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Supplemental material, sj-pdf-1-jcb-10.1177_0271678X20957604 for Brain amyloid and vascular risk are related to distinct white matter hyperintensity patterns by Lene Pålhaugen, Carole H Sudre, Sandra Tecelao, Arne Nakling, Ina S Almdahl, Lisa F Kalheim, M Jorge Cardoso, Stein H Johnsen, Arvid Rongve, Dag Aarsland, Atle Bjørnerud, Per Selnes and Tormod Fladby in Journal of Cerebral Blood Flow & Metabolism

Supplemental material, sj-pdf-1-jcb-10.1177_0271678X20957604 for Brain amyloid and vascular risk are related to distinct white matter hyperintensity patterns by Lene Pålhaugen, Carole H Sudre, Sandra Tecelao, Arne Nakling, Ina S Almdahl, Lisa F Kalheim, M Jorge Cardoso, Stein H Johnsen, Arvid Rongve, Dag Aarsland, Atle Bjørnerud, Per Selnes and Tormod Fladby in Journal of Cerebral Blood Flow & Metabolism

ImportanceCerebral amyloid-β 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.ObjectiveTo 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 sourcesRelevant 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 selectionStudies 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 synthesisIndividual 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 measuresPrevalence 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.ResultsThe 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-ε4 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 ε4ε4 carriers, 50 years for ε2ε4 carriers, 55 years for ε3ε4 carriers, 65 years for ε3ε3 carriers, and 95 years for ε2ε3 carriers. Amyloid positivity was more common in highly educated participants but not associated with sex or biomarker modality.Conclusions and relevanceAmong 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.