BACKGROUND: Recent genome-wide association studies (GWAS) for Alzheimer's Disease and related dementias (ADRD) have increased statistical power via larger analysis datasets from biobanks by 1) including non-age-matched controls and prevalent cases, and/or 2) including individuals who report a family history of ADRD as proxy cases. However, these methods have the potential to increase noise and distort genetic associations which are important for genomic-informed prevention and treatment of ADRD....