title: Prevalence of Helicobacter pylori infection and associated factors among adults in Southern Brazil: a population-based cross-sectional study.
abstract: BACKGROUND
  Helicobacter pylori (Hp) infection is associated with several upper gastrointestinal disorders. Local data on the epidemiology of the infection are scarce in Brazil. The purpose of this study is to measure the prevalence rate and to explore the associated factors among the adult population living in Pelotas, a southern Brazilian city.
  
  
  METHODS
  This was a population-based cross-sectional study. Through a multi-stage sampling method all individuals 20 years and over living at the selected households at the urban area of the city were interviewed regarding past and current socio-economic indicators; demographic characteristics; nutritional and behavioural habits; and history of upper gastrointestinal symptoms.Hp infection was ascertained through the 13C-UBT. Due to the high prevalence, data were analysed through robust Poisson regression. All analyses took into account the family clustering of the data.
  
  
  RESULTS
  Among 563 eligible individuals, 363 agreed to perform the 13C-UBT (refusal rate of 35.5%). Refusals were associated with female sex, consumption of mate drinking, and presence of upper gastrointestinal symptoms. The prevalence rate of H. pylori infection was 63.4% (95%CI 59.3%-69.3%). In crude analyses, prevalence was associated with increasing age, non-white skin colour, lower current family income, lower education level, higher size of the family, low socio-economic conditions in childhood, higher number of siblings and attendance to day-care centres in childhood, and presence of dyspeptic symptoms. In adjusted analysis the level of education of the father was inversely associated with the infection, whereas number of siblings and attendance to day-care centre in childhood were directly associated with it. Non-white skin colour remained significantly associated with increased prevalence even after allowing for past and current socio-economic characteristics, age and sex. Compared to non-symptomatic individuals, those reporting dyspeptic symptoms presented a higher prevalence of the infection even after allowing for current and past socio-economic conditions, ethnicity, age, and sex.
  
  
  CONCLUSIONS
  Hp infection is as common among adults in southern Brazil as it is in other developing countries. Socio-economic conditions in childhood besides ethnicity and presence of dyspeptic symptoms were the factors significantly associated with the infection.
authors.affiliation: Department of Social Medicine, Faculty of Medicine, Federal University of Pelotas, Pelotas, Brazil. inasantos@uol.com.br
authors.forename: Ina S
authors.initials: IS
authors.lastname: Santos
authors.forename: Jose
authors.initials: J
authors.lastname: Boccio
authors.forename: Ari S
authors.initials: AS
authors.lastname: Santos
authors.forename: Neiva C J
authors.initials: NC
authors.lastname: Valle
authors.forename: Camila S
authors.initials: CS
authors.lastname: Halal
authors.forename: Marta Colvara
authors.initials: MC
authors.lastname: Bachilli
authors.forename: Ricardo D
authors.initials: RD
authors.lastname: Lopes
mesh_terms: D000328:Adult; D001938:Brazil / Q000453:epidemiology; D001944:Breath Tests; D002247:Carbon Isotopes / Q000032:analysis; D003430:Cross-Sectional Studies; D005191:Family Characteristics; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D016481:Helicobacter Infections / Q000175:diagnosis / Q000453:epidemiology*; D016480:Helicobacter pylori / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016012:Poisson Distribution; D015995:Prevalence; D012959:Socioeconomic Factors; D014504:Urban Health / Q000706:statistics & numerical data*
chemical_list: D002247:Carbon Isotopes