Reply to “Biliary atresia: Does ethnicity matter?”
Authors: Cyriel Y. Ponsioen, Kirsten Boonstra
Journal: Journal of Hepatology (2012)

Biliary atresia: Does ethnicity matter?Journal of HepatologyVol. 57Issue 3PreviewWe wish to call the readership’s attention to the recent study by Boonstra et al. [1] on the systematic review that showed that the incidence and the prevalence of primary sclerosing cholangitis and primary biliary cirrhosis vary widely based on the geographical distribution. Further, it was previously observed that the severity and the incidence of primary sclerosing cholangitis were influenced by ethnicity [2,3]. We expanded here the scope of this methodology to another biliary disease, i.e. biliary atresia (BA), which is a destructive cholangiopathy of neonates that leads to biliary cirrhosis. Full-Text PDF Open AccessEpidemiology of primary sclerosing cholangitis and primary biliary cirrhosis: A systematic reviewJournal of HepatologyVol. 56Issue 5PreviewStudies on the epidemiology of primary sclerosing cholangitis (PSC) and primary biliary cirrhosis (PBC) show variable outcome. We aimed at systematically reviewing the incidence and prevalence rates, as well as geographical distribution and temporal trends of PSC and PBC. Full-Text PDF Open Access We welcome the comment of Girard et al. [[1]Girard M. Jannot A.-S. Besnard M. Caude A.H. Biliary atresia: does ethnicity matter?.J Hepatol. 2012; 57: 700-701Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar] to our systematic review on the epidemiology of primary sclerosing cholangitis (PSC) and primary biliary cirrhosis (PBC) [[2]Boonstra K. Beuers U. Ponsioen C.Y. Epidemiology of primary sclerosing cholangitis and primary biliary cirrhosis: a systematic review.J Hepatol. 2012; 56: 1181-1188Abstract Full Text Full Text PDF PubMed Scopus (405) Google Scholar]. The authors underscore the need for proper assessment of ethnicity in epidemiological studies of rare diseases such as biliary atresia, PSC, and PBC. The apparent familial risk, albeit with a low absolute risk, together with the reported genetic risk loci, point in the direction of a complex genetic predisposition belying both PSC and PBC. Recently, disparate associations with several genetic risk loci have been reported in PSC patients from various ethnic backgrounds [[3]Toy E. Balasubramanian S. Selmi C. Li C.-S. Bowlus C.L. The prevalence, incidence and natural history of primary sclerosing cholangitis in an ethnically diverse population.BMC Gastroenterol. 2011; 11: 83Crossref PubMed Scopus (70) Google Scholar]. For PBC, little is known about ethnic differences since the majority of studies have been performed with Caucasian patients. Notably, a large multicenter study in the US was performed comparing PBC patients with geographically and ethnically diverse backgrounds [[4]Peters M.G. Di Bisceglie A.M. Kowdley K.V. Flye N.L. Luketic V.A. Munoz S.J. et al.Differences between Caucasian, African American, and Hispanic patients with primary biliary cirrhosis in the United States.Hepatology. 2007; 46: 769-775Crossref PubMed Scopus (45) Google Scholar]. The authors showed more severe disease in African Americans and Hispanics compared to Caucasians. In addition, for inflammatory bowel disease, which is closely associated with PSC, it has been well documented that incidence rates in 2nd generation immigrants with a different ethnic background assume the same levels as those for the indigenous population, pointing towards environmental factors [5Probert C.S. Jayanthi V. Pinder D. Wicks A.C. Mayberry J.F. Epidemiological study of ulcerative proctocolitis in Indian migrants and the indigenous population of Leicestershire.Gut. 1992; 33: 687-693Crossref PubMed Scopus (212) Google Scholar, 6Pinsk V. Lemberg D.A. Grewal K. Barker C.C. Schreiber R.A. Jacobson K. Inflammatory bowel disease in the South Asian pediatric population of British Columbia.Am J Gastroenterol. 2007; 102: 1077-1083Crossref PubMed Scopus (129) Google Scholar, 7Mangat B.K. Evaschen C. Lee T. Yoshida E.M. Salh B. Ethnic variation in the annual rates of adult inflammatory bowel disease in hospitalized patients in Vancouver, British Columbia.Can J Gastroenterol. 2011; 25: 73-77Crossref PubMed Scopus (16) Google Scholar]. For PSC, population-based trends in incidence and prevalence rates with regard to ethnic background are lacking. One study from Southern Israel reported higher prevalence rates for PBC among Jews and immigrants compared to Arabs and native Israelis and in a study from Southeast Asia, the prevalence rate in the Chinese population was almost twice as high as in the Malay population, though the small number of included patients is a limitation of both studies. [8Delgado J. Sperber A.D. Novack V. Delgado B. Edelman L. Gaspar N. et al.The epidemiology of primary biliary cirrhosis in southern Israel.Isr Med Assoc J. 2005; 7: 717-721PubMed Google Scholar, 9Chong V.H. Telisinghe P.U. Jalihal A. Primary biliary cirrhosis in Brunei Darussalam.Hepatobiliary Pancreat Dis Int. 2010; 9: 622-628PubMed Google Scholar] The data presented by Girard et al. [[1]Girard M. Jannot A.