Stability and Change in Cognitive Status Classification of Black Older Adults

Pulmonary function and trajectories of cognitive decline in aging population

BACKGROUND

The number of older people with cognitive impairment is increasing worldwide. Impaired lung function might be associated with cognitive decline in older age; however, results from large longitudinal studies are lacking. In this study, we examined the longitudinal associations between pulmonary function and the trajectories of cognitive decline using prospective population-based SHARE data from 14 countries.

METHODS

The analytic sample included N = 32,049 older adults (Mean age at baseline = 64.76 years). The dependent variable was cognitive performance, measured repeatedly across six waves in three domains: verbal fluency, memory, and numeracy. The main predictor of interest was peak expiratory flow (PEF). The data were analyzed in a multilevel accelerated longitudinal design, with models adjusted for a variety of covariates.

RESULTS

A lower PEF score was associated with lower cognitive performance for each domain as well as a lower global cognitive score. These associations remained statistically significant after adjusting for all covariates Q4 vs Q1 verbal fluency: unstandardized coefficient B = -3.15; numeracy: B = -0.52; memory: B = -0.64; global cognitive score B = -2.65, all p < .001). However, the PEF score was not found to be associated with the rate of decline for either of the cognitive outcomes.

CONCLUSIONS

In this large multi-national longitudinal study, the PEF score was independently associated with lower levels of cognitive functions, but it did not predict a future decline. The results suggest that pre-existing differences in lung functions are responsible for variability in cognitive functions and that these differences remained stable across aging.

Stability in cognitive classification as a function of severity of impairment and ethnicity: A longitudinal analysis

OBJECTIVE

The interaction of ethnicity, progression of cognitive impairment, and neuroimaging biomarkers of Alzheimer's Disease remains unclear. We investigated the stability in cognitive status classification (cognitively normal [CN] and mild cognitive impairment [MCI]) of 209 participants (124 Hispanics/Latinos and 85 European Americans).

METHODS

Biomarkers (structural MRI and amyloid PET scans) were compared between Hispanic/Latino and European American individuals who presented a change in cognitive diagnosis during the second or third follow-up and those who remained stable over time.

RESULTS

There were no significant differences in biomarkers between ethnic groups in any of the diagnostic categories. The frequency of CN and MCI participants who were progressors (progressed to a more severe cognitive diagnosis at follow-up) and non-progressors (either stable through follow-ups or unstable [progressed but later reverted to a diagnosis of CN]) did not significantly differ across ethnic groups. Progressors had greater atrophy in the hippocampus (HP) and entorhinal cortex (ERC) at baseline compared to unstable non-progressors (reverters) for both ethnic groups, and more significant ERC atrophy was observed among progressors of the Hispanic/Latino group. For European Americans diagnosed with MCI, there were 60% more progressors than reverters (reverted from MCI to CN), while among Hispanics/Latinos with MCI, there were 7% more reverters than progressors. Binomial logistic regressions predicting progression, including brain biomarkers, MMSE, and ethnicity, demonstrated that only MMSE was a predictor for CN participants at baseline. However, for MCI participants at baseline, HP atrophy, ERC atrophy, and MMSE predicted progression.

Discrimination and Education Quality Moderate the Association of Sleep With Cognitive Function in Older Black Adults: Results From the Einstein Aging Study

OBJECTIVES

Heterogeneity among Black adults' experiences of discrimination and education quality independently influence cognitive function and sleep, and may also influence the extent to which sleep is related to cognitive function. We investigated the effect of discrimination on the relationship between objective sleep characteristics and cognitive function in older Black adults with varying education quality.

METHOD

Cross-sectional analyses include Black participants in the Einstein Aging Study (N = 104, mean age = 77.2 years, 21% males). Sleep measures were calculated from wrist actigraphy (15.4 ± 1.3 days). Mean ambulatory cognitive function (i.e., spatial working memory, processing speed/visual attention, and short-term memory binding) was assessed with validated smartphone-based cognitive tests (6 daily). A modified Williams Everyday Discrimination Scale measured discriminatory experiences. Linear regression, stratified by reading literacy (an indicator of education quality), was conducted to investigate whether discrimination moderated associations between sleep and ambulatory cognitive function for individuals with varying reading literacy levels. Models controlled for age, income, sleep-disordered breathing, and sex assigned at birth.

RESULTS

Higher reading literacy was associated with better cognitive performance. For participants with both lower reading literacy and more discriminatory experiences, longer mean sleep time was associated with slower processing speed, and lower sleep quality was associated with worse working memory. Later sleep midpoint and longer nighttime sleep were associated with worse spatial working memory for participants with low reading literacy, independent of their discriminatory experiences.

DISCUSSION

Sociocultural factors (i.e., discrimination and education quality) can further explain the association between sleep and cognitive functioning and cognitive impairment risk among older Black adults.

