Subjective cognitive concerns, episodic memory, and the APOE ε4 allele

Body mass index changes and trajectories from midlife to late-life: association with subjective cognitive complaints in a 30-year Women's cohort study

BACKGROUND

The relationship between body mass index (BMI) changes across the lifespan and cognitive health in later life remains unclear. This study evaluated the association between BMI changes from midlife to late-life and subsequent subjective cognitive complaints (SCCs) in women.

METHODS

We analysed data from 5160 women in the New York University Women's Health Study, a prospective cohort with over 30 years of follow-up. BMI was calculated using self-reported height and weight at baseline and follow-up. SCCs were assessed using a validated questionnaire in 2018-2020. Odds ratios (ORs) for reporting ≥2 SCCs were estimated using unconditional logistic regression.

RESULTS

BMI at specific life stages was not significantly associated with SCC risk. BMI changes from midlife to late-life were associated with SCC risk. Compared to women with stable BMI (≤5% change), moderate BMI loss (5.1-10% decrease) was associated with higher odds of ≥2 SCCs (OR: 1.23, 95% CI: 1.02-1.48), large BMI gain (>10% increase) was associated with lower odds of ≥2 SCCs (OR: 0.81, 95% CI: 0.67-0.97). These findings were consistent across sensitivity analyses, including varying age cut-offs and excluding BMI changes occurring 5-10 years before late-life.

CONCLUSIONS

Our findings emphasize the importance of considering lifelong weight changes in assessing cognitive health risks. In particular, significant weight loss from midlife to late-life may serve as a potential indicator of cognitive decline in older adults. Further research is needed to elucidate the underlying mechanisms of this association and to explore effective interventions for mitigating cognitive health risks.

Dietary Carbohydrate Intake, Carbohydrate Quality, and Healthy Aging in Women

Importance

Dietary carbohydrate quality is inversely associated with risks of chronic disease and all-cause mortality. However, limited evidence exists regarding the role of carbohydrate quality and dietary carbohydrate types in promoting healthy aging.

Objective

To evaluate the long-term role of dietary carbohydrate intake and carbohydrate quality in healthy aging.

Design, Setting, and Participants

This prospective cohort study used data from the Nurses' Health Study (NHS) from January 1984 to December 2016 and included participants aged younger than 60 years in 1984. Data were analyzed from January 2023 to February 2025.

Exposure

Intakes of total carbohydrates; refined carbohydrates; high-quality carbohydrates from whole grains, fruits, vegetables, and legumes; dietary fiber; and the dietary glycemic index (GI) and glycemic load (GL).

Main Outcomes and Measures

Nutrient intakes were derived from 1984 and 1986 food frequency questionnaires. The primary outcome was healthy aging, defined as the absence of major chronic diseases, lack of cognitive and physical function impairments, and having good mental health, according to 2014 or 2016 NHS questionnaire data. Multivariate logistic regression was used to calculate associations of each carbohydrate variable with healthy aging.

Results

Among 47 513 participants (mean [SD] baseline age, 48.5 [6.2] years), 3706 (7.8%) met our healthy aging definition. Every 10%-calorie increment in intakes of total carbohydrates (odds ratio [OR], 1.17; 95% CI, 1.10-1.25) and high-quality carbohydrates (OR, 1.31; 95% CI, 1.22-1.41) was positively associated with healthy aging. Refined carbohydrates were associated with lower odds of healthy aging (OR, 0.87; 95% CI, 0.80-0.95). Intakes of carbohydrates from fruits, vegetables, and whole grains were positively associated with odds of healthy aging (ORs ranging from 1.11; 95% CI, 1.07-1.15 to 1.37; 95% CI, 1.20-1.57 per 5% energy increment). Additionally, intakes of total dietary fiber and fiber from fruits, vegetables, and cereals were associated with higher odds of healthy aging (ORs ranging from 1.07; 95% CI, 1.03-1.11 to 1.17; 95% CI, 1.13-1.22 per 1-SD increment). GL was positively associated with healthy aging, which was attenuated by dietary fiber adjustment. A higher GI (OR, 0.76; 95% CI, 0.67-0.87) and carbohydrate-to-fiber ratio (OR, 0.71; 95% CI, 0.62-0.81) were inversely associated with healthy aging when comparing extreme quintiles. There were positive associations for isocaloric replacements of refined carbohydrates, animal protein, total fat, or trans fats with high-quality carbohydrates (ORs ranging from 1.08; 95% CI, 1.01-1.16 to 1.16; 95% CI, 1.11-1.21).

Conclusions and Relevance

In this cohort study of women, intakes of high-quality carbohydrates and dietary fiber were associated with positive health status in older adulthood, suggesting that dietary carbohydrate quality may be an important determinant of healthy aging.

Dietary Factors and Cognitive Function: with a Focus on Subjective Cognitive Decline

PURPOSE OF THE REVIEW

Age-related cognitive decline is an important global challenge. Substantial evidence suggests that diet may prevent or delay cognitive aging. This narrative review examines recent literature on how dietary factors influence cognitive function, with a focus on subjective cognitive decline (SCD).

RECENT FINDINGS

Higher intakes of flavonoids, carotenoids, and plant-based protein were associated with lower odds of SCD. Berries, citrus fruits and juices, carotenoid-rich and green leafy vegetables, and beans/legumes were among the foods with the strongest inverse associations with SCD. Healthy dietary patterns, such as the Mediterranean and MIND diet, may be beneficial for maintaining subjective cognitive function. Healthy choice of diet may play a role in lowering the risk of late-life SCD.

Developing multifactorial dementia prediction models using clinical variables from cohorts in the US and Australia

Existing dementia prediction models using non-neuroimaging clinical measures have been limited in their ability to identify disease. This study used machine learning to re-examine the diagnostic potential of clinical measures for dementia. Data was sourced from the Australian Imaging, Biomarkers, and Lifestyle Flagship Study of Ageing (AIBL) and the Alzheimer's Disease Neuroimaging Initiative (ADNI). Clinical variables included 21 measures across medical history, hematological and other blood tests, and APOE genotype. Tree-based machine learning algorithms and artificial neural networks were used. APOE genotype was the best predictor of dementia cases and healthy controls. Our results, however, demonstrated that there are limitations when using publicly accessible cohort data that may limit the generalizability and interpretability of such predictive models. Future research should examine the use of routine APOE genetic testing for dementia diagnostics. It should also focus on clearly unifying data across clinical cohorts.

Herpes zoster and long-term risk of subjective cognitive decline

BACKGROUND

Herpes zoster (HZ), commonly known as "shingles," may contribute to cognitive decline through mechanisms such as neuroinflammation or direct neuronal injury. However, evidence on the longitudinal association between HZ and cognitive decline is conflicting and whether the risk differs by APOE ε4-carrier status has not been studied; prospective cohort studies on the association between HZ vaccination and cognitive decline are also lacking.

METHODS

We included 149,327 participants from three large cohorts-the Nurses' Health Study (NHS), NHSII, and Health Professionals Follow-Up Study (HPFS)-to prospectively examine the association between HZ and subsequent subjective cognitive decline (SCD). Poisson regression was used to estimate the multivariable-adjusted relative risk (MVRR) of a 3-unit increment in SCD score according to years since HZ compared with participants with no history of HZ.

RESULTS

Compared with individuals with no history of HZ, the MVRR (95% CI) of a 3-unit increment in SCD score was significantly and independently higher among individuals with a history of HZ, but the duration of time since HZ when the elevated risk of SCD was statistically significant differed among the cohorts. In NHS, HZ was associated with higher long-term risk of SCD; compared with individuals with no history of HZ, the MVRR (95% CI) of a 3-unit increment in SCD score was 1.14 (1.01, 1.32) for ≥ 13 years since HZ. In NHS II, HZ was associated with higher risk of SCD in both the short-term [MVRR 1.34 (1.18, 1.53) for 1-4 years] and long-term [MVRR 1.20 (1.08, 1.34) for ≥ 13 years since HZ]. In HPFS, an elevated risk of SCD was suggested across all time points. Among the subset of participants with information on APOE ε4, there was a suggestion that the association differed by APOE ε4 carrier status, but the results were not consistent between women and men. Among the subset of women with information on HZ vaccination, there was a suggestion that the long-term risk of SCD may be greater among women who were not vaccinated against HZ.

CONCLUSIONS

Data from three large independent cohorts of women and men showed that HZ was associated with higher long-term risk of SCD, and the risk may differ by APOE ε4-carrier status.

fNIRS as a biomarker for individuals with subjective memory complaints and MCI

INTRODUCTION

Identifying individuals at risk of developing dementia is crucial for early intervention. Mild cognitive impairment (MCI) and subjective memory complaints (SMCs) are considered its preceding stages. This study aimed to assess the utility of functional near-infrared spectroscopy (fNIRS) in identifying individuals with MCI and SMC.

METHODS

One hundred fifty-one participants were categorized into normal cognition (NC); amnestic MCI (aMCI); non-amnestic MCI (naMCI); and mild, moderate, and severe SMC groups. Task-related prefrontal hemodynamics were measured using fNIRS during a visual memory span task.

