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The effect of occupation type on risk of Alzheimer’s disease in men and women

  • Author Footnotes
    1 These two authors contributed equally to this work.
    Javier Santabárbara
    Footnotes
    1 These two authors contributed equally to this work.
    Affiliations
    Departamento de Medicina Preventiva y Salud Pública, Universidad de Zaragoza, C/Domingo Miral s/n, 50009 Zaragoza, Spain

    Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain

    Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Ministry of Science and Innovation, Madrid, Spain
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  • Author Footnotes
    1 These two authors contributed equally to this work.
    Ana Cristina Gracía-Rebled
    Footnotes
    1 These two authors contributed equally to this work.
    Affiliations
    Departamento de Fisiatría y Enfermería, Universidad de Zaragoza, C/Domingo Miral s/n, 50009 Zaragoza, Spain
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  • Raúl López-Antón
    Correspondence
    Corresponding author at: Departamento de Psicología y Sociología, Universidad de Zaragoza, Calle Doctor Cerrada 1-5, 50009 Zaragoza, Spain.
    Affiliations
    Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain

    Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Ministry of Science and Innovation, Madrid, Spain

    Departamento de Psicología y Sociología, Universidad de Zaragoza, C/Doctor Cerrada 1-5, 50009 Zaragoza, Spain
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  • Concepción Tomás
    Affiliations
    Departamento de Fisiatría y Enfermería, Universidad de Zaragoza, C/Domingo Miral s/n, 50009 Zaragoza, Spain
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  • Elena Lobo
    Affiliations
    Departamento de Medicina Preventiva y Salud Pública, Universidad de Zaragoza, C/Domingo Miral s/n, 50009 Zaragoza, Spain

    Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain

    Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Ministry of Science and Innovation, Madrid, Spain
    Search for articles by this author
  • Guillermo Marcos
    Affiliations
    Departamento de Medicina Preventiva y Salud Pública, Universidad de Zaragoza, C/Domingo Miral s/n, 50009 Zaragoza, Spain

    Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain

    Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Ministry of Science and Innovation, Madrid, Spain
    Search for articles by this author
  • Antonio Lobo
    Affiliations
    Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain

    Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Ministry of Science and Innovation, Madrid, Spain

    Servicio de Psiquiatría, Hospital Clínico Universitario, Avda. San Juan Bosco 15, 50009 Zaragoza, Spain

    Departamento de Psiquiatría, Universidad de Zaragoza, C/Domingo Miral s/n, 50009 Zaragoza, Spain
    Search for articles by this author
  • Author Footnotes
    1 These two authors contributed equally to this work.

      Highlights

      • In an occupational analysis, the “farmer” category had a lower risk of Alzheimer’s disease among both men and women.
      • Men “farmers” had a 66% lower risk of AD than the “white collar” and women “farmers” had a 45% lower risk than “homemakers”.
      • The effect size for this association is considered large (Cohen’s d = 0.84) in men and medium (Cohen’s d = 0.46) in women.

      Abstract

      Objectives

      To examine the association between the principal lifetime occupation and the incidence of Alzheimer’s disease (AD) in men and women in a southern European population aged 55 years or more.

      Study design

      A community-dwelling sample of 3883 dementia-free individuals aged 55 years or over was classified according the Spanish National Classification of Occupations (CNO-11) and the International Standard Classification of Occupations (ISCO-08) in a four-wave epidemiological study. Medical and psychiatric histories were collected using standardized instruments, including the Mini-Mental Status Examination (MMSE), the History and Aetiology Schedule (HAS), the Geriatric Mental State-AGECAT, and a risk factor Questionnaire. Cases of AD were diagnosed according to DSM-IV criteria. Cox regression models were performed, stratified by sex.

      Main outcome measures

      Cases of AD according to the main occupation and sex.

      Results

      In men, compared with the “white collar” category, the risk of AD in “farmers” was 66% times lower, after controlling for potential confounding factors (HR: 0.34; 95% CI: 0.08–1.33). It did not reach statistical significance but the magnitude was large (Cohen’s d = 0.84). In women, “farmers” had almost 50% less risk of AD after controlling for all potential confounding factors (HR: 0.55; 95% CI: 0.17–1.78), compared with homemakers, but with a medium effect size (Cohen’s d = 0.46).

      Conclusions

      Men and women farmers had a lower risk of AD, reinforcing the importance of lifetime occupation in the risk of AD at older ages. These results could suggest some environmental hypotheses.

      Keywords

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