The San Marino

838 Gut 1995; 36: 838-844 A population based study of Helicobacter pylon' infection in a European country: the San Marino Study. Relations with gastrointestinal diseases Gut: first published as 10.1136/gut.36.6.838 on 1 June 1995. Downloaded from G Gasbarrini, S Pretolani, F Bonvicini, M RA Gatto, E Tonelli, F Megraud, K Mayo, G Ghironzi, G Giulianelli, M Grassi Abstract prostheses (OR= 1.25, 95% CI =1.05 to I Patologia Medica G Gasbarrini Helicobacter pylori is present worldwide 1.49), gastroscopy in the past five years S Pretolani but few large population studies exist (OR=1.50, 95% CI=1*05 to 2.14), peptic F Bonvicini on the epidemiology of the infection. A ulcer in siblings (OR=1.52, 95% CI=1.09 random cross sectional study was per- to gastric cancer in father and Istituto di Igiene, 2.12), University of Bologna, formed of H pylori infection in the adult (OR=1.61, 95% CI=1.02 to 2.52). The Italy population of San Marino, a European association of seropositivity with history M RA Gatto country with high gastric cancer rate, to of ulcer, gastric cancer in family, E Tonelli assess its prevalence and to evaluate its gastroscopy, and H2 antagonists suggests Divisione di Medicina relations with gastrointestinal disease. In that H pylori is an epidemiological Generale, Istituto di 2237 subjects (77% of the initial sample) key factor in the pathogenesis of gastro- Sicurezza Sociale, Republic of H pylorn IgG antibodies were detected duodenal diseases in this area. San Marino with enzyme linked immunosorbent (Gut 1995; 36: 838-844) G Ghironzi assay (ELISA) and immunoblotting. A G Giulianelli questionnaire including questions about Keywords: Helicobacter pylon, population based study, gastrointestinal disease. Laboratoire de occupation, place of birth, and smoking Bact6riologie, USN was given to all subjects. Dyspepsia, Tastet, H6pital cancer in Pellegrin, Universit6 peptic ulcer, and gastric the de Bordeaux, France subjects, relatives, and partners as well as Helicobacter pylori infection is now recognised F Megraud use of drug, dental treatment/prostheses, as one ofthe most common bacterial infections K Mayo and gastrointestinal endoscopies, were in humans.' It is considered the main aetiolog- http://gut.bmj.com/ Instituto de Scienze evaluated by multivariate analysis. ical factor for chronic gastritis2 and also an Sanitarie Applicate, Hpylon prevalence was of 5l1%, increased important determinant for ulcerogenesis,3 University of Pavia, with age from 23% (20-29 years) to 68% especially in the longterm recurrence of duo- Italy M Grassi (¢'70 years), and was higher among denal and gastric ulcer diseases.4-6 H pylori manual workers. H pylon was indepen- infection can persist for years and probably Correspondence to: Professor G Gasbarrini, I dently associated with ulcer (OR= 1'63, decades in most untreated patients2 and sero- Patologia Medica, Policlinico 95% confidence intervals (CI) = 116 to conversion or spontaneous eradication rates on September 28, 2021 by guest. Protected copyright. S Orsola, Via Massarenti 9, 40138 Bologna, Italy. 2.27), H2 antagonists (OR= 1.94, 950/o are low (1% or less) in the general population.7 Accepted for publication CI=1*21 to 3.10), and benzodiazepines Beside the risk ofpeptic ulcer, Hpylori chronic 23 September 1994 (OR=1.57, 95% CI=1*02 to 2.42), dental infection can lead to gastric atrophy, a pre- cursor of gastric cancer.8 This sequence of events has been shown in the early studies performed in Finland and Estonia,9 and chronic gastritis is an important independent risk factor for development of gastric cancer.10 Case control serological studies have clearly shown that the risk for developing gastric adenocarcinoma either in Eastern or Western countries was strongly associated with an H pylori infection already present 10 to 20 years before.'1-13 Gastric cancer rates, how- ever, differ significantly from country to country, from one region to another, and from one generation to the next, suggesting the effect of environmental rather genetic only factors. Hpylori prevalence is higher in areas at high risk for gastric cancer14 and H pylori serum IgG is significantly associated with Rates percentile scale RSM gastric cancer incidence and mortality in different countries.'5 16 To investigate the Minimum Median Maximum epidemiology of H pylon in an entire country of the European Mediterranean area, we Figure 1: Gastric cancer death rates (men, 1980-3) in the Italian region performed a population based study of this Emilia-Romagna. The Republic ofSan Marino (RSM) is situated in the south eastern area ofthis region, where death rates reach the highest numbers (modifiedfrom Regione infection, the San Marino H pylori study. Emilia Romagna Mortality Atlas 1980-83, 1991 edition). The republic of San Marino is located in the San Marino H Pylori study and gastrointestinal diseases 839 northern central part of the Italian peninsula