Representation of Alzheimer Disease and Related Dementias in a Statewide Population Genomics Cohort: Early Findings from In Our DNA SC.

Alzheimer Disease and Related Dementias (ADRD) affect more than 125,000 individuals in South Carolina, yet equitable representation in population genomics initiatives remains a concern. We conducted a cross-sectional descriptive analysis of 247 In Our DNA SC participants aged 50 to 89 years with at least 1 ADRD-related diagnosis, identified using ICD-10 codes, to characterize demographic and clinical features and to compare the cohort with statewide ADRD estimates. Most participants were aged 65 years or older (82.2%), female (52.2%), and White (93.1%), while only 5.3% identified as Black. Nearly half had a Charlson Comorbidity Index score of 4 or greater (48.6%), and 49.5% had at least 10 years of longitudinal electronic health record data. Compared with statewide ADRD estimates, Black individuals were substantially underrepresented despite comprising ∼one-third of ADRD cases in South Carolina. These findings highlight the need for continued efforts to improve representation and support equitable, generalizable precision health research.