Objective: In light of growing debate over whether and how early life educational experiences alter late-life cognitive trajectories, this study sought to more thoroughly investigate the relationship ...between educational attainment and rates of late-life cognitive decline in a racially, ethnically, and educationally diverse population. Method: Older adults (N = 3,435) in the community-based Washington Heights-Inwood Columbia Aging Project were administered neuropsychological tests of memory, language, visuospatial function, and processing speed at approximate 24-month intervals for up to 18 years. Second-order latent growth curves estimated direct and indirect (through income) effects of educational attainment on rates of global cognitive decline separately in individuals with low (0-8 years) and high (9-20 years) educational attainment. Results: More years of education were associated with higher cognitive level and slower cognitive decline in individuals with low or high educational attainment. The association between having more than 9 years of education and exhibiting slower cognitive decline was fully mediated by income. Although having additional years of education up to 8 years was also associated with higher income, this did not explain associations between education and cognitive change in the low-education group. Conclusions: Early education (i.e., up to 8 years) may promote aspects of development during a sensitive period of childhood that protect against late-life cognitive decline independent of income. In contrast, later education (i.e., 9 years and beyond) is associated with higher income, which may influence late-life cognitive health through multiple, nonmutually exclusive pathways.
Availability of safe and effective treatments for Alzheimer disease is an urgent challenge given the global shift toward an older population and increased risk of mild cognitive impairment and ...dementia as people age.1,2 Dementia-related burdens are disproportionately felt within historically marginalized communities because structural inequalities rooted in racism, xenophobia, and sexism increase risk factors for cognitive impairment, increase barriers to diagnosis, and reduce access to care.
IMPORTANCE: Nationally representative data are critical for understanding the causes, costs, and outcomes associated with dementia and mild cognitive impairment (MCI) in the US and can inform ...policies aimed at reducing the impact of these conditions on patients, families, and public programs. The nationally representative Health and Retirement Study (HRS) is an essential resource for such data, but the HRS substudy providing dementia diagnostic information was fielded more than 20 years ago and more recent data are needed. OBJECTIVE: The Harmonized Cognitive Assessment Protocol (HCAP) was developed to update national estimates of the prevalence of MCI and dementia in the US and examine differences by age, race, ethnicity, and sex. DESIGN, SETTING, AND PARTICIPANTS: HRS is an ongoing longitudinal nationally representative study of people 51 years and older with staggered entry dates from 1992 to 2022 and follow-up ranging from 4 to 30 years. HCAP is a cross-sectional random sample of individuals in HRS who were 65 years or older in 2016. Of 9972 age-eligible HRS participants, 4425 were randomly selected for HCAP, and 3496 completed a comprehensive neuropsychological test battery and informant interview, none of whom were excluded. Dementia and MCI were classified using an algorithm based on standard diagnostic criteria and comparing test performance to a robust normative sample. EXPOSURES: Groups were stratified by age, sex, education, race, and ethnicity. MAIN OUTCOMES AND MEASURES: National prevalence estimates using population weights. RESULTS: The mean (SD) age of the study population sample (N = 3496) was 76.4 (7.6) years, and 2095 participants (60%) were female. There were 551 participants who self-identified as Black and not Hispanic (16%), 382 who self-identified as Hispanic regardless of race (16%), 2483 who self-identified as White and not Hispanic (71%), and 80 who self-identified as another race (2%), including American Indian or Alaska Native, Asian, Native Hawaiian or Pacific Islander, or another self-described race. A total of 393 individuals (10%; 95% CI, 9-11) were classified as having dementia and 804 (22%; 95% CI, 20-24) as having MCI. Every 5-year increase in age was associated with higher risk of dementia (weighted odds ratio OR, 1.95 per 5-year age difference; 95%, CI, 1.77-2.14) and MCI (OR, 1.17 per 5-year age difference, 95% CI, 1.09-1.26). Each additional year of education was associated with a decrease in risk of dementia (OR, 0.93 per year of school, 95% CI, 0.89-0.97) and MCI (OR, 0.94, 95% CI, 0.91-0.97). Dementia was more common among non-Hispanic Black individuals (OR, 1.81; 95% CI, 1.20-2.75) and MCI in Hispanic individuals (OR, 1.42; 95% CI, 1.03-1.96) compared with non-Hispanic White individuals. Other group comparisons by race and ethnicity were not possible owing to small numbers. No differences in prevalence were found between female individuals and male individuals. CONCLUSIONS AND RELEVANCE: Using a comprehensive neuropsychological test battery and large sample, the national prevalence of dementia and MCI in 2016 found in this cross-sectional study was similar to that of other US-based studies, indicating a disproportionate burden of dementia and MCI among older Black and Hispanic adults and those with lower education.
