Trial of the MIND Diet for Prevention of Cognitive Decline in Older Persons.

BACKGROUND: Findings from observational studies suggest that dietary patterns may offer protective benefits against cognitive decline, but data from clinical trials are limited. The Mediterranean-DASH Intervention for Neurodegenerative Delay, known as the MIND diet, is a hybrid of the Mediterranean diet and the DASH (Dietary Approaches to Stop Hypertension) diet, with modifications to include foods that have been putatively associated with a decreased risk of dementia. METHODS: We performed a two-site, randomized, controlled trial involving older adults without cognitive impairment but with a family history of dementia, a body-mass index (the weight in kilograms divided by the square of the height in meters) greater than 25, and a suboptimal diet, as determined by means of a 14-item questionnaire, to test the cognitive effects of the MIND diet with mild caloric restriction as compared with a control diet with mild caloric restriction. We assigned the participants in a 1:1 ratio to follow the intervention or the control diet for 3 years. All the participants received counseling regarding adherence to their assigned diet plus support to promote weight loss. The primary end point was the change from baseline in a global cognition score and four cognitive domain scores, all of which were derived from a 12-test battery. The raw scores from each test were converted to z scores, which were averaged across all tests to create the global cognition score and across component tests to create the four domain scores; higher scores indicate better cognitive performance. The secondary outcome was the change from baseline in magnetic resonance imaging (MRI)-derived measures of brain characteristics in a nonrandom sample of participants. RESULTS: A total of 1929 persons underwent screening, and 604 were enrolled; 301 were assigned to the MIND-diet group and 303 to the control-diet group. The trial was completed by 93.4% of the participants. From baseline to year 3, improvements in global cognition scores were observed in both groups, with increases of 0.205 standardized units in the MIND-diet group and 0.170 standardized units in the control-diet group (mean difference, 0.035 standardized units; 95% confidence interval, -0.022 to 0.092; P = 0.23). Changes in white-matter hyperintensities, hippocampal volumes, and total gray- and white-matter volumes on MRI were similar in the two groups. CONCLUSIONS: Among cognitively unimpaired participants with a family history of dementia, changes in cognition and brain MRI outcomes from baseline to year 3 did not differ significantly between those who followed the MIND diet and those who followed the control diet with mild caloric restriction. (Funded by the National Institute on Aging; ClinicalTrials.gov number, NCT02817074.).

Post-traumatic stress disorder symptom remission and cognition in a large cohort of civilian women.

BACKGROUND: Post-traumatic stress disorder (PTSD) is associated with cognitive impairments. It is unclear whether problems persist after PTSD symptoms remit. METHODS: Data came from 12 270 trauma-exposed women in the Nurses' Health Study II. Trauma and PTSD symptoms were assessed using validated scales to determine PTSD status as of 2008 (trauma/no PTSD, remitted PTSD, unresolved PTSD) and symptom severity (lifetime and past-month). Starting in 2014, cognitive function was assessed using the Cogstate Brief Battery every 6 or 12 months for up to 24 months. PTSD associations with baseline cognition and longitudinal cognitive changes were estimated by covariate-adjusted linear regression and linear mixed-effects models, respectively. RESULTS: Compared to women with trauma/no PTSD, women with remitted PTSD symptoms had a similar cognitive function at baseline, while women with unresolved PTSD symptoms had worse psychomotor speed/attention and learning/working memory. In women with unresolved PTSD symptoms, past-month PTSD symptom severity was inversely associated with baseline cognition. Over follow-up, both women with remitted and unresolved PTSD symptoms in 2008, especially those with high levels of symptoms, had a faster decline in learning/working memory than women with trauma/no PTSD. In women with remitted PTSD symptoms, higher lifetime PTSD symptom severity was associated with a faster decline in learning/working memory. Results were robust to the adjustment for sociodemographic, biobehavioral, and health factors and were partially attenuated when adjusted for depression. CONCLUSION: Unresolved but not remitted PTSD was associated with worse cognitive function assessed six years later. Accelerated cognitive decline was observed among women with either unresolved or remitted PTSD symptoms.

