For dementia ascertainment, the CCDSS applies a validated case-finding algorithm that identifies individuals as having dementia if they meet any of the following criteria: (i) one or more hospital separation records with a dementia/Alzheimer's disease diagnosis, (ii) three or more physician claims for dementia separated by at least 30 days within a two-year interval, or (iii) one or more prescriptions for cholinesterase inhibitor medications used to treat Alzheimer's disease. Here, BCHE is linked to early-onset autosomal dominant Alzheimer disease.