RESULTS

Results showed significantly lower oxyhemoglobin (HbO) levels in aMCI, but not in naMCI, compared to the NC. In addition, severe SMC had lower HbO levels than the NC, mild, and moderate SMC. Receiver operating characteristic analysis demonstrated 69.23% and 69.70% accuracy in differentiating aMCI and severe SMC from NC, respectively.

DISCUSSION

FNIRS may serve as a potential non-invasive biomarker for early detection of dementia.

HIGHLIGHTS

Only amnestic mild cognitive impairment (aMCI), but not non-amnestic MCI, showed lower oxyhemoglobin (HbO) than normal individuals. Reduced HbO was observed in those with severe subjective memory complaints (SMCs) compared to normal cognition (NC), mild, and moderate SMCs. Functional near-infrared spectroscopy measures were associated with performance in memory assessments. Prefrontal hemodynamics could distinguish aMCI and severe SMC from NC.

Brain structure, amyloid, and behavioral features for predicting clinical progression in subjective cognitive decline

As a potential preclinical stage of Alzheimer's dementia, subjective cognitive decline (SCD) reveals a higher risk of future cognitive decline and conversion to dementia. However, it has not been clear whether SCD status increases the clinical progression of older adults in the context of amyloid deposition, cerebrovascular disease (CeVD), and psychiatric symptoms. We identified 99 normal controls (NC), 15 SCD individuals who developed mild cognitive impairment in the next 2 years (P-SCD), and 54 SCD individuals who did not (S-SCD) from ADNI database with both baseline and 2-year follow-up data. Total white matter hyperintensity (WMH), WMH in deep (DWMH) and periventricular (PWMH) regions, and voxel-wise grey matter volumes were compared among groups. Furthermore, using structural equation modelling method, we constructed path models to explore SCD-related brain changes longitudinally and to determine whether baseline SCD status, age, and depressive symptoms affect participants' clinical outcomes. Both SCD groups showed higher baseline amyloid PET SUVR, baseline PWMH volumes, and larger increase of PWMH volumes over time than NC. In contrast, only P-SCD had higher baseline DWMH volumes and larger increase of DWMH volumes over time than NC. No longitudinal differences in grey matter volume and amyloid was observed among NC, S-SCD, and P-SCD. Our path models demonstrated that SCD status contributed to future WMH progression. Further, baseline SCD status increases the risk of future cognitive decline, mediated by PWMH; baseline depressive symptoms directly contribute to clinical outcomes. In conclusion, both S-SCD and P-SCD exhibited more severe CeVD than NC. The CeVD burden increase was more pronounced in P-SCD. In contrast with the direct association of depressive symptoms with dementia severity progression, the effects of SCD status on future cognitive decline may manifest via CeVD pathologies. Our work highlights the importance of multi-modal longitudinal designs in understanding the SCD trajectory heterogeneity, paving the way for stratification and early intervention in the preclinical stage. PRACTITIONER POINTS: Both S-SCD and P-SCD exhibited more severe CeVD at baseline and a larger increase of CeVD burden compared to NC, while the burden was more pronounced in P-SCD. Baseline SCD status increases the risk of future PWMH and DWMH volume accumulation, mediated by baseline PWMH and DWMH volumes, respectively. Baseline SCD status increases the risk of future cognitive decline, mediated by baseline PWMH, while baseline depression status directly contributes to clinical outcome.

Subjective cognitive concerns, APOE ε4, PTSD symptoms, and risk for dementia among older veterans

BACKGROUND

Posttraumatic stress disorder (PTSD) and traumatic brain injury (TBI) are associated with self-reported problems with cognition as well as risk for Alzheimer's disease and related dementias (ADRD). Overlapping symptom profiles observed in cognitive disorders, psychiatric disorders, and environmental exposures (e.g., head injury) can complicate the detection of early signs of ADRD. The interplay between PTSD, head injury, subjective (self-reported) cognitive concerns and genetic risk for ADRD is also not well understood, particularly in diverse ancestry groups.

METHODS

Using data from the U.S. Department of Veterans Affairs (VA) Million Veteran Program (MVP), we examined the relationship between dementia risk factors (APOE ε4, PTSD, TBI) and subjective cognitive concerns (SCC) measured in individuals of European (n = 140,921), African (n = 15,788), and Hispanic (n = 8,064) ancestry (EA, AA, and HA, respectively). We then used data from the VA electronic medical record to perform a retrospective survival analysis evaluating PTSD, TBI, APOE ε4, and SCC and their associations with risk of conversion to ADRD in Veterans aged 65 and older.

RESULTS

PTSD symptoms (B = 0.50-0.52, p < 1E-250) and probable TBI (B = 0.05-0.19, p = 1.51E-07 - 0.002) were positively associated with SCC across all three ancestry groups. APOE ε4 was associated with greater SCC in EA Veterans aged 65 and older (B = 0.037, p = 1.88E-12). Results of Cox models indicated that PTSD symptoms (hazard ratio [HR] = 1.13-1.21), APOE ε4 (HR = 1.73-2.05) and SCC (HR = 1.18-1.37) were positively associated with risk for ADRD across all three ancestry groups. In the EA group, probable TBI also contributed to increased risk of ADRD (HR = 1.18).

CONCLUSIONS

The findings underscore the value of SCC as an indicator of ADRD risk in Veterans 65 and older when considered in conjunction with other influential genetic, clinical, and demographic risk factors.

APOE Genotype Disclosure Influences Decisions About Future Planning but not Adoption of Healthy Lifestyle Changes in Cognitively Unimpaired Individuals

BACKGROUND

Studies have shown apolipoprotein E (APOE) genotype disclosure to be safe and well-tolerated in cognitively unimpaired (CU) older adults. This study aimed to examine the effect of the disclosure process on decisions about future directives and health behaviors in community-dwelling CU older adults from the Butler Alzheimer's Prevention Registry (BAPR).

METHODS

CU APOE E4 non-carriers (n = 106) and carriers (n = 80) aged 58-78 completed in-person psychological readiness screening to undergo APOE disclosure. Follow-up assessments were completed online 3 days, 6 weeks, and 6 months post-disclosure. The primary outcomes were future directives, dietary habits, and physical activity scores.

RESULTS

Disclosure was associated with decision making on future directives in E4 carriers (t = 3.59, P = .01) at 6 months compared to baseline, but not non-carriers. Family history of memory impairment, SCD endorsement, and education consistently predicted scores on future directives. A significant interaction between E4+ and SCD endorsement on future directive scores was noted (OR = 163.06, 9.5-2,799.8). E4 + carrier status was associated with physical activity (W = 60,148, P = .005) but not dietary habits scores.

CONCLUSIONS

Our findings indicate that disclosure led to a change in future directives but not protective health behaviors, specifically in E4 carriers. Future work will explore whether pairing disclosure with education about the role of lifestyle factors in AD risk and providing guidelines on making risk-lowering lifestyle modifications as an intervention approach leads to positive change.

Mid-life adherence to the Dietary Approaches to Stop Hypertension (DASH) diet and late-life subjective cognitive complaints in women

INTRODUCTION

Evidence is limited on the role of mid-life Dietary Approaches to Stop Hypertension (DASH) diet in late-life subjective cognitive complaints (SCCs).

METHODS

We included 5116 women (mean age in 1985-1991: 46 years) from the New York University Women's Health Study. SCCs were assessed from 2018 to 2020 (mean age: 79 years) by a 6-item questionnaire.

RESULTS

Compared to women in the bottom quartile of the DASH scores, the odds ratio (OR) for having two or more SCCs was 0.83 (95% confidence interval: 0.70-0.99) for women in the top quartile of DASH scores at baseline (P for trend = 0.019). The association was similar with multiple imputation and inverse probability weighting to account for potential selection bias. The inverse association was stronger in women without a history of cancer (P for interaction = 0.003).

DISCUSSION

Greater adherence to the DASH diet in mid-life was associated with lower prevalence of late-life SCCs in women.

Dietary protein intake in midlife in relation to healthy aging - results from the prospective Nurses' Health Study cohort

BACKGROUND

Protein intake plays an important role in maintaining the health status of older adults. However, few epidemiologic studies examined midlife protein intake in relation to healthy aging.

OBJECTIVES

The objective of this study was to evaluate the long-term role of dietary protein intake in healthy aging among female participants in the prospective Nurses' Health Study (NHS) cohort.

METHODS

We included 48,762 NHS participants aged <60 y in 1984. Total protein, animal protein, dairy protein (a subset of animal protein), and plant protein were derived from validated food frequency questionnaires. Healthy aging was defined as being free from 11 major chronic diseases, having good mental health, and not having impairments in either cognitive or physical function, as assessed in the 2014 or 2016 NHS participant questionnaires. We used multivariate logistic regression adjusted for lifestyle, demographics, and health status to estimate the odds ratios (ORs) and 95% confidence intervals for protein intake in relation to healthy aging.

RESULTS

A total of 3721 (7.6%) NHS participants met our healthy aging definition. Protein intake was significantly associated with higher odds of healthy aging. The ORs (95% confidence intervals) per 3%-energy increment with healthy aging were 1.05 (1.01, 1.10) for total protein, 1.07 (1.02, 1.11) for animal protein, 1.14 (1.06, 1.23) for dairy protein, and 1.38 (1.24, 1.54) for plant protein. Plant protein was also associated with higher odds of absence of physical function limitations and good mental status. In substitution analyses, we observed significant positive associations for the isocaloric replacement of animal or dairy protein, carbohydrate, or fat with plant protein (ORs for healthy aging: 1.22-1.58 for 3% energy replacement with plant protein).

