The etiology of Alzheimer's disease: an epidemiologic point of view.

Putative risk factors for Alzheimer's disease, other than familial aggregation, are: Down's syndrome among relatives, late maternal age, head injury, viral agents, toxic exposures, and immune factors. Current epidemiologic and genetic data are inconclusive, but indicate etiologic heterogeneity. We suggest to investigate separately: autosomal dominant, familial, and sporadic cases.