Environmental pesticide exposure as a risk factor for Alzheimer's disease:A case-control study

The aim of this study was to evaluate the influence of pesticide exposure o n the development of Alzheimer's disease (AD), taking into account the pote ntially confounding factors (genetic, occupational exposure, and sociodemog raphic). The 1924 study participants (> 70 years old) were randomly selecte d in the Saguenay-Lac Saint-Jean region (Quebec, Canada). The AD diagnosis was established in three steps according to recognized criteria. Sixty-eigh t cases were paired with a nondemented control for age (+/-2 years) and sex . Structured questionnaires addressed to subjects and proxy respondents all owed a description of the sociodemographic characteristics, lifestyle chara cteristics, and residential, occupational, familial, and medical histories. Assessment of environmental exposure to pesticides was based on residentia l histories and the agriculture census histories of Statistics Canada (1971 -1991) for herbicide and insecticide spraying in the area. Statistical anal yses were performed with a logistic regression, adjusting for potential con founding factors. The results failed to show a significant risk of AD with an exposure to herbicides, insecticides, and pesticides. However, future in vestigations are needed to establish more precisely the identification, mea surement, mobility, and bioavailability of neurotoxic pesticide residues in relation to AD. (C) 2001 Academic Press.