CONCLUSIONS

Dietary protein intake, especially plant protein, in midlife, is associated with higher odds of healthy aging and with several domains of positive health status in a large cohort of female nurses.

Subjective cognitive decline exhibits alterations of resting-state phase-amplitude coupling in precuneus

OBJECTIVE

Subjective cognitive decline (SCD) is associated with increased risks for progressing to Alzheimer's disease (AD). This study aimed to investigate phase-amplitude coupling (PAC) in individuals with SCD and healthy controls (HCs) in the baseline year and determined the predictability of cognitive changes in the clinical follow-up.

METHODS

Resting-state magnetoencephalographic signals in 29 HCs and 23 SCD subjects were recorded in the baseline year. The parahippocampal gyrus, posterior cingulate cortex and precuneus were selected as regions of interest (ROIs). Based on the grand-averaged comodulograms, delta-beta, delta-gamma and theta-gamma PAC values were extracted from each ROI.

RESULTS

Compared with the HCs, the SCD group showed decreased theta-gamma PAC in the precuneus. Theta-gamma PAC of the left precuneus was associated with SCD severity and performance of immediate recall in the baseline year. The SCD group was followed for 3 years and divided into SCD-Stable and SCD-Decline groups based on scores of Mini-Mental State Examination. No significant differences in PAC of the baseline year were found between SCD-Stable and SCD-Decline groups.

CONCLUSIONS

The SCD group demonstrated reduced theta-gamma PAC in the precuneus.

SIGNIFICANCE

Subjective perception of cognitive decline is reflected by objective alterations of brain function.

Association Between Bowel Movement Pattern and Cognitive Function: Prospective Cohort Study and a Metagenomic Analysis of the Gut Microbiome

BACKGROUND AND OBJECTIVES

Little is known regarding the association between intestinal motility patterns and cognitive function in individuals who are baseline cognitively healthy. The gut microbiome may contribute to the association. We examined the association between bowel movement (BM) pattern and cognitive function and explored the role of the gut microbiome in explaining this association.

METHODS

In this prospective study, we leveraged 3 cohort studies, Nurses' Health Study (NHS), NHSII, and Health Professionals Follow-Up Study (HPFS). Participants reported BM frequency and subjective cognitive function. In a subset of NHSII participants, we assessed cognitive function using an objective neuropsychological battery. We profiled the gut microbiome in a subset of participants using whole-genome shotgun metagenomics. General linear models, Poisson regression, and logistic regression were used to quantify the association of BM frequency with different cognitive measurements.

RESULTS

We followed 112,753 men and women (women: 87.6%) with a mean age of 67.2 years at baseline (NHS: 76 years, NHSII: 59 years, HPFS: 75 years) for a median follow-up of 4 years (NHSII and HPFS: 4 years, NHS: 2 years). Compared with those with BM once daily, participants with BM frequency every 3+ days had significantly worse objective cognitive function, equivalent to 3.0 (95% confidence interval [CI],1.2-4.7) years of chronological cognitive aging. We observed similar J-shape dose-response relationships of BM frequency with the odds of subjective cognitive decline and the likelihood of having more subsequent subjective cognitive complaints (both p nonlinearity < 0.001). BM frequencies of every 3+ days and ≥twice/day, compared with once daily, were associated with the odds ratios of subjective cognitive decline of 1.73 (95% CI 1.60-1.86) and 1.37 (95% CI 1.33-1.44), respectively. BM frequency and subjective cognitive decline were significantly associated with the overall gut microbiome configuration (both p < 0.005) and specific microbial species in the 515 participants with microbiome data. Butyrate-producing microbial species were depleted in those with less frequent BM and worse cognition, whereas a higher abundance of proinflammatory species was associated with BM frequency of ≥twice/day and worse cognition.

DISCUSSION

Lower BM frequency was associated with worse cognitive function. The gut microbial dysbiosis may be a mechanistic link underlying the association.

Subjective Cognitive Decline in Women with Features Suggestive of Prodromal Parkinson's Disease

BACKGROUND

Cognitive deficits can be present in the prodromal phase of Parkinson's disease (PD). Subjective cognitive decline (SCD) may contribute to identifying individuals with prodromal PD.

OBJECTIVE

The objective of this study was to examine whether SCD is more likely to be present in women with features suggestive of prodromal PD compared with women without these features.

METHODS

The study population comprised 12,427 women from the Nurses' Health Study selected to investigate prodromal PD. Prodromal and risk markers of PD were assessed via self-administered questionnaires. We evaluated the association of hyposmia, constipation, and probable rapid eye movement sleep behavior disorder, three major features of prodromal PD, with SCD, adjusting for age, education, body mass index, physical activity, smoking, alcohol, caffeine intake, and depression. We also explored whether SCD was associated with the probability of prodromal PD and conducted additional analyses using data from neurocognitive tests.

RESULTS

Women experiencing the three examined nonmotor features had the worst mean SCD score and the highest odds of poor subjective cognition (odds ratio [OR] = 1.78; 95% confidence interval [CI], 1.29-2.47). This association persisted when women with objective cognitive deficits were excluded from analyses. SCD was also more common in women with a probability of prodromal PD ≥0.80, particularly among those aged younger than 75 years (OR of poor subjective cognition = 6.57 [95% CI, 2.43-17.77]). These observations were consistent with the results from analyses using neurocognitive tests, where a worse global cognitive performance was observed among women with three features.

CONCLUSIONS

Our study suggests that self-perceived cognitive decline can be present during the prodromal phase of PD. © 2023 International Parkinson and Movement Disorder Society.

Cognitive and behavioral abnormalities in individuals with Alzheimer’s disease, mild cognitive impairment, and subjective memory complaints

In this study, we investigated the ability of commonly used neuropsychological tests to detect cognitive and functional decline across the Alzheimer’s disease (AD) continuum. Moreover, as preclinical AD is a key area of investigation, we focused on the ability of neuropsychological tests to distinguish the early stages of the disease, such as individuals with Subjective Memory Complaints (SMC). This study included 595 participants from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) dataset who were cognitively normal (CN), SMC, mild cognitive impairment (MCI; early or late stage), or AD. Our cognitive measures included the Rey Auditory Verbal Learning Test (RAVLT), the Everyday Cognition Questionnaire (ECog), the Functional Abilities Questionnaire (FAQ), the Alzheimer’s Disease Assessment Scale–Cognitive Subscale (ADAS-Cog), the Montreal Cognitive Assessment scale (MoCA), and the Trail Making test (TMT-B). Overall, our results indicated that the ADAS-13, RAVLT (learning), FAQ, ECog, and MoCA were all predictive of the AD progression continuum. However, TMT-B and the RAVLT (immediate and forgetting) were not significant predictors of the AD continuum. Indeed, contrary to our expectations ECog self-report (partner and patient) were the two strongest predictors in the model to detect the progression from CN to AD. Accordingly, we suggest using the ECog (both versions), RAVLT (learning), ADAS-13, and the MoCA to screen all stages of the AD continuum. In conclusion, we infer that these tests could help clinicians effectively detect the early stages of the disease (e.g., SMC) and distinguish the different stages of AD.

Cognitive and biological effects of citrus phytochemicals in subjective cognitive decline: a 36-week, randomized, placebo-controlled trial

Background

Auraptene (AUR) and naringenin (NAR) are citrus-derived phytochemicals that influence several biological mechanisms associated with cognitive decline, including neuronal damage, oxidative stress and inflammation. Clinical evidence of the efficacy of a nutraceutical with the potential to enhance cognitive function in cohorts at risk of cognitive decline would be of great value from a preventive perspective. The primary aim of this study is to determine the cognitive effects of a 36-week treatment with citrus peel extract standardized in levels of AUR and NAR in older adults experiencing subjective cognitive decline (SCD). The secondary aim is to determine the effects of these phytochemicals on blood-based biomarkers indicative of neuronal damage, oxidative stress, and inflammation.

Methods

Eighty older persons with SCD will be recruited and randomly assigned to receive the active treatment (400 mg of citrus peel extract containing 0.1 mg of AUR and 3 mg of NAR) or the placebo at a 1:1 ratio for 36 weeks. The primary endpoint is a change in the Repeatable Battery for the Assessment of Neuropsychological Status score from baseline to weeks 18 and 36. Other cognitive outcomes will include changes in verbal and nonverbal memory, attention, executive and visuospatial functions. Blood samples will be collected from a consecutive subsample of 60 participants. The secondary endpoint is a change in interleukin-8 levels over the 36-week period. Other biological outcomes include changes in markers of neuronal damage, oxidative stress, and pro- and anti-inflammatory cytokines.

Conclusion

This study will evaluate whether an intervention with citrus peel extract standardized in levels of AUR and NAR has cognitive and biological effects in older adults with SCD, facilitating the establishment of nutrition intervention in people at risk of cognitive decline.

Trial registration

The trial is registered with the United States National Library of Medicine at the National Institutes of Health Registry of Clinical Trials under the code NCT04744922 on February 9^th, 2021 (https://www.clinicaltrials.gov/ct2/show/NCT04744922).

