Secular Trends in the Incidence of Dementia in a Multi-Ethnic Community

Article type: Research Article

Authors: Noble, James M.^{a; b; c; 1; *} | Schupf, Nicole^{a; b; c; d; 1} | Manly, Jennifer J.^{a; b; c} | Andrews, Howard^e | Tang, Ming-Xin^b | Mayeux, Richard^{a; b; c}

Affiliations: [a] Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University, New York, NY, USA | [b] G.H. Sergievsky Center, Columbia University, New York, NY, USA | [c] Department of Neurology, Columbia University Medical Center, New York, NY, USA | [d] Department of Epidemiology, Columbia University Medical Center, New York, NY, USA | [e] Department of Biostatistics, Mailman School of Public Health, Columbia University Medical Center, New York, NY, USA

Correspondence: [*] Correspondence to: James M. Noble, MD, MS, CPH, Assistant Professor of Neurology at CUMC, Department of Neurology, Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, and G.H. Sergievsky Center, Columbia University, 710 W. 168th St., New York, NY 10032, USA. Tel.: +1 212 342 4126; Fax: +1 212 305 1145; E-mail: jn2054@columbia.edu.

Note: [1] These authors contributed equally to this work.

Abstract: Background:Determination of secular trends in cognitive aging is important for prioritization of resources, services, and research in aging populations. Prior studies have identified declining dementia incidence associated with changes in cardiovascular risk factors and increased educational attainment. However, few studies have examined these factors in multi-ethnic cohorts. Objective:To identify secular trends in the incidence rate of dementia in an elderly population. Methods:Participants in this study were drawn from the Washington Heights-Inwood Columbia Aging Project, a multi-ethnic cohort study of northern Manhattan residents aged 65 years and older. Cox proportional hazards models were used to examine differences in the incidence of dementia in cohorts recruited in 1992 and 1999, with age at dementia or age at last follow-up visit as the “time-to-event” variable. Results:Overall, there was a 41% reduction in the hazard ratio for dementia among participants in the 1999 cohort compared with those in the 1992 cohort, adjusting for age, sex, race, and baseline memory complaints (HR = 0.59). The reduction in incidence was greatest among non-Hispanic Whites and African-Americans and lowest among Hispanic participants (HRs = 0.60, 0.52 and 0.64, respectively), and was associated with increases in level of educational attainment, especially among African-Americans. Reduction in incidence of dementia was also greater among persons 75 years or older than among younger participants (HR = 0.52 versus HR = 0.69). Conclusions:Our results support previous findings that secular trends in dementia incidence are changing, including in aging minority populations.

Keywords: Cohorts, dementia, incidence, race/ethnicity, secular trends

DOI: 10.3233/JAD-170300

Journal: Journal of Alzheimer's Disease, vol. 60, no. 3, pp. 1065-1075, 2017