Estimates of preclinical AD with subjective cognitive decline in nine major European countries

Of the ∼8 million individuals in nine European countries with preAD and SCD symptoms, only 5.5% would likely be identifiable and eligible for a trial of preAD individuals. Future work should incorporate tau pathology and APOE ε4 status into estimates. Accelerating development of biomarkers and other diagnostic tools is important to identifying additional preAD trial participants.