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The seroprevalence of Helicobacter pylori in an Irish university student population
Journal of Infection (2004) 48, 283–284
www.elsevierhealth.com/journals/jinf
Letter to the Editor The seroprevalence of Helicobacter pylori in an Irish university student population Sir, Helicobacter pylori plays a crucial role in peptic ulcer disease, with several studies showing that up to 95% of duodenal ulcers and 80% of gastric ulcers are associated with H. pylori infection. H. pylori has also been classified as a definite carcinogen. Numerous studies have reported worldwide variations in prevalence of the bacterium. Although of great interest epidemiologically, detailed data on the prevalence of the bacterium in the younger population in Western European countries, particularly Ireland, remain relatively scarce. Accordingly, we designed a study to evaluate the seroprevalence of H. pylori in an Irish university student population. Volunteer students were randomly selected in The University of Dublin, Trinity College. A blood sample was taken from each subject for evaluation of immunoglobulin G antibody to H. pylori. ELISA was carried out using the Launch Premier (Meridian Diagnostics) qualitative enzyme immunoassay kit. Of the total 170 volunteers, 104 were Irish, 38 Malaysian, 4 African, 15 North American, 5 British, 3 Australian, 1 Spanish. Medical students represented 62% of the total number. Fourteen percent were Science students and 9% were Dental students. The seroprevalence of H. pylori was surprisingly high at 51.8%, the median age in the population being 20 years. Indeed, the seropositivity in Irish students alone was as high as 59%. A previous communitybased study in Ireland found a prevalence of infection of 29% in 18 – 30 years olds.1 Rothenbacher et al. studying a population of outpatients attending a general practitioner in Southern Germany found a prevalence of H. pylori infection in the 15 – 29 years age group of 30.8%.2 Another German study on blood donors showed a seroprevalence of about 21% by the age of 21 years.3 In a study on an Anglo-Celtic population in Melbourne, Australia, the H. pylori seroprevalence in the 20 – 30 years age group was 18%.4 The high prevalence in our study cannot be explained on the basis of a
heterogeneous study population including students from non-western countries. As stated, 59% of Irish students were seropositive in comparison to only 29% of Malaysian students. In fact, this seropositivity figure in Irish students approaches the figures in studies on non-western adult populations. A study on an asymptomatic Turkish population found seropositivity rates of 62.6% in the 20 – 29 years age group.5 This latter study concluded that the high prevalence and early acquisition of H. pylori infection might in part be related to traditional living conditions and socio-economic status in Turkey. A similar study was carried out in Lithuanian medical students in which prevalence of seropositivity detected was 51.7%.6 There is evidence that H. pylori infection is more prevalent in doctors, especially gastroenterologists and endoscopy personnel.7 Sixty-two percent of our study group were medical students. It is possible that this might explain in some way the unusually high seroprevalence in our study but this is relatively unlikely in that the majority of medical students in this study were pre-clinical students who should be at not greater risk of acquiring H. pylori infection than the average age matched individual. It is interesting to note that the highest seroprevalence (66%) was among the dental students. Perhaps earlier exposure to patients in dentistry may be a factor. In conclusion, we found a surprisingly high seroprevalence for H. pylori in our young university study population. The rate was especially high in Irish students (59%). This figure is 2 – 3 times the prevalence reported in this age group in other studies in Western Europe, or groups of European descent in Australia for example. The high seroprevalence of H. pylori in this young population may have important clinical and economic implications. Understanding the epidemiology of H. pylori infection will allow us to implement better strategies for eradication or possibly vaccination, to develop public health measures, and to assess for example the risk of developing gastric cancer in relation to H. pylori infection. Sincerely,
0163-4453/$30.00 Q 2003 The British Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jinf.2003.10.003
284
References 1. Buckley MJ, O’Shea J, Grace A, et al. A community based study of the epidemiology of H. pylori infection and associated asymptomatic gastroduodenal pathology. Eur J Gastroenterol Hepatol 1998;10:375—379. 2. Rothenbacher D, Bode G, Winz T, Berg G, Adler G, Brenner H. Helicobacter pylori in out-patients of a general practitioner: prevalence and determinants of current infection. Epidemiol Infect 1997;119:151—157. 3. Breuer T, Sudhop T, Hoch J, Sauerbruch T, Malfertheiner P. Prevalence of and risk factors for H. pylori infection in the western part of Germany. Eur J Gastroenterol Hepatol 1996; 8:47—52. 4. Lin SK, Lambert JR, Nicholson L, Lukito W, Wahlqvist M. Prevalence of H. pylori in a representative anglo-celtic population of urban Melbourne. J Gastroenterol Hepatol 1998;13:505—510. 5. Us D, Hascelik G. Seroprevalence of H. pylori infection in an asymptomatic Turkish population. J Infect 1998;37:148—150. 6. Kupcinskas L, Kiudelis G. H. pylori infection in Lithuanian
*Corresponding author. Address: Division of Gastroenterology, Vancouver General Hospital, 100–2647 Willow Street, Vancouver V5Z 3P1, Canada. Tel.: þ 1-604-875-5244; fax: þ1-604-875-5447.
Letter to the Editor
medical students and its relation to dyspepsia. Gut 1997; 41(Suppl. 3):A-104. 7. Lin SK, Lambert JR, Schembri MA, Nicholson L, Korman M. Helicobacter pylori prevalence in endoscopy and medical staff. J Gastroenterol Hepatol 1994;9:319—324.