Long-term intake of total energy and fat in relation to subjective cognitive decline

Diet is one of the modifiable risk factors for cognitive decline. However, human studies on total energy intake and cognitive function have remained limited and studies on fat intake and cognitive decline have been inconclusive. We aimed to examine prospectively the associations between long-term intakes of total energy and fat with subsequent subjective cognitive decline (SCD). A total of 49,493 women from the Nurses' Health Study and 27,842 men from the Health Professionals Follow-up Study were followed for over 20 years. Average dietary intake was calculated based on repeated food frequency questionnaires (SFFQs), and Poisson regression was used to evaluate associations. Higher total energy intake was significantly associated with greater odds of SCD in both cohorts. Comparing the highest with lowest quintiles of total energy intake, the pooled multivariable-adjusted ORs (95% CIs) for a 3-unit increment in SCD, corresponding to poor versus normal SCD, was 2.77 (2.53, 2.94). Each 500 kcal/day greater intake of total energy was associated with 48% higher odds of SCD. Intakes of both total fat and total carbohydrate appeared to contribute to the positive association between total energy intake and SCD although for the same percent of energy, the association was stronger for total fat. In conclusion, higher intakes of total energy, total fat, and total carbohydrate were adversely associated with SCD. Whether these associations are causal is unclear and deserves further investigation.

Gut Microbiota and Subjective Memory Complaints in Older Women

BACKGROUND

Epidemiological studies that investigate alterations in gut microbial composition associated with cognitive dysfunction are limited.

OBJECTIVE

To examine the association between the gut microbiota and subjective memory complaints (SMCs), a self-reported, validated indicator of cognitive dysfunction.

METHODS

In this cross-sectional study of 95 older women selected from the New York University Women's Health Study (NYUWHS), we characterized the gut microbial composition using 16S rRNA gene sequencing. We estimated odds ratio (OR) from beta regression which approximates the ratio of mean relative abundances of individual bacterial taxon from phylum to genus levels by binary (2+ versus < 2) and continuous SMCs.

RESULTS

Women reporting 2 or more SMCs had higher relative abundances of genus Holdemania and family Desulfovibrionaceae compared with those reporting one or no complaint. Compared with women with < 2 SMCs, the relative abundances of Holdemania and family Desulfovibrionaceae were 2.09 times (OR: 2.09, 95% confidence interval [CI]: 1.38-3.17) and 2.10 times (OR: 2.10, 95% CI: 1.43-3.09) higher in women with 2+ SMCs, respectively (false discovery rate (FDR)-adjusted p = 0.038 and 0.010, respectively). A dose-response association was observed for genus Sutterella and family Desulfovibrionaceae. Every one-unit increase in SMCs was associated with 25% and 27% higher relative abundances of Sutterella (OR: 1.25; 95% CI: 1.11-1.40) and Desulfovibrionaceae (OR: 1.27; 95% CI: 1.13-1.42), respectively (FDR-adjusted p = 0.018 and 0.006, respectively).

CONCLUSION

Our findings support an association between alterations in the gut bacterial composition and cognitive dysfunction.

Long-term diet quality and its change in relation to late-life subjective cognitive decline

BACKGROUND

Evidence regarding the role of diet quality, especially its change, in subjective cognitive decline (SCD) is scarce.

OBJECTIVES

We aimed to examine associations of long-term diet quality scores, including the Alternate Mediterranean Diet (AMED), Dietary Approaches to Stop Hypertension (DASH), and Alternate Healthy Eating Index 2010 (AHEI-2010), with SCD in the Nurses' Health Study.

METHODS

We followed 49,493 female registered nurses (mean age in 1984: 48 y) from 1984 to 2014. Diet scores were derived from 7 repeated FFQs in 1984, 1986, and every 4 y afterward until 2006. Self-reported SCD was assessed in 2012 and 2014 by a 7-item questionnaire on memory and cognition changes. Categorical SCD score was classified as "none" (0 points, 40.8%), "moderate" (0.5-2.5 points, 46.9%), and "severe" (3-7 points, 12.3%).

RESULTS

Multinomial and linear regression models were adjusted for total calorie intake, demographic characteristics, lifestyle, and clinical factors. Comparing the top with the bottom quintiles of AMED, DASH, and AHEI-2010, multivariable-adjusted ORs (95% CIs) for severe SCD compared with none were 0.57 (0.51, 0.64), 0.61 (0.55, 0.68), and 0.81 (0.73, 0.90), respectively. Similar associations remained for the 3 diet indexes evaluated 28 y before SCD assessment. Compared with participants with the lowest diet quality tertiles in both remote and recent years, the lowest odds of severe SCD were observed among those who maintained the highest diet quality tertiles over time, with 40%, 32%, and 20% lower odds of severe SCD for AMED, DASH, and AHEI-2010, respectively. Moreover, the odds of severe SCD were lower among those with improved diets over time; for each SD higher in diet quality change, the reductions in risk were 11% for AMED, 5% for DASH, and 3% for AHEI-2010, respectively.

CONCLUSIONS

Our findings support beneficial roles of long-term adherence to, and improvement in, healthy dietary patterns for the maintenance of subjective cognition in women.

Long-term Dietary Flavonoid Intake and Subjective Cognitive Decline in US Men and Women

OBJECTIVE

To prospectively examine the associations between long-term dietary flavonoids and subjective cognitive decline (SCD).

METHODS

We followed 49,493 women from the Nurses' Health Study (NHS) (1984-2006) and 27,842 men from the Health Professionals Follow-Up Study (HPFS) (1986-2002). Poisson regression was used to evaluate the associations between dietary flavonoids (flavonols, flavones, flavanones, flavan-3-ols, anthocyanins, polymeric flavonoids, and proanthocyanidins) and subsequent SCD. For the NHS, long-term average dietary intake was calculated from 7 repeated semiquantitative food frequency questionnaires (SFFQs), and SCD was assessed in 2012 and 2014. For the HPFS, average dietary intake was calculated from 5 repeated SFFQs, and SCD was assessed in 2008 and 2012.

RESULTS

Higher intake of total flavonoids was associated with lower odds of SCD after adjustment for age, total energy intake, major nondietary factors, and specific dietary factors. In a comparison of the highest vs the lowest quintiles of total flavonoid intake, the pooled multivariable-adjusted odds ratio (OR) of 3-unit increments in SCD was 0.81 (95% confidence interval [CI] 0.76, 0.89). In the pooled results, the strongest associations were observed for flavones (OR 0.62 [95% CI 0.57, 0.68]), flavanones (0.64 [0.58, 0.68)]), and anthocyanins (0.76 [0.72, 0.84]) (p trend <0.001 for all groups). The dose-response curve was steepest for flavones, followed by anthocyanins. Many flavonoid-rich foods such as strawberries, oranges, grapefruits, citrus juices, apples/pears, celery, peppers, and bananas, were significantly associated with lower odds of SCD.

CONCLUSION

Our findings support a benefit of higher flavonoid intakes for maintaining cognitive function in US men and women.

Long-term dietary protein intake and subjective cognitive decline in US men and women

BACKGROUND

Diet is one of the modifiable risk factors for cognitive decline. However, studies on dietary protein intake and cognitive decline have remained limited and inconclusive.

OBJECTIVES

In this study, we aimed to investigate the associations between long-term dietary protein intake and subsequent subjective cognitive decline (SCD).

METHODS

We included 49,493 women from the Nurses' Health Study (NHS) (1984-2006) and 27,842 men from the Health Professionals Follow-up Study (HPFS) (1986-2002). For the NHS, average dietary intake was calculated from 7 repeated semi-quantitative FFQs (SFFQs), and SCD was assessed in 2012 and 2014. For the HPFS, average dietary intake was calculated from 5 repeated SFFQs, and SCD was assessed in 2008 and 2012. Poisson regression was used to examine the associations between dietary protein, amino acids, and various protein food sources with subsequent SCD.

RESULTS

Higher protein intake compared with total carbohydrates was associated with lower odds of SCD. When substituting 5% energy from protein for the equivalent percentage of energy from total carbohydrates, the pooled multivariable-adjusted ORs (95% CIs) were 0.89 (0.85, 0.94) for total protein, 0.89 (0.84, 0.94) for animal protein, and 0.74 (0.62, 0.88) for plant protein. When substituting 5% of energy from animal protein with plant protein, the OR was 0.84 (95% CI: 0.72, 0.97). For protein food sources, higher intakes of beans/legumes, fish, and lean poultry were significantly associated with lower odds of SCD, but higher intake of hotdogs was associated with higher odds of SCD.

CONCLUSIONS

Higher protein intake was associated with lower odds of SCD when compared isocalorically with carbohydrate. Plant protein sources were also associated with lower odds when compared with animal protein sources. Our findings suggest that adequate protein intake, and choices of protein sources could play a role in the maintenance of cognition and should be studied further.

Anticholinergic/Sedative Drug Burden and Subjective Cognitive Decline in Older Adults at Risk of Alzheimer's Disease

BACKGROUND

Anticholinergic/sedative drug use, measured by the Drug Burden Index (DBI), has been linked to cognitive impairment in older adults. Subjective cognitive decline (SCD) may be among the first symptoms patients with Alzheimer's disease (AD) experience. We examined whether DBI values are associated with SCD in older adults at risk of AD. We hypothesized that increased DBI would be associated with greater SCD at older ages.