AbstractObjectiveTo evaluate trials of drugs that target amyloid to determine whether reductions in amyloid levels are likely to improve cognition.DesignInstrumental variable meta-analysis.Setting14 ...randomized controlled trials of drugs for the prevention or treatment of Alzheimer’s disease that targeted an amyloid mechanism, identified from ClinicalTrials.gov.PopulationAdults enrolled in randomized controlled trials of amyloid targeting drugs. Inclusion criteria for trials vary, but typically include adults aged 50 years or older with a diagnosis of mild cognitive impairment or Alzheimer’s disease, and amyloid positivity at baseline.Main outcome measuresAnalyses included trials for which information could be obtained on both change in brain amyloid levels measured with amyloid positron emission tomography and change in at least one cognitive test score reported for each randomization arm.ResultsPooled results from the 14 randomized controlled trials were more precise than estimates from any single trial. The pooled estimate for the effect of reducing amyloid levels by 0.1 standardized uptake value ratio units was an improvement in the mini-mental state examination score of 0.03 (95% confidence interval −0.06 to 0.1) points. This study provides a web application that allows for the re-estimation of the results when new data become available and illustrates the magnitude of the new evidence that would be necessary to achieve a pooled estimate supporting the benefit of reducing amyloid levels.ConclusionsPooled evidence from available trials reporting both reduction in amyloid levels and change in cognition suggests that amyloid reduction strategies do not substantially improve cognition.
•Ambient air pollution is associated with more rapid cognitive decline in older adults.•APOE-ε4 positive individuals had more rapid pollution-associated cognitive decline.•The association was also ...stronger among Non-Hispanic individuals.•No difference in strength of association between age groups, sex, or smoking status.
There is mounting evidence that long-term exposure to air pollution is related to accelerated cognitive decline in aging populations. Factors that influence individual susceptibility remain largely unknown, but may involve the apolipoprotein E genotype E4 (APOE-ε4) allele.
We assessed whether the association between long-term exposure to ambient air pollution and cognitive decline differed by APOE-ε4 status and cognitive risk factors.
The Washington Heights Inwood Community Aging Project (WHICAP) is a prospective study of aging and dementia. Neuropsychological testing and medical examinations occur every 18–24 months. We used mixed-effects models to evaluate whether the association between markers of ambient air pollution (nitrogen dioxide NO2), fine PM2.5, and coarse PM10 particulate matter) and the rate of decline in global and domain-specific cognition differed across strata defined by APOE-ε4 genotypes and cognitive risk factors, adjusting for sociodemographic factors and temporal trends.
Among 4821 participants with an average of 6 years follow-up, higher concentrations of ambient air pollution were associated with more rapid cognitive decline. This association was more pronounced among APOE-ε4 carriers (p < 0.001). A one interquartile range increase in NO2 was associated with an additional decline of 0.09 standard deviations (SD) (95%CI −0.1, −0.06) in global cognition across biennial visits among APOE-ε4 positive individuals and a 0.07 SD (95%CI −0.09, −0.05) decline among APOE-ε4 negative individuals. Results for PM2.5, PM10 and cognitive domains were similar. The association between air pollutants and rate of cognitive decline also varied across strata of race-ethnicity with the association strongest among White non-Hispanic participants.
These results add to the body of evidence on the adverse impact of ambient air pollution on cognitive aging and brain health and provide new insights into the genetic and behavioral factors that may impact individual susceptibility.
The associations between self-reported current and past leisure time physical activity (LTPA) and Alzheimer's disease (AD) incidence were determined using data from the multiethnic ...Washington/Hamilton Heights-Inwood Columbia Aging Project (WHICAP) study.
The metabolic equivalent of LTPA energy expenditure was calculated for self-reported current and past LTPA for 1345 older adults. A Cox proportional hazard model was conducted to estimate the association between LTPA (low, middle, and high) and incident AD risk.
Comparing high to low level, current and past LTPA were both associated with reduced AD risk, with hazard ratio (95% confidence interval) = 0.39 (0.20–0.75) and 0.37 (0.18–0.75), respectively. Compared with “always low,” “increased” and “always high” LTPA throughout life were associated with reduced AD risk, with hazard ratio (95% confidence interval) = 0.60 (0.36–0.99) and 0.28 (0.08–0.94), respectively. Light- and moderate-intensity LTPA were associated with lower AD risk.
LTPA both throughout life and later in life are associated with lower risk of AD.
•More current and earlier-life LTPA were associated with reduced risk of Alzheimer's disease (AD).•Increasing or maintaining high LTPA throughout life was protective against AD.•Avoiding being physically inactive throughout life was beneficial for prevention of AD.•There was a health benefit in AD prevention by performing light and moderate LTPAs.