antacids, antibiotics, benzodiazepines, and H2 and is considered the oldest republic of the receptor antagonists). Previous diagnosis of world.'7 San Marino is known to be a country dyspepsia (defined according to Colin-Jones with a high gastric cancer rate,18 19 as is the et al 24), peptic ulcer or gastric cancer, as well adjacent part of Emilia-Romagna in compari- as gastroscopic examinations and present Gut: first published as 10.1136/gut.36.6.838 on 1 June 1995. Downloaded from son with other areas of this region20 (Fig 1). gastrointestinal symptoms in the subject were The San Marino H pylori study was done: (a) recorded. The subjects were also questioned to determine the prevalence of H pylori about the presence of gastrointestinal diseases infection and its relation with age, sex, and in their family (mother, father, brother or environmental factors such as place of birth, sister, husband or wife). The study was occupation, and smoking, (b) to identify any approved by the ethical board of the Istituto di relation of H pylori with use of drugs or with Sicurezza Sociale of San Marino and all previous gastrointestinal endoscopies, history subjects gave informed consent to interviews of dyspepsia, peptic ulcer, and gastric cancer in and blood collection. the subjects of the study as well in their close relatives and partners. Serological examination Serum samples obtained from each subject at Methods the time of interviewing were stored at -70°C. All samples were tested by enzyme Study population linked immunosorbent assay (ELISA) for Between June 1990 and July 1991 a cross evaluation of IgG antibodies to H pylori pro- sectional study was carried out on the adult teins. The antigen used was a centrifuged population (¢ 18 years) living in the nine sonicate of two strains, one from serogroup 1 districts of the Republic of San Marino and the other from serogroup 3 by the Lior (17 000 inhabitants). The Republic of San schema.25 A dilution of 1:100 of each serum Marino was chosen for this study for several was tested in duplicate, as previously specific reasons: (a) the population sampled described.26 The cut offvalue used to define a comprised all the adult inhabitants of a coun- positive serum by ELISA was an optical try with different social classes, professions, density of 0.350, which gives a sensitivity of dietary habits, life styles, and where socio- 95%. All positive samples were subsequently demographic characteristics are very similar tested by immunoblotting. The tests were to those of Western European countries; (b) performed by a BioRad apparatus using whole the population is very stable because of strict cells antigens. An anti-IgG conjugate labelled immigration laws as well as economic incen- with peroxidase was used at a dilution of http://gut.bmj.com/ tives for the residents; (c) in San Marino there 1/500 and 4-chloro-1-naphtol was used as a is a higher incidence of clinically relevant substrate. A sample was considered positive gastroduodenal diseases, such as peptic ulcer for Hpylori IgG antibodies if a 120 000 to 130 and gastric cancer (25 of 10 000 and 8 of 000 molecular weight protein band was 10 000 per year, respectively, in 1990)21 with detected or if five bands among those usually respect to Italy and other European countries. present were visualised. Subjects with a Subjects for the study were selected from the positive immunoblot test were considered to on September 28, 2021 by guest. Protected copyright. National Register of residents in San Marino have Hpylori infection. at January 1990, after a random stratified sampling with proportional allocation by age, sex, and district. Estimated prevalence of Statistical analysis antibodies by age reported in a previous The data were analysed by a x2 test (Mantel- study22 were used to determine sample size.23 Haenszel) and logistic regression using the Data on gastric cancer incidence during SPSS-X statistical package.27 The x2 test was the period 1988 to 93 were obtained from the used to examine the association between files of the endoscopy unit of the department H pylori infection and the presence of several of internal medicine of the San Marino variables in a monovariate analysis and to Hospital. choose the relevant variables to be used in mul- Six months before starting the study, mass tivariate analysis. Logistic regression was used media were used to inform the San Marino to evaluate the relation between each indepen- population about the object of the study. A dent variable of the study and the frequency of letter explaining the purpose of the study was H pylori infection with adjustment for other sent to all the enrollees. A telephone call was variables. made later to each subject to organise the medical interview at the division of internal medicine of the Istituto di Sicurezza Sociale of TABLE I Study population by age and sex (San Maino San Marino.

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