METHOD

Two-hundred-six community-dwelling, English-speaking adults (age = 65 ± 9 years) at risk of AD (42% apolipoprotein ε4 carriers; 78% with AD family history) were administered a single question to ascertain SCD: "Do you feel like your memory is becoming worse?" Response options were "No"; "Yes, but this does not worry me"; and "Yes, this worries me." DBI values were derived from self-reported medication regimens using older adult dosing recommendations. Adjusting for relevant covariates (comorbidities and polypharmacy), we examined independent effects of age and DBI on SCD, as well as the moderating effect of age on the DBI-SCD association at mean ± 1 SD of age.

RESULTS

Both SCD and anticholinergic/sedative drug burden were prevalent. Greater drug burden was predictive of SCD severity, but age alone was not. A significant DBI*Age interaction emerged with greater drug burden corresponding to more severe SCD among individuals age 65 and older.

CONCLUSION

Anticholinergic/sedative drug exposure was associated with greater SCD in adults 65 and older at risk for AD. Longitudinal research is needed to understand if this relationship is a pre-clinical marker of neurodegenerative disease and predictive of future cognitive decline.

Aging with multiple sclerosis: A longitudinal study of physical function, mental health, and memory in two cohorts of US women

BACKGROUND

It is unknown how individuals with multiple sclerosis (MS) age compared to unaffected peers.

OBJECTIVES

The objective of the study is to describe the impact of MS on health and functioning in aging women.

METHODS

We used 10-item Physical Functioning Scale (PF10) scores (from the Short Form-36 (SF-36)) and other indicators of general, physical, mental health, and memory collected repeatedly over 25 years with self-administered questionnaires among participants in the Nurses' Health Study (n = 121,700 recruited at ages 30-55) and Nurses' Health Study II (n = 116,429 recruited at ages 25-42) to compare women with MS (n = 733) to unaffected peers in their health and disability, and describe/quantify the burden of aging with MS.

RESULTS

Women with MS had a consistently lower PF10 by 0.9-1.7 standard deviations with greater overall variability than unaffected women. PF10-scores gradually decreased with increasing age in both groups, but MS cases declined 3-4 times faster in midlife, while decline was similar in old age. The physical function score of 45-year-old women with MS was comparable to that of 75-year-old unaffected women; 70-year-old women with MS scored similarly to 85-year-old unaffected women. MS cases also reported worse health/more disability throughout adulthood on the other indicators.

CONCLUSION

The age-related decline in physical health is accelerated by 15-30 years in MS patients compared to unaffected peers.

Predictors of Subjective Cognitive Decline Among People With Diabetes: Data From the Behavioral Risk Factor Surveillance System

PURPOSE

The purpose of this study was to examine the prevalence of subjective cognitive decline (SCD) and SCD-related functional limitations among people with diabetes and to identify socioeconomic and comorbidity risk factors associated with SCD.

METHODS

This study analyzed data from the 2017 Behavioral Risk Factor Surveillance System (BRFSS) with background variables (race, gender, education, and age), health-related factors (self-rated health, BMI, insurance, and comorbid conditions), and health behaviors (smoking, exercise, alcohol consumption) entered simultaneously to estimate logistic regression models of SCD.

RESULTS

Within the sample (n = 5263 adults with diabetes), 48% were age ≥65 years; 50% were male; 55% were non-Hispanic White; and of the 15% who reported having SCD, 57% had functional limitations. Increased odds of reporting SCD were observed among individuals who were Hispanic (odds ratio [OR] = 2.21, P < .001), male (OR = 1.47, P < .01), depressed (OR = 3.85, P < .001), or had arthritis (OR = 1.43, P < .03). Participants with better self-rated health had a reduced likelihood of SCD (OR = 0.51, P < .001).

CONCLUSIONS

Health care providers should assess high-risk patients for self-rated cognitive dysfunction and offer early interventions.

Vitamin D Levels, APOE Allele, and MRI Volumetry Assessed by NeuroQuant in Norwegian Adults with Cognitive Symptoms

BACKGROUND

Allele ɛ4 of the apolipoprotein (APOE∈4) gene is the strongest known genetic risk factor for late-onset sporadic Alzheimer's disease. A possible relationship between vitamin D and APOE is not yet clear.

OBJECTIVE

In this exploratory, cross-sectional study, we examined the association between serum levels of 25-hydroxyvitamin D [25(OH)D] and brain volumes and the associations of both serum levels of 25(OH)D and APOE polymorphism to brain volumes in 127 persons (mean age 66 years) with cognitive symptoms.

METHODS

All subjects were examined with fully automated software for MRI volumetry, NeuroQuant.

RESULTS

After adjustment for relevant covariates, higher serum 25(OH)D levels were associated with greater volumes of cortical gray matter on both left (p = 0.02) and right (p = 0.04) sides. When both 25(OH)D levels and APOE genotype were used as the main covariates, no significant associations were found between vitamin D level and brain volume in any of the 11 brain regions. In adjusted models, only homozygous but not heterozygous APOE∈4 allele carriers had significantly larger inferior lateral ventricles (p = 0.003) and smaller hippocampal volume (p = 0.035) than those without ɛ4. Homozygous APOE∈4 carriers also had significantly higher vitamin D levels (p = 0.009) compared to persons without the APOE∈4 allele.

CONCLUSION

Higher vitamin D levels might have a preserving effect on cortical grey matter volume.

Long-Term Intake of Dietary Carotenoids Is Positively Associated with Late-Life Subjective Cognitive Function in a Prospective Study in US Women

BACKGROUND

A protective association of dietary carotenoids with cognitive function has been suggested, but most studies have been relatively small with limited periods of follow-up.

OBJECTIVES

We examined prospectively long-term intakes of carotenoids in relation to subjective cognitive function (SCF), a self-reported, validated indicator of cognitive dysfunction.

METHODS

Among 49,493 female registered nurses with a mean age of 48 y in 1984, we used multinomial logistic regression to estimate the ORs and 95% CIs relating intakes of carotenoids to self-reported SCF in 2012 and 2014. Mean intakes of carotenoids were calculated from 7 repeated FFQs collected in 1984, 1986, and every 4 y afterwards until 2006. Self-reported SCF was assessed by a 7-item questionnaire on changes in memory and cognition; validity was supported by strong associations with Apolipoprotein E (APOE) ε4 genotype and concurrent cognitive function and cognitive decline measured by telephone-based neuropsychological tests. The mean values of scores assessed in 2012 and 2014 were categorized as "good" (0 points, 40.8%), "moderate" (0.5-2.5 points, 46.9%), and "poor" (3-7 points, 12.3%).

RESULTS

Higher intake of total carotenoids was associated with substantially lower odds of moderate or poor cognitive function after controlling for other dietary and nondietary risk factors and total energy intake. Comparing the top with the bottom quintile of total carotenoids, the multivariable ORs were 0.86 (95% CI: 0.80, 0.93; P-trend < 0.001) for moderate SCF and 0.67 (95% CI: 0.60, 0.75; P-trend < 0.001) for poor SCF. This lower OR was also seen for carotenoids consumed 28 y before SCF assessment. Similar associations were found for total β-carotene, dietary β-carotene, α-carotene, lycopene, lutein + zeaxanthin, and β-cryptoxanthin. The significant associations for β-cryptoxanthin, lycopene, and lutein + zeaxanthin persisted after mutual adjustment for each other.

CONCLUSIONS

Our findings support a long-term beneficial role of carotenoid consumption on cognitive function in women.

Subjective Cognitive Impairment in 55-65-Year-Old Adults Is Associated with Negative Affective Symptoms, Neuroticism, and Poor Quality of Life

Although subjective cognitive impairment (SCI) is increasingly recognized clinically and in research as a risk factor for mild cognitive impairment and dementia (particularly Alzheimer’s disease), it is etiologically heterogeneous and potentially treatable. Compared to mild cognitive impairment and Alzheimer’s disease, SCI however remains poorly characterized with debate continuing regarding its clinical relevance. The primary aim of this study was to improve the characterization of SCI within the general public by investigating functions sometimes omitted clinically or in research, namely visual attention-related information processing speed (RT) and its intra-individual variability (IIV_RT), general cognition, depression, anxiety, memory, quality of life (QOL), and neuroticism. Compared to individuals without SCI, those with SCI were more likely to reveal higher scores of anxiety, depression, and neuroticism and poorer perceived physical, psychological, and environmental QOL. Within-group analysis identified no significant relationships between any of the above variables for the non-SCI group whereas for the SCI group, poorer Cognitive Change Index scores were significantly correlated with slower RT, raised IIV_RT, poorer memory, negative affective symptoms, higher neuroticism scores, and poorer QOL. This indicates that reports of perceived memory changes in SCI can also be associated with other characteristics, namely objectively measured detrimental change in other aspects of brain function and behavior. This outcome emphasizes the importance of a multi-function approach to characterizing and understanding SCI. Thus, although the effect of RT and IIV_RT is not strong enough to differentiate SCI from non-SCI at group level, slowing and raised IIV_RT do appear to characterize some people with SCI.

Apolipoprotein E ε4 Allele Is Associated with Reduced Retention of the "Where" Memory Component in Cognitively Intact Older Adults

OBJECTIVE

The present study investigated the effect of the apolipoprotein E (ApoE) ε4 allele on the four memory components (i.e., who, when, where, and what) among cognitively intact older adults.

