Featured Article Individual estimates of age at detectable amyloid onset for risk factor assessment

Introduction: Individualized estimates of age at detectable amyloid-beta (Ab) accumulation, distinct from amyloid positivity, allow for analysis of onset age of Ab accumulation as an outcome measure to understand risk factors. Methods: UsinglongitudinalPittsburghcompoundB(PiB)positronemissiontomographydatafrom Baltimore Longitudinal Study of Aging, we estimated the age at which each PiB1 individual began accumulating Ab. We used survival analysis methods to quantify risk of accumulating Ab and differences in onset age of Ab accumulation in relation to APOE e4 status and sex among 36 APOE e4 carriers and 83 noncarriers. Results: Age at onset of Ab accumulation for the APOE e42 and e41 groups was 73.1 and 60.7, respectively. APOE e4 positivity conferred a threefold risk of accumulating Ab after adjusting for sex and education. Discussion: Estimation of onset age of amyloid accumulation may help gauge treatment efficacy in interventions to delay symptom onset in Alzheimer’s disease. Published by Elsevier Inc. on behalf of the Alzheimer’s Association.