• Analysis of the impact of risk factors and recruitment settings on prescreening • Participation in the EPAD LCS was associated with lower age, higher education, male sex and family history of dementia • Amyloid positivity was associated with higher age and APOE ε4 allele carrier status • Results were similar across all prescreen settings (clinical cohort, research in-person cohort, research online cohort, population based cohort). This evidence concerns the gene APOE and dementia.