title: Population studies of sporadic cerebral amyloid angiopathy and dementia: a systematic review.
abstract: BACKGROUND
  Deposition of amyloid-beta (Abeta) in vessel walls of the brain as cerebral amyloid angiopathy (CAA) could be a major factor in the pathogenesis of dementia. Here we investigate the relationship between dementia and the prevalence of CAA in older populations. We searched the literature for prospective population-based epidemiological clinicopathological studies, free of the biases of other sampling techniques, which were used as a comparison.
  
  
  METHODS
  To identify population-based studies assessing CAA and dementia, a previous systematic review of population-based clinicopathological studies of ageing and dementia was employed. To identify selected-sample studies, PsychInfo (1806-April Week 3 2008), OVID MEDLINE (1950-April Week 2 2008) and Pubmed (searched 21 April 2008) databases were searched using the term "amyloid angiopathy". These databases were also employed to search for any population-based studies not included in the previous systematic review. Studies were included if they reported the prevalence of CAA relative to a dementia classification (clinical or neuropathological).
  
  
  RESULTS
  Four population-based studies were identified. They showed that on average 55-59% of those with dementia displayed CAA (of any severity) compared to 28-38% of the non-demented. 37-43% of the demented displayed severe CAA in contrast to 7-24% of the non-demented. There was no overlap in the range of these averages and they were less variable and lower than those reported in 38 selected sample studies (demented v non-demented: 32-100 v 0-77% regardless of severity; 0-50 v 0-11% for severe only).
  
  
  CONCLUSIONS
  CAA prevalence in populations is consistently higher in the demented as compared to the non-demented. This supports a significant role for CAA in the pathogenesis of dementia.
authors.affiliation: Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK. hk323@medschl.cam.ac.uk
authors.forename: Hannah A D
authors.initials: HA
authors.lastname: Keage
authors.forename: Roxanna O
authors.initials: RO
authors.lastname: Carare
authors.forename: Robert P
authors.initials: RP
authors.lastname: Friedland
authors.forename: Paul G
authors.initials: PG
authors.lastname: Ince
authors.forename: Seth
authors.initials: S
authors.lastname: Love
authors.forename: James A
authors.initials: JA
authors.lastname: Nicoll
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Wharton
authors.forename: Roy O
authors.initials: RO
authors.lastname: Weller
authors.forename: Carol
authors.initials: C
authors.lastname: Brayne
mesh_terms: D000369:Aged, 80 and over; D000375:Aging; D001057:Apolipoproteins E / Q000235:genetics; D001921:Brain / Q000473:pathology*; D016657:Cerebral Amyloid Angiopathy / Q000150:complications / Q000453:epidemiology* / Q000473:pathology; D003704:Dementia / Q000150:complications / Q000453:epidemiology* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D012307:Risk Factors
chemical_list: D001057:Apolipoproteins E