Early-onset Alzheimer's disease in Scotland: environmental and familial factors

Background Alzheimer's disease (AD) is a common, complex, age-related disor der in which both genetic and environmental factors are important. Aims To integrate recent studies on genetic and environmental factors in AD into a multi-factorial disease model. Method Disease models to explain gene-environment interaction in cardiovasc ular disease are related to observations on AD. Results Informative, community based studies on the genetic epidemiology of AD are rare. Putative risk factors from the Scottish studies include incre ased paternal age in AD men and coal mining as paternal occupation in both AD and vascular dementia. Migration effects suggest that environmental fact ors in high incidence AD areas are important during adult life. Conclusions The studies summarised do not provide sufficient data to suppor t a single comprehensive disease model of gene-environment interaction in A D. Future studies will require very large ( greater than or equal to 600) s ample sizes, molecular genetic analysis, and environmental data that span n eurodevelopment and the period between disease onset and appearance of clin ical symptoms. Declaration of interest The author has received consultancy fees from Brist ol-Myers Squibb, Novartis, Esai, Hoechst Marion Roussel and Bayer. He was p rincipal UK investigator in clinical trials of rivastigmine.