All AD cases were ascertained by neurologists from Bordeaux, Dijon, Lille, Montpelier, Paris, and Rouen, with clinical diagnosis of probable AD established according to the DSM-III-R and National Institute of Neurological and Communication Disorders and Stroke-Alzheimer’s Disease and Related Disorders Association (NINCDS-ADRDA) criteria51,52. Controls were recruited from Lille, Rouen, Nantes and from the 3C Study51. This cohort is a population-based, prospective study of the relationship between vascular factors and dementia. It has been carried out in three French cities: Bordeaux (southwest France), Montpelier (southeast France) and Dijon (central eastern France). A sample of non-institutionalized, subjects over 65 years was randomly selected from the electoral rolls of each city. Between January 1999 and March 2001, 9,686 subjects meeting the inclusion criteria agreed to participate. Following recruitment, 392 subjects withdrew from the study. Thus, 9,294 subjects were finally included in the study (2,104 in Bordeaux, 4,931 in Dijon and 2,259 in Montpellier). At 8 years of follow up, 664 individuals suffered from AD with 167 prevalent and 497 incident cases. The other individuals were considered as controls. 9863 DNA samples that passed