METHODS

Participants comprised 47 cognitively intact older adults, who were classified into 2 groups based on the presence or absence of at least 1 ApoE ε4 allele. All participants completed standardized neuropsychological tests, including the Logical Memory subtest of the Wechsler Memory Scale-III with a revised scoring method.

RESULTS

The results revealed that recollection for each component followed a pattern of who > what > when = where. Furthermore, a significant group-by-component-by-condition interaction indicated that the presence of the ApoE ε4 allele resulted in a disproportionately detrimental effect on the where component retention in the verbal episodic memory task; this finding was significantly correlated with hippocampal volumes.

CONCLUSION

These results highlighted the importance of evaluating the subcomponents of verbal episodic memory to detect subtle cognitive differences related to ApoE ε4 status, which could help elucidate the mechanism behind the cascades caused by ApoE ε4 in the trajectories of cognitive aging.

Longitudinal study of self-reported hearing loss and subjective cognitive function decline in women

INTRODUCTION

We investigated the relation between self-reported hearing loss and risk of subjective cognitive function (SCF) decline among women.

METHODS

We conducted a longitudinal study of 20,193 women in the Nurses' Health Study aged ≥66 years who reported their hearing status and had no subjective cognitive concerns in 2012. SCF scores were assessed by a 7-item questionnaire in 2012 and 2014. SCF decline was defined as a new report of at least one cognitive concern during follow-up.

RESULTS

Self-reported hearing loss was associated with higher risk of SCF decline. Compared with women with no hearing loss, the multivariable-adjusted odds ratios (95% confidence interval) for incident SCF score ≥1 were 1.35 (1.25, 1.47), 1.39 (1.24, 1.56), and 1.40 (1.21, 1.75) among women with mild, moderate, and severe hearing loss, respectively. Recent progression of hearing loss was associated with even higher risk.

DISCUSSION

Self-reported hearing loss was associated with higher risk of incident subjective cognitive function decline in women.

Consumption of Nuts at Midlife and Healthy Aging in Women

BACKGROUND

Nut consumption may reduce age-related diseases and lead to better health and well-being in aging. Many conditions of aging develop over decades, and thus earlier lifestyle factors may particularly influence later health.

METHODS

In 1998 and 2002, we administered food frequency questionnaires to assess nut consumption (peanuts, walnuts, and other nuts and peanut butter) in women in the Nurses' Health Study in their 50 s/early 60 s. In 2012, those who survived beyond 65 years with no chronic diseases, no reported memory impairment, no physical disabilities, and intact mental health were considered "healthy agers." We used multivariable logistic regression to estimate odds ratios for healthy versus usual aging, controlled for sociodemographic, behavioral, dietary, and other potential confounding factors.

RESULTS

Of 33,931 participants at midlife, 16% became "healthy agers." After age adjustment, we observed a significant association between total nut consumption at midlife and higher odds of healthy aging, with strongest associations observed excluding peanut butter (odds ratio (OR) = 1.46, 95% confidence interval (CI) 1.32-1.62, ≥3 servings/week versus none). Findings were attenuated after further control for covariates, including overall diet quality (OR = 1.14, 95% CI 1.02-1.28, P trend = 0.05). For nut types, we found statistically significantly higher odds of healthy aging across peanuts, walnuts, and other nuts after age adjustment. After full control for confounders, only walnut consumption remained associated with healthy aging (P trend = 0.0001); for example, the OR was 1.20 (95% CI 1.00-1.44) for ≥2 servings/week versus none.

CONCLUSIONS

Women consuming nuts at midlife have a greater likelihood of overall health and well-being at older ages. Nut consumption may represent a simple intervention to explore and promote healthy aging.

Linking APOE-ε4, blood-brain barrier dysfunction, and inflammation to Alzheimer's pathology

The APOE-ε4 genotype is a risk factor for late-onset Alzheimer's disease (AD) as well as vascular pathology. Given the increased risk of blood-brain barrier (BBB) dysfunction and inflammation among APOE-ε4 carriers, we aimed to examine whether BBB dysfunction and inflammation contribute to the relationship between APOE and AD key pathologies, as measured in the cerebrospinal fluid (CSF). We applied bootstrapped regression and path analyses involving Q-albumin CSF/plasma ratio (a BBB/blood-CSF barrier function marker), interleukins (IL-1β, IL-6, and IL-12p70; inflammation markers), and CSF p-Tau₁₈₁ and amyloid-β_1-42 (AD pathology markers) of 97 participants (aged 38-83 years) from a university memory clinic. Our results showed that relationship between BBB dysfunction and AD pathology is modulated by IL-6 and these associations appear to be driven by the APOE-ε4 genotype. This suggests that APOE-ε4-related vascular factors are also part of the pathway to AD pathology, in synergy with an elevated immune response, and could become targets for trials focused on delaying AD.

Distinct neural correlates of episodic memory among apolipoprotein E alleles in cognitively normal elderly

The apolipoprotein E (APOE) ε4 and ε2 alleles are acknowledged genetic factors modulating Alzheimer's disease (AD) risk and episodic memory (EM) deterioration in an opposite manner. Mounting neuroimaging studies describe EM-related brain activity differences among APOE alleles but remain limited in elucidating the underlying mechanism. Here, we hypothesized that the APOE ε2, ε3, and ε4 alleles have distinct EM neural substrates, as a manifestation of degeneracy, underlying their modulations on EM-related brain activity and AD susceptibility. To test the hypothesis, we identified neural correlates of EM function by correlating intrinsic hippocampal functional connectivity networks with neuropsychological EM performances in a voxelwise manner, with 129 cognitively normal elderly subjects (36 ε2 carriers, 44 ε3 homozygotes, and 49 ε4 carriers). We demonstrated significantly different EM neural correlates among the three APOE allele groups. Specifically, in the ε3 homozygotes, positive EM neural correlates were characterized in the Papez circuit regions; in the ε4 carriers, positive EM neural correlates involved the lateral temporal cortex, premotor cortex/sensorimotor cortex/superior parietal lobule, and cuneus; and in the ε2 carriers, negative EM neural correlates appeared in the bilateral frontopolar, posteromedial, and sensorimotor cortex. Further, in the ε4 carriers, the interaction between age and EM function occurred in the temporoparietal junction and prefrontal cortex. Our findings suggest that the underlying mechanism of APOE polymorphism modulations on EM function and AD susceptibility is genetically related to the neural degeneracy of EM function across APOE alleles.

Anxiety correlates with cortical surface area in subjective cognitive decline: APOE ε4 carriers versus APOE ε4 non-carriers

Background

Subjective cognitive decline (SCD) is characterized by self-reported cognitive deficits without measurable cognitive impairment. It has been suggested that individuals with SCD exhibited brain structural alterations in widespread cortical thinning or gray matter loss in the medial temporal and frontotemporal regions. Apolipoprotein E (APOE) ε4 allele is thought to be a genetic marker associated with risk of SCD. Neuropsychiatric symptoms may provide insight in detecting higher-risk elders for early Alzheimer’s disease as well. Therefore, we aim to explore the characteristics of brain morphology in SCD and to determine whether it is influenced by APOE ε4 as well as neuropsychiatric symptoms in SCD.

Methods

A total of 138 cognitively normal older individuals from the SILCODE cohort underwent a clinical interview, neuropsychological assessments, a blood test, and MRI. A two-sample t-test was used to examine the cortex volume and bilateral cortical surface area alterations between SCD (n = 65) and controls (n = 73). A general linear model analysis was used to test for both main and interaction effects of clinical phenotype (SCD vs. controls) and APOE on global and regional cortex volume and bilateral cortical surface area and thickness. A multiple linear regression analysis was conducted to determine the effects of the APOE genotype on the relationships between morphometric features and neuropsychiatric symptoms in SCD.

Results

Compared with controls, individuals with SCD showed decreased total cortical volumes and cortical surface area. SCD APOE ε4 carriers showed additive reduction in the right cortical surface area. The evaluation scores of anxiety symptoms were negatively associated with the right cortical surface area in SCD APOE 4 non-carriers.

Conclusions

Individuals with SCD had an altered cortical surface area, and APOE genotype and anxiety symptoms are modified factors on the cortical surface area decrease in SCD.

Trial registration

ClinicalTrials.gov (Identifier: NCT03370744). Registered 15 March 2017.

Electronic supplementary material

The online version of this article (10.1186/s13195-019-0505-0) contains supplementary material, which is available to authorized users.

Longitudinal study of hearing loss and subjective cognitive function decline in men

INTRODUCTION

We examined the relation between self-reported hearing loss, hearing aid use, and risk of subjective cognitive function (SCF) decline.

METHODS

We conducted an 8-year (2008-2016) longitudinal study of 10,107 men aged ≥62 years who reported their hearing status in 2006 and had no subjective cognitive concerns in 2008. Change in SCF scores was assessed by a 6-item questionnaire, and subjective decline was defined as new report of at least one SCF concern during follow-up.

