The Prevalence and Incidence of Dementia Due to Alzheimer's Disease: a Systematic Review and Meta-Analysis.
BACKGROUND
Updated information on the epidemiology of dementia due to Alzheimer's disease (AD) is needed to ensure that adequate resources are available to meet current and future healthcare needs. We conducted a systematic review and meta-analysis of the incidence and prevalence of AD.


METHODS
The MEDLINE and EMBASE databases were searched from 1985 to 2012, as well as the reference lists of selected articles. Included articles had to provide an original population-based estimate for the incidence and/or prevalence of AD. Two individuals independently performed abstract and full-text reviews, data extraction and quality assessments. Random-effects models were employed to generate pooled estimates stratified by age, sex, diagnostic criteria, location (i.e., continent) and time (i.e., when the study was done).


RESULTS
Of 16,066 abstracts screened, 707 articles were selected for full-text review. A total of 119 studies met the inclusion criteria. In community settings, the overall point prevalence of dementia due to AD among individuals 60+ was 40.2 per 1000 persons (CI95%: 29.1-55.6), and pooled annual period prevalence was 30.4 per 1000 persons (CI95%: 15.6-59.1). In community settings, the overall pooled annual incidence proportion of dementia due to AD among individuals 60+ was 34.1 per 1000 persons (CI95%: 16.4-70.9), and the incidence rate was 15.8 per 1000 person-years (CI95%: 12.9-19.4). Estimates varied significantly with age, diagnostic criteria used and location (i.e., continent).


CONCLUSIONS
The burden of AD dementia is substantial. Significant gaps in our understanding of its epidemiology were identified, even in a high-income country such as Canada. Future studies should assess the impact of using such newer clinical diagnostic criteria for AD dementia such as those of the National Institute on Aging-Alzheimer's Association and/or incorporate validated biomarkers to confirm the presence of Alzheimer pathology to produce more precise estimates of the global burden of AD.
1Department of Community Health Sciences,University of Calgary,Calgary,Alberta,Canada.
Kirsten M
KM
Fiest
1Department of Community Health Sciences,University of Calgary,Calgary,Alberta,Canada.
Jodie I
JI
Roberts
1Department of Community Health Sciences,University of Calgary,Calgary,Alberta,Canada.
Colleen J
CJ
Maxwell
7Brenda Strafford Chair in Geriatric Medicine,University of Calgary,Calgary,Alberta,Canada.
David B
DB
Hogan
1Department of Community Health Sciences,University of Calgary,Calgary,Alberta,Canada.
Eric E
EE
Smith
1Department of Community Health Sciences,University of Calgary,Calgary,Alberta,Canada.
Alexandra
A
Frolkis
8Department of Medicine,Cumming School of Medicine,University of Calgary,Calgary,Alberta,Canada.
Adrienne
A
Cohen
9Department of Medicine,University of Saskatchewan,Saskatoon,Saskatchewan,Canada.
Andrew
A
Kirk
3Hotchkiss Brain Institute,University of Calgary,Calgary,Alberta,Canada.
Dawn
D
Pearson
1Department of Community Health Sciences,University of Calgary,Calgary,Alberta,Canada.
Tamara
T
Pringsheim
Andres
A
Venegas-Torres
1Department of Community Health Sciences,University of Calgary,Calgary,Alberta,Canada.
Nathalie
N
Jetté
D000544:Alzheimer Disease / Q000150:complications* / Q000453:epidemiology; D016206:Databases, Bibliographic / Q000706:statistics & numerical data; D003704:Dementia / Q000453:epidemiology* / Q000209:etiology*; D006801:Humans; D015994:Incidence; D015995:Prevalence; D012111:Residence Characteristics / Q000706:statistics & numerical data
Alzheimer’s; dementia; meta-analysis; systematic review