Association of impaired lung function with dementia, and brain magnetic resonance imaging indices: a large population-based longitudinal study

OBJECTIVE

to examine the association between different patterns of impaired lung function with the incident risk of dementia and magnetic resonance imaging (MRI)-based brain structural features.

METHODS

in UK Biobank, a total of 308,534 dementia-free participants with valid lung function measures (forced expiratory volume in 1 s [FEV1] and forced vital capacity [FVC]) were included. Association was assessed using Cox proportional hazards regression model. Furthermore, the association between impaired lung function and brain MRI biomarkers related to cognitive function was analysed among 30,159 participants.

RESULTS

during a median follow-up of 12.6 years, 3,607 incident all-cause dementia cases were recorded. Restrictive impairment (hazard ratio [HR], 1.42; 95% confidence interval [CI], 1.27-1.60) and obstructive impairment (HR, 1.28; 95% CI, 1.15-1.42) were associated with higher risk of all-cause dementia. The restricted cubic splines indicated FEV1% predicted and FVC % predicted had reversed J-shaped associations with dementia. Participants with impaired lung function have higher risks of all-cause dementia across all apolipoprotein E (APOE) risk categories, whereas associations were stronger among those of low APOE risk (P for interaction = 0.034). In addition, restrictive and obstructive impairment were linked to lower total (β: -0.075, SE: 0.021, Pfdr = 0.002; β: -0.033, SE: 0.017, Pfdr = 0.069) and frontoparietal grey matter volumes, higher white matter hyperintensity, poorer white matter integrity, lower hippocampus (β: -0.066, SE: 0.024, Pfdr = 0.017; β: -0.051, SE: 0.019, Pfdr = 0.019) and other subcortical volumes.

CONCLUSIONS

participants with restrictive and obstructive impairments had a higher risk of dementia. Brain MRI indices further supported adverse effects and provided insight into potential pathophysiology biomarkers.

Pulmonary Function in Midlife as a Predictor of Later-Life Cognition: The Coronary Artery Risk Development in Adults (CARDIA) Study

BACKGROUND

Studies found associations between pulmonary function (PF) and cognition, but these are limited by mostly cross-sectional design and a single measure of PF (typically forced expiratory volume in 1 second [FEV1]). Our objective was to prospectively analyze the association of repeatedly measured PF with cognition.

METHODS

We studied 3 499 participants in the Coronary Artery Risk Development in Young Adults cohort with cognition measured at year 25 (Y25) and Y30, and PF (FEV1 and forced vital capacity [FVC], reflecting better PF) measured up to 6 times from Y0 to Y20. Cognition was measured via Stroop test, Rey-Auditory Verbal Learning Test [RAVLT], and digit symbol substitution test [DSST], which capture executive function, verbal learning and memory, and attention and psychomotor speed, respectively; lower Stroop, and higher RAVLT and DSST scores indicate better cognition. We modeled linear, cross-sectional associations between cognition and PF at Y30 (mean age 55), and mixed models to examine associations between cognition at Y25-Y30 and longitudinal PF (both annual rate of change, and cumulative PF from Y0 to Y20).

RESULTS

At Y30, FEV1 and FVC were cross-sectionally associated with all 3 measures of cognition (β = 0.08-0.12, p < .01-.02). Annual change from peak FEV1/FVC ratio was associated with Stroop and DSST (β = 18.06, 95% CI = 7.71-28.40; β = 10.30, 95% CI = 0.26-20.34, respectively), but not RAVLT. Cumulative FEV1 and FVC were associated with Stroop and DSST (β = 0.07-0.12, p < .01-.02), but only cumulative FEV1 was associated with RAVLT (β = 0.07, 95% CI = 0.00-0.14).

CONCLUSIONS

We identified prospective associations between measures of PF and cognition even at middle ages, adding evidence of a prospective association between reduced PF and cognitive decline.

A lifecourse approach to the relationship between lung function and cognition function in late life: findings from the Mysore studies of Natal effect on Ageing and Health (MYNAH) in South India

Background: Emerging evidence from high income settings indicates that lung function may be an independent determinant of cognitive abilities in late life. Despite a high burden of chronic lung disorders and neurocognitive disorders, there are limited data exploring the relationship between lung and cognitive function in later life in low- and middle-income (LMIC) settings. Methods: Between 2013 and 2016, 721 men and women from the Mysore Birth Records Cohort in South India, aged 55-80 years, were retraced and underwent standardised assessments for sociodemographic characteristics, cardiometabolic risk factors, lung function, cognitive function and mental health. Approximately 20 years earlier, a subset of them had assessments for cardiometabolic risk factors (n=522) and lung function (n=143). Results: Forced Expiratory Volume at one second (FEV1) and six seconds (FEV6) were higher among men than women. Women had higher immediate and delayed recall scores compared to men. Multivariate models indicated that those with lower FEV1 (lts) and FEV1/FEV6 ratio in late life had lower composite cognitive score (SD, standard deviation), independent of growth and environment in early life and childhood, attained education, socioeconomic position, cardiometabolic disorders in mid-and late life and lifestyle factors (0.29 SD per litre 95% confidence interval [CI] (0.10, 0.50) p=0.006 for FEV1 and 1.32 SD (0.20, 2.50) p=0.02 for FEV1/FEV6 ratio). Lung function in midlife was unrelated to cognitive outcomes in late life. Conclusions: Causality cannot be inferred from cross sectional associations. Therefore, causality is best explored in longitudinal studies with serial, but contemporaneous measurements of both lung and cognitive function. Mechanistic studies that examine the role of shared risk factors like environmental pollutants and biomass exposure on this relationship are urgently required in LMICs.