Katherine M. Sheehana,c, Michael F. Byrneb,*, Frank E. Murrayb a Department of Pathology, Beaumont Hospital, Dublin, Ireland b Department of Gastroenterology, Beaumont Hospital, Dublin, Ireland c Department of Physiology, Trinity College, Dublin, Ireland E-mail address: [email protected] Accepted 4 October 2003
www.elsevierhealth.com/journals/jinf
Letter to the Editor The seroprevalence of Helicobacter pylori in an Irish university student population Sir, Helicobacter pylori plays a crucial role in peptic ulcer disease, with several studies showing that up to 95% of duodenal ulcers and 80% of gastric ulcers are associated with H. pylori infection. H. pylori has also been classified as a definite carcinogen. Numerous studies have reported worldwide variations in prevalence of the bacterium. Although of great interest epidemiologically, detailed data on the prevalence of the bacterium in the younger population in Western European countries, particularly Ireland, remain relatively scarce. Accordingly, we designed a study to evaluate the seroprevalence of H. pylori in an Irish university student population. Volunteer students were randomly selected in The University of Dublin, Trinity College. A blood sample was taken from each subject for evaluation of immunoglobulin G antibody to H. pylori. ELISA was carried out using the Launch Premier (Meridian Diagnostics) qualitative enzyme immunoassay kit. Of the total 170 volunteers, 104 were Irish, 38 Malaysian, 4 African, 15 North American, 5 British, 3 Australian, 1 Spanish. Medical students represented 62% of the total number. Fourteen percent were Science students and 9% were Dental students. The seroprevalence of H. pylori was surprisingly high at 51.8%, the median age in the population being 20 years. Indeed, the seropositivity in Irish students alone was as high as 59%. A previous communitybased study in Ireland found a prevalence of infection of 29% in 18 – 30 years olds.1 Rothenbacher et al. studying a population of outpatients attending a general practitioner in Southern Germany found a prevalence of H. pylori infection in the 15 – 29 years age group of 30.8%.2 Another German study on blood donors showed a seroprevalence of about 21% by the age of 21 years.3 In a study on an Anglo-Celtic population in Melbourne, Australia, the H. pylori seroprevalence in the 20 – 30 years age group was 18%.4 The high prevalence in our study cannot be explained on the basis of a
heterogeneous study population including students from non-western countries. As stated, 59% of Irish students were seropositive in comparison to only 29% of Malaysian students. In fact, this seropositivity figure in Irish students approaches the figures in studies on non-western adult populations. A study on an asymptomatic Turkish population found seropositivity rates of 62.6% in the 20 – 29 years age group.5 This latter study concluded that the high prevalence and early acquisition of H. pylori infection might in part be related to traditional living conditions and socio-economic status in Turkey. A similar study was carried out in Lithuanian medical students in which prevalence of seropositivity detected was 51.7%.6 There is evidence that H. pylori infection is more prevalent in doctors, especially gastroenterologists and endoscopy personnel.7 Sixty-two percent of our study group were medical students. It is possible that this might explain in some way the unusually high seroprevalence in our study but this is relatively unlikely in that the majority of medical students in this study were pre-clinical students who should be at not greater risk of acquiring H. pylori infection than the average age matched individual. It is interesting to note that the highest seroprevalence (66%) was among the dental students. Perhaps earlier exposure to patients in dentistry may be a factor. In conclusion, we found a surprisingly high seroprevalence for H. pylori in our young university study population. The rate was especially high in Irish students (59%). This figure is 2 – 3 times the prevalence reported in this age group in other studies in Western Europe, or groups of European descent in Australia for example. The high seroprevalence of H. pylori in this young population may have important clinical and economic implications. Understanding the epidemiology of H. pylori infection will allow us to implement better strategies for eradication or possibly vaccination, to develop public health measures, and to assess for example the risk of developing gastric cancer in relation to H. pylori infection. Sincerely,
0163-4453/$30.00 Q 2003 The British Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jinf.2003.10.003
284
References 1. Buckley MJ, O’Shea J, Grace A, et al. A community based study of the epidemiology of H. pylori infection and associated asymptomatic gastroduodenal pathology. Eur J Gastroenterol Hepatol 1998;10:375—379. 2. Rothenbacher D, Bode G, Winz T, Berg G, Adler G, Brenner H. Helicobacter pylori in out-patients of a general practitioner: prevalence and determinants of current infection. Epidemiol Infect 1997;119:151—157. 3. Breuer T, Sudhop T, Hoch J, Sauerbruch T, Malfertheiner P. Prevalence of and risk factors for H. pylori infection in the western part of Germany. Eur J Gastroenterol Hepatol 1996; 8:47—52. 4. Lin SK, Lambert JR, Nicholson L, Lukito W, Wahlqvist M. Prevalence of H. pylori in a representative anglo-celtic population of urban Melbourne. J Gastroenterol Hepatol 1998;13:505—510. 5. Us D, Hascelik G. Seroprevalence of H. pylori infection in an asymptomatic Turkish population. J Infect 1998;37:148—150. 6. Kupcinskas L, Kiudelis G. H. pylori infection in Lithuanian
*Corresponding author. Address: Division of Gastroenterology, Vancouver General Hospital, 100–2647 Willow Street, Vancouver V5Z 3P1, Canada. Tel.: þ 1-604-875-5244; fax: þ1-604-875-5447.
Letter to the Editor
medical students and its relation to dyspepsia. Gut 1997; 41(Suppl. 3):A-104. 7. Lin SK, Lambert JR, Schembri MA, Nicholson L, Korman M. Helicobacter pylori prevalence in endoscopy and medical staff. J Gastroenterol Hepatol 1994;9:319—324.
Katherine M. Sheehana,c, Michael F. Byrneb,*, Frank E. Murrayb a Department of Pathology, Beaumont Hospital, Dublin, Ireland b Department of Gastroenterology, Beaumont Hospital, Dublin, Ireland c Department of Physiology, Trinity College, Dublin, Ireland E-mail address: [email protected] Accepted 4 October 2003