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Sociodemographic Determinants of Prevalence and Incidence of Helicobacter pylori Infection in Portuguese Adults

Authors

  • Joana Bastos,

    1. Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal
    2. Institute of Public Health of the University of Porto (ISPUP), Porto, Portugal
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  • Bárbara Peleteiro,

    1. Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal
    2. Institute of Public Health of the University of Porto (ISPUP), Porto, Portugal
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  • Rita Barros,

    1. Institute of Molecular Pathology and Immunology (IPATIMUP), University of Porto, Porto, Portugal
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  • Luís Alves,

    1. Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal
    2. Institute of Public Health of the University of Porto (ISPUP), Porto, Portugal
    3. St André de Canidelo Family Health Unit, Vila Nova de Gaia, Portugal
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  • Milton Severo,

    1. Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal
    2. Institute of Public Health of the University of Porto (ISPUP), Porto, Portugal
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  • Maria de Fátima Pina,

    1. Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal
    2. Institute of Public Health of the University of Porto (ISPUP), Porto, Portugal
    3. Biomedical Engineering Institute (INEB), University of Porto, Porto, Portugal
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  • Hugo Pinto,

    1. Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal
    2. Institute of Public Health of the University of Porto (ISPUP), Porto, Portugal
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  • Sandra Carvalho,

    1. Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal
    2. Institute of Public Health of the University of Porto (ISPUP), Porto, Portugal
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  • Ana Marinho,

    1. Department of Clinical Pathology, Centro Hospitalar de São João, Porto, Portugal
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  • João T. Guimarães,

    1. Institute of Public Health of the University of Porto (ISPUP), Porto, Portugal
    2. Department of Clinical Pathology, Centro Hospitalar de São João, Porto, Portugal
    3. Department of Biochemistry, University of Porto Medical School, Porto, Portugal
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  • Ana Azevedo,

    1. Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal
    2. Institute of Public Health of the University of Porto (ISPUP), Porto, Portugal
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  • Carlo La Vecchia,

    1. Department of Epidemiology, IRCCS-Istituto di Ricerche Farmacologiche ‘Mario Negri’, Milan, Italy
    2. Department of Medical Sciences and Public Health, Università degli Studi di Milano, Milan, Italy
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  • Henrique Barros,

    1. Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal
    2. Institute of Public Health of the University of Porto (ISPUP), Porto, Portugal
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  • Nuno Lunet

    Corresponding author
    1. Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal
    2. Institute of Public Health of the University of Porto (ISPUP), Porto, Portugal
    • Reprint requests to: Nuno Lunet, Departamento de Epidemiologia Clínica, Medicina Preditiva e Saúde Pública, Faculdade de Medicina da Universidade do Porto, Al. Prof. Hernâni Monteiro, Porto 4200-319, Portugal. E-mail: nlunet@med.up.pt

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Abstract

Background

Understanding the determinants of Helicobacter pylori infection in adults is essential to predict the burden of H. pylori-related diseases. We aimed to estimate the prevalence and incidence of H. pylori infection and to identify its major sociodemographic correlates in an urban population from the North of Portugal.

Material and Methods

A representative sample of noninstitutionalized adult inhabitants of Porto (n = 2067) was evaluated by ELISA (IgG) and a subsample (n = 412) was tested by Western Blot to assess infection with CagA-positive strains. Modified Poisson and Poisson regression models were used to estimate crude and sex-, age-, and education-adjusted prevalence ratios (PR) and incidence rate ratios (RR), respectively.

Results

The prevalence of H. pylori infection was 84.2% [95% confidence interval (95%CI): 82.4–86.1]. It increased across age-groups in the more educated subjects, (18–30 years: 72.6%; ≥71 years: 88.1%; p for trend <0.001) and decreased with education in the younger (≤4 schooling years: 100.0%; ≥10 schooling years: 72.6%; p for trend <0.001). Living in a more deprived neighborhood was associated with a higher prevalence of infection, only in the younger (PR = 1.20, 95%CI: 1.03–1.38) and more educated participants (PR = 1.15, 95%CI: 1.03–1.29). Among the infected, the proportion with CagA-positive strains was 61.7% (95%CI: 56.6–66.9). The incidence rate was 3.6/100 person-years (median follow-up: 3 years; 95%CI: 2.1–6.2), lower among the more educated (≥10 vs ≤9: RR = 0.25, 95%CI: 0.06–0.96). The seroreversion rate was 1.0/100 person-years (95%CI: 0.6–1.7).

Conclusions

The prevalence of infection among adults is still very high in Portugal, suggesting that stomach cancer rates will remain high over the next few decades.

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