-S. Besnard M. Caude A.H. Biliary atresia: does ethnicity matter?.J Hepatol. 2012; 57: 700-701Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar] exemplify our conclusion that large true population-based epidemiological studies with meticulous case-finding, case-ascertainment, as well as detailed phenotyping (including ancestry) are needed to provide clues for unraveling genetic and environmental risk factors for these diseases.Conflict of interestThe authors declared that they do not have anything to disclose regarding funding or conflict of interest with respect to this manuscript. We welcome the comment of Girard et al. [[1]Girard M. Jannot A.-S. Besnard M. Caude A.H. Biliary atresia: does ethnicity matter?.J Hepatol. 2012; 57: 700-701Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar] to our systematic review on the epidemiology of primary sclerosing cholangitis (PSC) and primary biliary cirrhosis (PBC) [[2]Boonstra K. Beuers U. Ponsioen C.Y. Epidemiology of primary sclerosing cholangitis and primary biliary cirrhosis: a systematic review.J Hepatol. 2012; 56: 1181-1188Abstract Full Text Full Text PDF PubMed Scopus (405) Google Scholar]. The authors underscore the need for proper assessment of ethnicity in epidemiological studies of rare diseases such as biliary atresia, PSC, and PBC. The apparent familial risk, albeit with a low absolute risk, together with the reported genetic risk loci, point in the direction of a complex genetic predisposition belying both PSC and PBC. Recently, disparate associations with several genetic risk loci have been reported in PSC patients from various ethnic backgrounds [[3]Toy E. Balasubramanian S. Selmi C. Li C.-S. Bowlus C.L. The prevalence, incidence and natural history of primary sclerosing cholangitis in an ethnically diverse population.BMC Gastroenterol. 2011; 11: 83Crossref PubMed Scopus (70) Google Scholar]. For PBC, little is known about ethnic differences since the majority of studies have been performed with Caucasian patients. Notably, a large multicenter study in the US was performed comparing PBC patients with geographically and ethnically diverse backgrounds [[4]Peters M.G. Di Bisceglie A.M. Kowdley K.V. Flye N.L. Luketic V.A. Munoz S.J. et al.Differences between Caucasian, African American, and Hispanic patients with primary biliary cirrhosis in the United States.Hepatology. 2007; 46: 769-775Crossref PubMed Scopus (45) Google Scholar]. The authors showed more severe disease in African Americans and Hispanics compared to Caucasians. In addition, for inflammatory bowel disease, which is closely associated with PSC, it has been well documented that incidence rates in 2nd generation immigrants with a different ethnic background assume the same levels as those for the indigenous population, pointing towards environmental factors [5Probert C.S. Jayanthi V. Pinder D. Wicks A.C. Mayberry J.F. Epidemiological study of ulcerative proctocolitis in Indian migrants and the indigenous population of Leicestershire.Gut. 1992; 33: 687-693Crossref PubMed Scopus (212) Google Scholar, 6Pinsk V. Lemberg D.A. Grewal K. Barker C.C. Schreiber R.A. Jacobson K. Inflammatory bowel disease in the South Asian pediatric population of British Columbia.Am J Gastroenterol. 2007; 102: 1077-1083Crossref PubMed Scopus (129) Google Scholar, 7Mangat B.K. Evaschen C. Lee T. Yoshida E.M. Salh B. Ethnic variation in the annual rates of adult inflammatory bowel disease in hospitalized patients in Vancouver, British Columbia.Can J Gastroenterol. 2011; 25: 73-77Crossref PubMed Scopus (16) Google Scholar]. For PSC, population-based trends in incidence and prevalence rates with regard to ethnic background are lacking. One study from Southern Israel reported higher prevalence rates for PBC among Jews and immigrants compared to Arabs and native Israelis and in a study from Southeast Asia, the prevalence rate in the Chinese population was almost twice as high as in the Malay population, though the small number of included patients is a limitation of both studies. [8Delgado J. Sperber A.D. Novack V. Delgado B. Edelman L. Gaspar N. et al.The epidemiology of primary biliary cirrhosis in southern Israel.Isr Med Assoc J. 2005; 7: 717-721PubMed Google Scholar, 9Chong V.H. Telisinghe P.U. Jalihal A. Primary biliary cirrhosis in Brunei Darussalam.Hepatobiliary Pancreat Dis Int. 2010; 9: 622-628PubMed Google Scholar] The data presented by Girard et al. [[1]Girard M. Jannot A.-S. Besnard M. Caude A.H. Biliary atresia: does ethnicity matter?.J Hepatol. 2012; 57: 700-701Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar] exemplify our conclusion that large true population-based epidemiological studies with meticulous case-finding, case-ascertainment, as well as detailed phenotyping (including ancestry) are needed to provide clues for unraveling genetic and environmental risk factors for these diseases. Conflict of interestThe authors declared that they do not have anything to disclose regarding funding or conflict of interest with respect to this manuscript. The authors declared that they do not have anything to disclose regarding funding or conflict of interest with respect to this manuscript.