Prevalence of Cerebral Amyloid Pathology in Persons Without Dementia A Meta-analysis

Willemijn J. Jansen*, Rik Ossenkoppele, Dirk L. Knol, Betty M. Tijms, Philip Scheltens, Frans R. J. Verhey, Pieter Jelle Visser

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


IMPORTANCE Cerebral amyloid-beta aggregation is an early pathological event in Alzheimer disease (AD), starting decades before dementia onset. Estimates of the prevalence of amyloid pathology in persons without dementia are needed to understand the development of AD and to design prevention studies. OBJECTIVE To use individual participant data meta-analysis to estimate the prevalence of amyloid pathology as measured with biomarkers in participants with normal cognition, subjective cognitive impairment (SCI), or mild cognitive impairment (MCI). DATA SOURCES Relevant biomarker studies identified by searching studies published before April 2015 using the MEDLINE and Web of Science databases and through personal communication with investigators. STUDY SELECTION Studies were included if they provided individual participant data for participants without dementia and used an a priori defined cutoff for amyloid positivity. DATA EXTRACTION AND SYNTHESIS Individual records were provided for 2914 participants with normal cognition, 697 with SCI, and 3972 with MCI aged 18 to 100 years from 55 studies. MAIN OUTCOMES AND MEASURES Prevalence of amyloid pathology on positron emission tomography or in cerebrospinal fluid according to AD risk factors (age, apolipoprotein E [APOE] genotype, sex, and education) estimated by generalized estimating equations. RESULTS The prevalence of amyloid pathology increased from age 50 to 90 years from 10% (95% CI, 8%-13%) to 44%(95% CI, 37%-51%) among participants with normal cognition; from 12%(95% CI, 8%-18%) to 43%(95% CI, 32%-55%) among patients with SCI; and from 27%(95% CI, 23%-32%) to 71%(95% CI, 66%-76%) among patients with MCI. APOE-epsilon 4 carriers had 2 to 3 times higher prevalence estimates than noncarriers. The age at which 15% of the participants with normal cognition were amyloid positive was approximately 40 years for APOE epsilon 4 epsilon 4 carriers, 50 years for epsilon 2 epsilon 4 carriers, 55 years for epsilon 3 epsilon 4 carriers, 65 years for epsilon 3 epsilon 3 carriers, and 95 years for epsilon 2 epsilon 3 carriers. Amyloid positivity was more common in highly educated participants but not associated with sex or biomarker modality. CONCLUSIONS AND RELEVANCE Among persons without dementia, the prevalence of cerebral amyloid pathology as determined by positron emission tomography or cerebrospinal fluid findings was associated with age, APOE genotype, and presence of cognitive impairment. These findings suggest a 20-to 30-year interval between first development of amyloid positivity and onset of dementia.
Original languageEnglish
Pages (from-to)1924-1938
JournalJAMA-Journal of the American Medical Association
Issue number19
Publication statusPublished - 19 May 2015


Dive into the research topics of 'Prevalence of Cerebral Amyloid Pathology in Persons Without Dementia A Meta-analysis'. Together they form a unique fingerprint.

Cite this