RESULTS

Hearing loss was associated with higher risk of SCF decline. Compared with no hearing loss, the multivariable-adjusted relative risk (95% CI) of incident SCF decline was 1.30 (1.18, 1.42), 1.42 (1.26, 1.61), and 1.54 (1.22, 1.96) among men with mild, moderate, and severe hearing loss (no hearing aids), respectively (P-trend < .001). Among men with severe hearing loss who used hearing aids, the multivariable-adjusted relative risk (95% CI) was 1.37 (1.18, 1.60).

DISCUSSION

Hearing loss was associated with substantially higher risk of subsequent subjective cognitive decline in men.

Long-term intake of vegetables and fruits and subjective cognitive function in US men

OBJECTIVE

To evaluate the prospective association of long-term intake of vegetables and fruits with late-life subjective cognitive function (SCF).

METHODS

Among 27,842 men with a mean age of 51 years in 1986, we used multinomial logistic regression to examine the relation of vegetable and fruit consumption to future SCF. Average dietary intake was calculated from 5 repeated food frequency questionnaires collected every 4 years until 2002. SCF score was assessed twice (2008 and 2012) using a 6-item questionnaire; validity was supported by strong associations with APO ε4 genotype. We categorized the average of the 2 scores as good, moderate, and poor SCF.

RESULTS

Higher intakes of total vegetables, total fruits, and fruit juice were each significantly associated with lower odds of moderate or poor SCF after controlling for major nondietary factors and total energy intake. The association with total fruit intake was weaker after further adjusting for major dietary factors. In this model, the multivariate odds ratios (95% confidence intervals) for vegetable intake (top vs bottom quintile) were 0.83 (0.76-0.92), p trend <0.001 for moderate SCF and 0.66 (0.55-0.80), p trend <0.001 for poor SCF. For orange juice, compared to <1 serving/mo of intake, daily consumption was associated with a substantially lower odds of poor SCF (0.53 [0.43-0.67], p trend <0.001). Higher consumption of vegetables and fruits 18 to 22 years before SCF assessment was associated with lower odds of poor SCF independent of more proximal intake.

CONCLUSION

Our findings support a long-term beneficial role of vegetable, fruit, and orange juice consumption on SCF.

Associations between Prospective and Retrospective Subjective Memory Complaints and Neuropsychological Performance in Older Adults: The Finger Study

OBJECTIVES

Subjective memory complaints (SMCs) are among the key concerns in the elderly, but their role in detecting objective cognitive problems is unclear. The aim of this study was to clarify the association between SMCs (both prospective and retrospective memory complaints) and neuropsychological test performance in older adults at risk of cognitive decline.

METHODS

This investigation is part of the FINGER project, a multicenter randomized controlled trial aiming at preventing cognitive decline in high-risk individuals. The cognitive assessment of participants was conducted at baseline using a modified neuropsychological test battery (NTB). SMCs were evaluated with the Prospective and Retrospective Memory Questionnaire (PRMQ) in a sub-sample of 560 participants (mean age, 69.9 years).

RESULTS

Having more prospective SMCs was associated with slower processing speed, but not with other NTB domains. Retrospective SMCs were linked to poorer function on NTB total score, processing speed, and memory. Executive function domain was not associated with any PRMQ ratings. Depressive symptoms and poor quality of life diluted the observed associations for NTB total score and memory. However, the association between PRMQ and processing speed remained even after full adjustments.

CONCLUSIONS

Our results indicate that self-reported memory problems, measured with PRMQ, are associated with objectively measured cognitive performance. Such complaints in healthy elderly people also seem to reflect reduced mental tempo, rather than memory deficits. Slowing of processing speed may thus be negatively related to memory self-efficacy. It is also important to consider affective factors among those who report memory problems. (JINS, 2018, 24, 1099-1109).

Measuring cognition and function in the preclinical stage of Alzheimer's disease

The Alzheimer's Association's Research Roundtable met in November 2016 to explore how best to measure changes in cognition and function in the preclinical stage of Alzheimer's disease. This review will cover the tools and instruments currently available to identify populations for prevention trials, and measure subtle disease progression in the earliest stages of Alzheimer's disease, and will include discussions of suitable cognitive, behavioral, functional, composite, and biological endpoints for prevention trials. Current prevention trials are reviewed including TOMMOROW, Alzheimer's Prevention Initiative Autosomal Dominant Alzheimer's Disease Trial, the Alzheimer's Prevention Initiative Generation Study, and the Anti-Amyloid Treatment in Asymptomatic Alzheimer's to compare current approaches and tools that are being developed.

Subjective memory complaint as a useful tool for the early detection of Alzheimer's disease

PURPOSE

Despite their high prevalence in Alzheimer's disease (AD), and the increasing level of concern they have generated, subjective memory complaints (SMCs) are poorly understood. This study investigated the accuracy with which SMC can separate mild cognitive impairment (MCI) and early AD from cognitive normal (CN), and explored whether the discrimination ability is similar to or better than that of the Mini-Mental State Exam (MMSE).

PATIENTS AND METHODS

This study recruited 175 CN subjects, 52 with MCI, and 66 with probable AD aged 60 years or older. To test the independent contributions of SMC and MMSE scores to the classification of cognitive status (CN vs MCI or early AD), logistic regression analyses were performed, adjusting for the following potential confounding variables: age, gender, Frontal Assessment Battery score, modified Hachinski Ischemic Scale score, and apolipoprotein E ε4 status. Receiver operating characteristic (ROC) curve analyses were used to determine the discrimination accuracy of SMC and MMSE scores, and area under the ROC curve (AUROC) was also calculated.

RESULTS

In the highly educated (≥7 years), nondepressed (Geriatric Depression Scale ≤15) subgroup, SMC showed good accuracy in discriminating cognitively impaired subjects from CN after adjusting for potential confounding variables (the AUROC of the adjusted SMC was 0.841 for MCI discrimination, and it was 0.858 for MCI plus early AD discrimination). Both SMC and MMSE scores significantly contributed to differentiating between CN and MCI (OR=2.372, 95% CI=1.086-5.177; OR=0.730, 95% CI=0.566-0.941, respectively) after adjusting for the same covariates. However, in the highly educated and nondepressed subgroups, SMC showed significant predictive power for MCI from CN (OR=3.119, 95% CI=1.190-8.176; OR=3.328, 95% CI=1.320-8.396, respectively), whereas MMSE scores did not.

CONCLUSION

Our findings support the usefulness of SMC, which was comparable or even superior to MMSE scores, for detecting MCI or early AD.

Possible positive effect of the APOE ε2 allele on cognition in early to mid-adult life

BACKGROUND

ε4 allele possession is associated with an increased risk of Alzheimer's disease. Its effects earlier in life are less well understood. Previous studies have reported both detrimental effects and a lack of effect on cognition outside dementia. We used genotype based recall from the ALSPAC study to investigate whether APOE genotype influences cognition in earlier adult life.

METHODS

We invited all individuals with the rarer ε22 or ε44 genotypes and equal numbers of those with ε32, ε33 or ε34 APOE genotypes (total n invited = 1936, ages 23-67). Participants were screened for dementia using the Addenbrooke's Cognitive Examination Revised (ACE-R). Participants were asked to complete a 3 h battery of neuropsychological tests covering a range of cognitive domains. The primary outcome was performance on the Rey Auditory Verbal Learning Test (RAVLT). Transformation of variables was used where required to permit parametric testing. As genotypes are unlikely to be confounded unadjusted analyses were performed.

RESULTS

114 participants were recruited to the study (39 ε33, 27 ε34, 15 ε44, 26 ε32 & 7 ε22). ε4+ participants had higher scores on the cognitive failures questionnaire (10 point increase, p = 0.006) but no deficits on objective cognitive testing. ε2 carriers had slightly better episodic memory performance (p = 0.016), slightly improved n-back accuracy and better executive functioning (trails A&B, p = 0.005).

CONCLUSIONS

It is intriguing that the ε2+ group performed better as this group have a lower risk of Alzheimer's disease. Most previous studies have analysed as ε4/non ε4 so may have missed this effect.

Apolipoprotein E e4 Allele Is Associated with Subjective Cognitive Decline: A Meta-Analysis

BACKGROUND AND PURPOSE

Subjective cognitive decline (SCD) is a condition associated with increased risk of Alzheimer's disease. This study performs a meta-analysis to estimate the prevalence of the Apolipoprotein E e4 (APOE e4) allele in SCD and the association of APOE e4 with SCD.

METHODS

The MEDLINE, EMBASE, and Cochrane Library databases were searched. Meta-analyses were conducted using STATA 12.0 software. When significant heterogeneity was present (I2 >50% and p < 0.05), we conducted stratified and meta-regression analyses to explore possible reasons for heterogeneity.

RESULTS

We selected a total of 28 studies that were conducted in Australia, the United States, northern Europe, middle Europe, southern Europe, and Asia. The sample size of the SCD group was 6,044. Thirteen studies included a healthy control group (total control cohort of 3,822), whereas the remaining 15 studies were single-arm studies of SCD groups. The APOE e4 allele was associated with SCD (OR 1.12 [1.00-1.25]; p = 0.04). The pooled estimate for APOE e4 carrier prevalence was 32% (95% CI 28-35). Due to the significant heterogeneity in prevalence estimates, we performed stratified and meta-regression analyses and found that age and northern European residency were significantly associated with heterogeneity.

