title: Familial aggregation of Alzheimer's disease and related disorders: a collaborative re-analysis of case-control studies.
abstract: Case-control studies of Alzheimer's disease were re-analysed to examine the association of Alzheimer's disease with family history in first degree relatives of dementia, Down's syndrome and Parkinson's disease. Overall, the relative risk of Alzheimer's disease for those with at least one first degree relative with dementia was 3.5 (95% confidence interval 2.6-4.6). Stratification according to age of onset of Alzheimer's disease showed that the relative risk decreased with increasing onset age. However, among patients with an onset of disease after 80 years, there were still significantly more subjects with one or more first degree relatives with dementia as compared to controls (relative risk 2.6; 95% confidence interval 1.3-5.2). The relative risk of Alzheimer's disease was significantly lower in patients who had one first degree relative with dementia (relative risk 2.6; 95% confidence interval 2.0-3.5) as compared to those who had two or more affected relatives (relative risk 7.5; 95% confidence interval 3.3-16.7). Furthermore, the re-analysis showed a significant association between Alzheimer's disease and family history of Down's syndrome (relative risk 2.7; 95% confidence interval 1.2-5.7), which was strongest in those patients who had a positive family history of dementia. The relative risk of Alzheimer's disease for those with a positive family history of Parkinson's disease was 2.4 (95% confidence interval 1.0-5.8).
authors.affiliation: Department of Epidemiology and Biostatistics, Erasmus University Medical School, Rotterdam, The Netherlands.
authors.forename: C M
authors.initials: CM
authors.lastname: van Duijn
authors.forename: D
authors.initials: D
authors.lastname: Clayton
authors.forename: V
authors.initials: V
authors.lastname: Chandra
authors.forename: L
authors.initials: L
authors.lastname: Fratiglioni
authors.forename: A B
authors.initials: AB
authors.lastname: Graves
authors.forename: A
authors.initials: A
authors.lastname: Heyman
authors.forename: A F
authors.initials: AF
authors.lastname: Jorm
authors.forename: E
authors.initials: E
authors.lastname: Kokmen
authors.forename: K
authors.initials: K
authors.lastname: Kondo
authors.forename: J A
authors.initials: JA
authors.lastname: Mortimer
authors.forename: W A
authors.initials: WA
authors.lastname: Rocca
authors.forename: S L
authors.initials: SL
authors.lastname: Shalat
authors.forename: H
authors.initials: H
authors.lastname: Soininen
authors.forename: A
authors.initials: A
authors.lastname: Hofman
mesh_terms: D000367:Age Factors; D000368:Aged; D000544:Alzheimer Disease / Q000453:epidemiology / Q000235:genetics*; D001315:Australia / Q000453:epidemiology; D016022:Case-Control Studies; D003704:Dementia / Q000453:epidemiology / Q000235:genetics; D004314:Down Syndrome / Q000453:epidemiology / Q000235:genetics; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D015201:Meta-Analysis as Topic; D008875:Middle Aged; D010300:Parkinson Disease / Q000453:epidemiology / Q000235:genetics; D012307:Risk Factors; D014481:United States / Q000453:epidemiology