A disproportionate burden of dementia has been reported among older adults who are Black, of mild cognitive impairment (MCI) among older adults who are Hispanic, and of both MCI and dementia among individuals of lower educational attainment, according to results from a cross-sectional study published in JAMA Neurology.
The Health and Retirement Study (HRS) is an ongoing longitudinal, nationally representative analysis of individuals aged 51 years or older with staggered entry dates from 1992 to 2022 and follow-up that ranged from 4 years to 30 years.
The Harmonized Cognitive Assessment Protocol (HCAP) project is a cross-sectional, random sample of persons in HRS who were aged 65 years and older in 2016. The aim of the HCAP project was to update national estimates on the prevalence of MCI and dementia in the United States, as well as to evaluate differences according to age, sex, race, and ethnicity.
Among 9972 age-eligible HRS participants, 4425 were randomly chosen for HCAP, with 3496 completing a comprehensive neuropsychological test battery and informant interview between June 2016 and October 2017, thus generating a final response rate of 79%. MCI and dementia were classified via use of an algorithm that was based on standard diagnostic criteria and compared test performance with a robust normative sample.
The mean age of the study population sample was 76.4±7.6 years. Overall, 60% of the participants were women.
Participants self-identified as the following:
- Black, not Hispanic (16%)
- Hispanic regardless of race (16%)
- White, not Hispanic (71%)
- Another race, including American Indian or Alaska Native, Asian, Native Hawaiian or Pacific Islander, or another self-described race (2%)
In all, 393 individuals (weighted percentage, 10%; 95% CI, 9-11) were classified as having dementia (mean age, 82.3±7.4 years; 62% women) and 804 individuals (weighted percentage, 22%; 95% CI, 20-24) were classified as having MCI (mean age, 76.8±7.8 years; 59% women).
Individuals with dementia were:
- Older (weighted odds ratio [OR], 1.95 per 5-year age difference; 95% CI, 1.77-2.14)
- Attended fewer years of school (weighted and age-adjusted OR, 0.93 per year of school; 95% CI, 0.89-0.97)
- More likely to be Black than White (weighted and age-adjusted OR, 1.81 for Black; 95% CI, 1.20-2.75)
Individuals who were older (weighted OR, 1.17 per 5-year age difference; 95% CI, 1.09-1.26), had fewer years of school (weighted and age-adjusted OR, 0.94 per year of school; 95% CI, 0.91-0.97), and were Hispanic (weighted and age-adjusted OR, 1.42; 95% CI, 1.03-1.96) were more likely to have MCI.
Other group comparisons based on race and ethnicity were not possible because of the small numbers of individuals. No differences in prevalence were reported between women and men participants.
Limitations of the current analysis warrant mention. Although the in-person HCAP evaluation was comprehensive, it was not as thorough as that typically obtained for gold-standard diagnoses in clinical settings. As a result, information on dementia subtypes was not available in HCAP. Since this was a cross-sectional study of the prevalence of dementia and MCI, the incidence of cognitive impairment or rates of progression among individuals with MCI could not be assessed.
“In conclusion, the HCAP study found a similar prevalence of dementia and MCI among older adults in the US to that found in other recent studies in the US,” the researchers stated.
They also acknowledged that “The results suggest there may be disparities in dementia and MCI among Black and Hispanic older adults and people with lower educational attainment.”
Disclosure: Some of the study authors have declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
This article originally appeared on Neurology Advisor
Manly JJ, Jones RN, Langa KM, et al. Estimating the prevalence of dementia and mild cognitive impairment in the US: the 2016 Health and Retirement Study Harmonized Cognitive Assessment Protocol project. JAMA Neurol. Published online October 24, 2022. doi:10.1001/jamaneurol.2022.3543