University , \u00d6rebro,","place":["Sweden"]}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"286","published-online":{"date-parts":[[2026,4,22]]},"reference":[{"key":"2026042214540682500_jjag044-B1","doi-asserted-by":"publisher","first-page":"527","DOI":"10.1038\/s41586-020-2025-2","article-title":"Pathway paradigms revealed from the genetics of inflammatory bowel disease","volume":"578","author":"Graham","year":"2020","journal-title":"Nature"},{"key":"2026042214540682500_jjag044-B2","doi-asserted-by":"publisher","first-page":"1166","DOI":"10.1111\/apt.18263","article-title":"Review article: Prevention of inflammatory bowel disease\u2014The path forward","volume":"60","author":"Bronze","year":"2024","journal-title":"Aliment Pharmacol Ther"},{"key":"2026042214540682500_jjag044-B3","doi-asserted-by":"publisher","first-page":"990","DOI":"10.1136\/gut.29.7.990","article-title":"Ulcerative colitis and Crohn\u2019s disease in an unselected population of monozygotic and dizygotic twins. 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