CONCLUSION

The results of this meta-analysis indicate a weak association between APOE e4 and SCD. Age and northern European residency are the critical factors that determine heterogeneity in the APOE e4-associated prevalence of SCD.

Adherence to Mediterranean diet and subjective cognitive function in men

Benefits of a Mediterranean diet for cognition have been suggested, but epidemiologic studies have been relatively small and of limited duration. To prospectively assess the association between long-term adherence to a Mediterranean dietary pattern and self-reported subjective cognitive function (SCF). Prospective observational study. The Health Professionals' Follow-up Study, a prospective cohort of 51,529 men, 40-75 years of age when enrolled in 1986, of whom 27,842 were included in the primary analysis. Mediterranean diet (MD) score, computed from the mean of five food frequency questionnaires, assessed every 4 years from 1986 to 2002. Self-reported SCF assessed by a 6-item questionnaire in 2008 and 2012, and validated by association with genetic variants in apolipoprotein-4. Using the average of 2008 and 2012 SCF scores, 38.0% of men were considered to have moderate memory scores and 7.3% were considered to have poor scores. In a multivariate model, compared with men having a MD score in the lowest quintile, those in the highest quintile had a 36% lower odds of a poor SCF score (odds ratio 0.64, 95% CI 0.55-0.75; P, trend < 0.001) and a 24% lower odds of a moderate SCF score (OR 0.76, 95% CI 0.70-0.83; P, trend < 0.001). Both remote and more recent diet contributed to this relation. Associations were only slightly weaker using baseline dietary data and a lag of 22 years. Long-term adherence to the Mediterranean diet pattern was strongly related to lower subjective cognitive function. These findings provide further evidence that a healthy dietary pattern may prevent or delay cognitive decline.

Subjective cognitive decline and β-amyloid burden predict cognitive change in healthy elderly

OBJECTIVE

To assess in a longitudinal study whether subjective cognitive decline (SCD) and brain β-amyloid (Aβ) contribute unique information to cognitive decline.

METHODS

One hundred thirty-six healthy elderly from the Berkeley Aging Cohort Study were followed up for a mean of 4 years. SCD and affective measures were generated from the Geriatric Depression Scale (GDS) with factor analysis on data from a larger set of 347 healthy, nondepressed (GDS <11) elderly individuals. Cognition was summarized with previously validated factor scores. Pittsburgh compound B (PiB)-PET scans were acquired to determine the presence (PiB+) or absence (PiB-) of Aβ pathology. Mixed models were used to assess the independent and interactive effects of SCD, affective features, PiB status, and time on cognition, with adjustment for demographic variables.

RESULTS

SCD score demonstrated good construct validity compared to an existing measure of subjective memory and was partially explained by several lower-order measurements. Mixed models revealed that SCD interacted with PiB status to predict change in episodic memory and global cognition over time, with adjustment for affective features. PiB+ individuals with more severe SCD demonstrated the steepest cognitive decline. Worse SCD predicted faster decline in working memory independently of PiB status. No such effects were seen for affective scores when adjusted for SCD.

CONCLUSIONS

PiB+ individuals with SCD are at greatest risk of cognitive decline. Evidence for amyloid alone is not sufficient to indicate risk of rapid cognitive decline in healthy elderly. Effects of GDS on cognitive decline in nondepressed cohorts may be driven by SCD rather than subsyndromal depression.

Longitudinal Assessment of Self- and Informant-Subjective Cognitive Complaints in a Sample of Healthy Late-Middle Aged Adults Enriched with a Family History of Alzheimer's Disease

OBJECTIVES

The purpose of this study was to investigate the longitudinal trajectory of self- and informant-subjective cognitive complaints (SCC), and to determine if SCC predict longitudinal changes in objective measures (OM) of cognitive function.

METHODS

The study included healthy and cognitively normal late middle-aged adults enriched with a family history of AD who were evaluated at up to three visits over a 4-year period. At each visit (Visit 1-3), self- and informant-SCC and OM were evaluated. Linear mixed models were used to determine if the longitudinal rate of change of self- and informant-SCC were associated with demographic variables, depressive symptoms, family history (FH), and apolipoprotein epsilon 4 (APOE4) status. The same modeling approach was used to examine the effect of Visit 1 SCC on longitudinal cognitive change after controlling for the same variables.

RESULTS

At Visit 1, more self-SCC were associated with fewer years of education and more depressive symptoms. SCC were also associated with poorer performance on cognitive measures, such that more self-SCC at Visit 1 were associated with poorer performance on memory and executive functioning measures at Visit 1, while more informant-SCC were associated with faster rate of longitudinal decline on a measure of episodic learning and memory. FH and APOE4 status were not associated with SCC.

DISCUSSION

Self- and informant-SCC showed an association with OM, albeit over different time frames in our late middle-aged sample. Additional longitudinal follow-up will likely assist in further clarifying these relationships as our sample ages and more pronounced cognitive changes eventually emerge. (JINS, 2017, 23, 617-626).

Adult height, dietary patterns, and healthy aging

Background: Adult height has shown directionally diverse associations with several age-related disorders, including cardiovascular disease, cancer, decline in cognitive function, and mortality.Objective: We investigated the associations of adult height with healthy aging measured by a full spectrum of health outcomes, including incidence of chronic diseases, memory, physical functioning, and mental health, among populations who have survived to older age, and whether lifestyle factors modified such relations.Design: We included 52,135 women (mean age: 44.2 y) from the Nurses' Health Study without chronic diseases in 1980 and whose health status was available in 2012. Healthy aging was defined as being free of 11 major chronic diseases and having no reported impairment of subjective memory, physical impairment, or mental health limitations.Results: Of all eligible study participants, 6877 (13.2%) were classified as healthy agers. After adjustment for demographic and lifestyle factors, we observed an 8% (95% CI: 6%, 11%) decrease in the odds of healthy aging per SD (0.062 m) increase in height. Compared with the lowest category of height (≤1.57 m), the OR of achieving healthy aging in the highest category (≥1.70 m) was 0.80 (95% CI: 0.73, 0.87; P-trend < 0.001). In addition, we found a significant interaction of height with a prudent dietary pattern in relation to healthy aging (P-interaction = 0.005), and among the individual dietary factors characterizing the prudent dietary pattern, fruit and vegetable intake showed the strongest effect modification (P-interaction = 0.01). The association of greater height with reduced odds of healthy aging appeared to be more evident among women with higher adherence to the prudent dietary pattern rich in vegetable and fruit intake.Conclusions: Greater height was associated with a modest decrease in the likelihood of healthy aging. A prudent diet rich in fruit and vegetables might modify the relation.

Objective features of subjective cognitive decline in a United States national database

INTRODUCTION

Functional and cognitive features of subjective cognitive decline (SCD) were identified in a longitudinal database from the National Alzheimer's Coordinating Center.

METHODS

Cognitively normal older adults with (SCD+) and without (SCD-) self-reported memory complaints (N = 3915) were compared on (1) baseline Functional Assessment Questionnaire ratings, (2) baseline scores and longitudinal rate of change estimates from nine neuropsychological tests, and (3) final clinical diagnoses.

RESULTS

SCD+ had higher baseline ratings of functional impairment, reduced episodic memory practice effects and poorer performance on neuropsychological tests of psychomotor speed and language, and higher frequencies of mild cognitive impairment and dementia diagnoses at the end of follow-up compared with the SCD-group.

DISCUSSION

Subtle clinical features of SCD identified in this large cohort are difficult to detect at the individual level. More sensitive tests are needed to identify those with SCD who are vulnerable to cognitive decline and dementia.

Cross-Sectional and Longitudinal Effects of CREB1 Genotypes on Individual Differences in Memory and Executive Function: Findings from the BLSA

Purpose: Previously, we have shown that the SNP rs10932201 genotype of the cyclic AMP responsive element binding protein 1 gene (CREB1) contributes to individual differences in executive and memory function at the neural system and behavioral levels in healthy, young adults. However, longitudinal effects of CREB1 genotypes on cognition have not yet been addressed. Furthermore we were interested in replicating associations between CREB1 genotypes and human cognition in previous cross-sectional studies and explore whether APOE𝜀4 status might modify these relations. Materials and Methods: We investigated whether common, independent tag SNPs within CREB1 (rs2253206, rs10932201, rs6785) influence individual differences in age-related longitudinal change and level of executive function and memory performance independent of baseline age, sex, APOE𝜀4 status, and education. Our analysis included data from cognitively unimpaired older adults participating in the Baltimore Longitudinal Study of Aging. Eleven measures from six cognitive tests (sample sizes range 617-786) were analyzed using linear mixed effects and generalized estimating equations models. Mean baseline age ranged from 50 to 69 years and mean time of follow-up (interval) ranged from 8 to 22 years. Results: We found significant effects of all three CREB1 SNPs on performance level and/or longitudinal change in performance based on eight measures assessing semantic memory, episodic memory, or both executive function and semantic memory. SNP rs10932201 showed the most significant and largest effect (Cohen's d = -0.70, p < 0.01) on age-related longitudinal decline of semantic memory. Additionally, we show interactions between all three CREB1 SNPs and APOE𝜀4 status on age-related longitudinal declines and levels of memory and executive function. Conclusion: Our results suggest that CREB1 genotypes independently and by interactions with APOE𝜀4 status contribute to individual differences in cognitive aging.