title: Alzheimer's disease and coffee: a quantitative review.
abstract: OBJECTIVE
  To estimate the pooled risk of coffee consumption for Alzheimer's disease (AD).
  
  
  METHODS
  We have reviewed all observational studies that evaluated the association between AD risk and coffee consumption. Four studies were identified: two case-control studies and two cohorts. These studies were carried out between 1990 and 2002.
  
  
  RESULTS
  There was an obvious protective effect of coffee consumption in the pooled estimate [risk estimate: 0.73 (95% confidence interval: 0.58-0.92)]. However, the homogeneity test was highly significant (p<0.01), indicating heterogeneity across the pooled studies. Pooled analysis applying the random effect model was 0.79 with 95% confidence interval overlapping unity (95% confidence interval: 0.46-1.36). Three studies assessed coffee consumption by interview questionnaire. The risk of AD in coffee consumers versus non-consumers in studies that used interview questionnaire had a pooled risk estimate of 0.70 with 95% confidence interval 0.55-0.90.
  
  
  CONCLUSIONS
  Although our pooled estimates show that coffee consumption is inversely associated with the risk of AD, the four studies had heterogeneous methodologies and results. Further prospective studies evaluating the association between coffee consumption and AD are strongly needed.
authors.affiliation: Department of Preventive Medicine and Public Health, Faculty of Medicine, University of Cordoba, Cordoba, Spain.
authors.forename: José Luis
authors.initials: JL
authors.lastname: Barranco Quintana
authors.forename: Mohamed Farouk
authors.initials: MF
authors.lastname: Allam
authors.forename: Amparo
authors.initials: A
authors.lastname: Serrano Del Castillo
authors.forename: Rafael
authors.initials: R
authors.lastname: Fernández-Crehuet Navajas
mesh_terms: D000544:Alzheimer Disease / Q000188:drug therapy / Q000209:etiology* / Q000517:prevention & control*; D016022:Case-Control Studies; D003069:Coffee; D015331:Cohort Studies; D005247:Feeding Behavior / Q000502:physiology*; D006801:Humans; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D003069:Coffee