Javier Santabárbara1, Ana Cristina Gracía-Rebled2, Raúl López-Antón3, Concepción Tomás2, Elena Lobo1, Guillermo Marcos1, Antonio Lobo4. 1. 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. 2. Departamento de Fisiatría y Enfermería, Universidad de Zaragoza, C/Domingo Miral s/n, 50009 Zaragoza, Spain. 3. 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. Electronic address: rlanton@unizar.es. 4. 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.
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.
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.