The Effects of Selective Survival on Black Adults' Cognitive Development

OBJECTIVES

The theory of selective survival suggests that possibly around 70-75 years of age, Blacks may display substantive changes in their pattern of cognitive decline. This study examined the age-graded pattern of cognitive decline within older Blacks by describing a trend that characterizes differences in the change of cognitive decline from ages 51.5 to 95.5, and hypothesized that this age-graded pattern is nonlinear.

METHOD

Utilizing 2 waves of longitudinal data from the Baltimore Study of Black Aging, this study used multilevel modeling to test whether the interaction between age and the 3-year study period (time between waves) had a positive effect on changes in inductive reasoning, declarative memory, working memory, and perceptual speed.

RESULTS

A significant positive interaction between age and wave was found for inductive reasoning, demonstrating an age-grade pattern of change/decline in cognitive pattern for Blacks aged 51.5-95.4. Simple slope probing via the Johnson-Neyman Technique suggested that Black adults ~64 years and younger experienced significant decline in inductive reasoning across study time, whereas for those older than 63.71, the decline was nonsignificant. No significant age-wave interactions were found for declarative memory, working memory, or perceptual speed.

DISCUSSION

Findings suggest a selective survival effect for inductive reasoning ability among Blacks. With decline evident so early, common cognitive intervention programs targeting adults 65+ may come too late for Blacks, signifying the importance and urgency for early health interventions and public policy designed to promote cognitive reserve.

Systematic Review of Pulmonary Function and Cognition in Aging

BACKGROUND

Substantial research is dedicated to understanding the aging-related dynamics among individual differences in level, change, and variation across physical and cognitive abilities. Evaluating replicability and synthesizing findings has been limited by differences in measurements, samples, study design, and statistical analyses that confound between-person differences with within-person changes. Here, we systematically reviewed longitudinal results on the aging-related dynamics linking pulmonary function and cognitive performance.

METHODS

Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines were used to systematically review longitudinal studies of pulmonary function and cognition.

RESULTS

Only four studies thoroughly investigating cognitive and pulmonary longitudinal associations (three or more measurement occasions) were identified. Expanded review criteria identified three studies reporting two measurement occasions, and seven studies reporting one measurement of pulmonary function or cognition and two or more measurements of the other. We identified numerous methodological quality and risk for bias issues across studies.

CONCLUSIONS

Despite documented correlational associations between pulmonary function and cognition, these results show there is very limited research thoroughly investigating their longitudinal associations. This highlights the need for longitudinal data, rigorous methodological design including key covariates, and clear communication of methods and analyses to facilitate replication across an array of samples. We recommend systematic study of outcome measures and covariates, inclusion of multiple measures (e.g., peak expiratory flow, forced expiratory volume in 1 s, and forced vital capacity), as well as application of the same analytic approach across multiple datasets.

Factors for predicting reversion from mild cognitive impairment to normal cognition: A meta-analysis

OBJECTIVE

Subjects with mild cognitive impairment (MCI) may revert to normal cognition (NC), but predictive factors are under study. We therefore sought to identify factors which could help in predicting reversion from MCI to NC.

METHODS

Relevant studies were retrieved from PubMed, EMBASE, Cochrane Library, MEDLINE, Web of Science, EBSCO, and OVID. According to the inclusion and exclusion criteria, high-quality assessments of relevant literatures were conducted, followed by data extraction and meta-analysis with Stata 12.0 software.

RESULTS

A total of 17 studies with 6829 participants were included in the meta-analysis. The overall reversion rate is 27.57%. Positive predictive factors were found in younger age (SMD = -0.345, 95% CI, -0.501 to -0.189), higher education level (SMD = 0.337, 95% CI, 0.117-0.558), no APOE ε4 allele (OR = 0.728, 95% CI, 0.575-0.922), no hypertension (OR = 0.826, 95% CI, 0.692-0.987), no stroke (OR = 0.696, 95% CI, 0.507-0.953), and higher Mini-Mental State Examination (MMSE) score (SMD = 0.707, 95% CI, 0.461-0.953).

CONCLUSION

Individuals who are at young age, have higher education level and MMSE score, and have no APOEe4 allele, no hypertension, and no stroke had a high probability to revert from MCI to NC.