Forecasting the 20-Year Incidence of Dementia by Socioeconomic Status, Race/Ethnicity, and Region Based on Mid-Life Risk Factors in a U.S. Nationally Representative Sample

Article type: Research Article

Authors: Churchill, Nicola^a | Barnes, Deborah E.^{b; c} | Habib, Mina^a | Nianogo, Roch A.^{a; d; *}

Affiliations: [a] Department of Epidemiology, Fielding School of Public Health, University of California Los Angeles (UCLA), Los Angeles, CA, USA | [b] Department of Psychiatry and Behavioral SciencesUniversity of California San Francisco (UCSF), San Francisco, CA, USA | [c] Department of Epidemiology and Biostatistics, University of California San Francisco (UCSF), San Francisco, CA, USA | [d] California Center for Population Research, University of California Los Angeles (UCLA), Los Angeles, CA, USA

Correspondence: [*] Correspondence to: Roch A. Nianogo, MD, PhD, Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA. Tel.: +1 310 267 5834; E-mail: [email protected].

Abstract: Background:Alzheimer’s disease and related dementias (ADRD) incidence varies based on demographics, but mid-life risk factor contribution to this variability requires more research. Objective:The purpose of this study is to forecast the 20-year incidence of dementia in the U.S. overall and stratified by race/ethnicity, socioeconomic status (SES), and U.S. geographic region given prior mid-life risk factor prevalence and to examine the extent to which risk factor differences 20 years ago may explain current SES, race/ethnicity, or regional disparities in dementia incidence. Methods:We applied the Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) prediction model to the 2006 wave of the Health and Retirement Study (HRS) in participants aged 45 to 64 to estimate the 20-year risk of incident ADRD. Results:The 20-year risk of dementia among middle-aged Americans was 3.3% (95% CI: 3.2%, 3.4%). Dementia incidence was forecast to be 1.51 (95% CI: 1.32, 1.71) and 1.27 (95% CI: 1.14, 1.44) times that in Hispanic and Non-Hispanic Black individuals respectively compared statistically to Non-Hispanic White individuals given mid-life risk factors. There was a progressive increase in dementia risk from the lowest versus highest SES quintile. For geographic region, dementia incidence was forecast to be 1.17 (95% CI: 1.06, 1.30) and 1.27 (95% CI: 1.14, 1.43) times that in Midwestern and Southern individuals respectively compared statistically to Western individuals. Conclusions:Some disparities in dementia incidence could be explained by differences in mid-life risk factors and may point toward policy interventions designed to lessen the ADRD disease burden through early prevention.

Keywords: Alzheimer’s disease, dementia, epidemiology, populations at risk, public health, risk reduction, statistical models

DOI: 10.3233/JAD-231133

Journal: Journal of Alzheimer's Disease, vol. 99, no. 4, pp. 1225-1234, 2024