Prevalence of Dementia and Mild Cognitive Impairment in the United States: Findings from the Health and Retirement Study (HRS) Harmonized Cognitive Assessment Protocol (HCAP) Project

Nationally representative data are critical for understanding the causes, costs and consequences of dementia and MCI in the US and can better inform policies aimed at reducing their impact on patients, families, and public programs. Because research on dementia is often based on highly selected samples of older adults who are disproportionately White, college‐educated, and high‐income, the nationally representative Health and Retirement Study (HRS) has become an essential resource for US population‐level information on dementia prevalence and incidence. However, the original HRS substudy providing dementia diagnostic information was fielded more than 20 years ago. We developed the Harmonized Cognitive Assessment Protocol (HCAP) to provide national estimates of the prevalence of MCI and dementia in the US and to examine differences by age, race and ethnicity, and gender.