Objectives: Social engagement has been linked to preserved cognitive functioning in later life. While social engagement is often operationalized as social network size, social networks can vary not ...only in size, but also in composition. Previous work has found that having a greater proportion of family in a network is associated with worse socioemotional and cognitive outcomes compared to having a greater proportion of friends. In addition, social resources may differentially affect cognition in minority groups at higher risk of cognitive impairment. Therefore, the current study aimed to examine racial/ethnic differences in the relationship between network characteristics and cognition. Method: Ethnically and racially diverse older adults from the Washington Heights-Inwood Columbia Aging Project (n = 548, 60-93 years) were used. Multiple regressions were conducted to examine the effects of ethnicity/race, size, composition, and their interaction on global cognition. Results: Analyses revealed that networks with a greater proportion of friends were associated with better global cognition than networks with a greater proportion of family. Additionally, larger social network size was only associated with better global cognition among individuals who had a greater proportion of friends in their networks. Race further moderated this effect, as it was limited to African Americans. Discussion: Overall, these findings highlight the importance of looking at both composition and size when examining the relationship between social network characteristics and global cognition. These findings suggest that friendships may be especially important and further suggest that social network characteristics and cognitive aging may be more strongly related among African Americans.
General Scientific Summary
The current study's findings suggest that social network characteristics may be a potentially relevant and modifiable social resource for reducing racial disparities in cognitive aging. These findings specifically emphasize that friendships may be particularly important for maintaining cognitive functioning for African American older adults.
Structural magnetic resonance imaging (MRI) provides key biomarkers to predict onset and track progression of Alzheimer's disease (AD). However, most published reports of relationships between MRI ...variables and cognition in older adults include racially, ethnically, and socioeconomically homogenous samples. Racial/ethnic differences in MRI variables and cognitive performance, as well as health, socioeconomic status and psychological factors, raise the possibility that brain-behavior relationships may be stronger or weaker in different groups. The current study tested whether MRI predictors of cognition differ in African Americans and Hispanics, compared with non-Hispanic Whites.
Participants were 638 non-demented older adults (29% non-Hispanic White, 36% African American, 35% Hispanic) in the Washington Heights-Inwood Columbia Aging Project. Composite scores of memory, language, speed/executive functioning, and visuospatial function were derived from a neuropsychological battery. Hippocampal volume, regional cortical thickness, infarcts, and white matter hyperintensity (WMH) volumes were quantified with FreeSurfer and in-house developed procedures. Multiple-group regression analysis, in which each cognitive composite score was regressed onto MRI variables, demographics, and cardiovascular health, tested which paths differed across groups.
Larger WMH volume was associated with worse language and speed/executive functioning among African Americans, but not among non-Hispanic Whites. Larger hippocampal volume was more strongly associated with better memory among non-Hispanic Whites compared with Hispanics. Cortical thickness and infarcts were similarly associated with cognition across groups.
The main finding of this study was that certain MRI predictors of cognition differed across racial/ethnic groups. These results highlight the critical need for more diverse samples in the study of cognitive aging, as the type and relation of neurobiological substrates of cognitive functioning may be different for different groups.
The Harmonized Cognitive Assessment Protocol (HCAP) Project is a substudy within the Health and Retirement Study (HRS), an ongoing nationally representative panel study of about 20,000 adults aged 51 ...or older in the United States. The HCAP is part of an international research collaboration funded by the National Institute on Aging to better measure and identify cognitive impairment and dementia in representative population-based samples of older adults, in the context of ongoing longitudinal studies of aging in high-, middle-, and low-income countries around the world.
The HCAP cognitive test battery was designed to measure a range of key cognitive domains affected by cognitive aging (including attention, memory, executive function, language, and visuospatial function) and to allow harmonization and comparisons to other studies in the United States and around the world. The HCAP included a pair of in-person interviews, one with the target HRS respondent (a randomly selected HRS sample member, aged 65+) that lasted approximately 1 h and one with an informant nominated by the respondent that lasted approximately 20 min. The final HRS HCAP sample included 3,496 study subjects, representing a 79% response rate among those invited to participate.
Linking detailed HCAP cognitive assessments to the wealth of available longitudinal HRS data on cognition, health, biomarkers, genetics, health care utilization, informal care, and economic resources and behavior will provide unique and expanded opportunities to study cognitive impairment and dementia in a nationally representative US population-based sample. The fielding of similar HCAP projects in multiple countries around the world will provide additional opportunities to study international differences in the prevalence, incidence, and outcomes of dementia globally with comparable data. Like all HRS data, HCAP data are publicly available at no cost to researchers.
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