Mitochondrial DNA variation in Alzheimer's disease reveals a unique microprotein called SHMOOSE.

Mitochondrial DNA variants have previously associated with disease, but the underlying mechanisms have been largely elusive. Here, we report that mitochondrial SNP rs2853499 associated with Alzheimer's disease (AD), neuroimaging, and transcriptomics. We mapped rs2853499 to a novel mitochondrial small open reading frame called SHMOOSE with microprotein encoding potential. Indeed, we detected two unique SHMOOSE-derived peptide fragments in mitochondria by using mass spectrometry-the first unique mass spectrometry-based detection of a mitochondrial-encoded microprotein to date. Furthermore, cerebrospinal fluid (CSF) SHMOOSE levels in humans correlated with age, CSF tau, and brain white matter volume. We followed up on these genetic and biochemical findings by carrying out a series of functional experiments. SHMOOSE acted on the brain following intracerebroventricular administration, differentiated mitochondrial gene expression in multiple models, localized to mitochondria, bound the inner mitochondrial membrane protein mitofilin, and boosted mitochondrial oxygen consumption. Altogether, SHMOOSE has vast implications for the fields of neurobiology, Alzheimer's disease, and microproteins.

Correlates of missed or late versus timely diagnosis of dementia in healthcare settings.

INTRODUCTION: There is limited evidence about factors related to the timeliness of dementia diagnosis in healthcare settings. METHODS: In five prospective cohorts at Rush Alzheimer's Disease Center, we identified participants with incident dementia based on annual assessments and examined the timing of healthcare diagnoses in Medicare claims. We assessed sociodemographic, health, and psychosocial correlates of timely diagnosis. RESULTS: Of 710 participants, 385 (or 54%) received a timely claims diagnosis within 3 years prior to or 1 year following dementia onset. In logistic regressions accounting for demographics, we found Black participants (odds ratio [OR] = 2.15, 95% confidence interval [CI]: 1.21 to 3.82) and those with better cognition at dementia onset (OR = 1.48, 95% CI: 1.10 to 1.98) were at higher odds of experiencing a diagnostic delay, whereas participants with higher income (OR = 0.89, 95% CI: 0.81 to 0.97) and more comorbidities (OR = 0.94, 95% CI: 0.89 to 0.98) had lower odds. DISCUSSION: We identified characteristics of individuals who may miss the optimal window for dementia treatment and support. HIGHLIGHTS: We compared the timing of healthcare diagnosis relative to the timing of incident dementia based on rigorous annual evaluation. Older Black adults with lower income, higher cognitive function, and fewer comorbidities were less likely to be diagnosed in a timely manner by the healthcare system.

Effect of Vitamin D Supplementation on Overactive Bladder and Urinary Incontinence Symptoms in Older Men: Ancillary Findings From a Randomized Trial.

PURPOSE: Our goal was to evaluate vitamin D supplementation for preventing or treating overactive bladder and urinary incontinence in men. MATERIALS AND METHODS: Ancillary study of men aged ≥55 years in VITAL (VITamin D and OmegA-3 TriaL). Randomized treatments included: vitamin D3 (cholecalciferol), marine omega-3 fatty acids, or matching placebo. Structured urinary incontinence questions measured the prevalence of overactive bladder at year 5 and urinary incontinence at years 2 and 5, along with incidence and progression of urinary incontinence from years 2 to 5. Prespecified subgroup analyses examined men with low baseline serum 25-hydroxyvitamin D (<20 ng/mL). RESULTS: Among the 11,486 men who provided data at year 2 and 10,474 at year 5, mean age was 68 years at year 2, with 23% racial/ethnic minorities. In primary analyses, vitamin D supplementation compared to placebo did not lower odds of overactive bladder at year 5 (OR 0.97, 95% CI 0.87-1.08) or weekly urinary incontinence at year 2 (OR 0.94, 95% CI 0.83-1.05) or year 5 (OR 0.98, 95% CI 0.88-1.09). We found interactions of baseline serum 25-hydroxyvitamin D level with vitamin D supplementation for overactive bladder (P value for interaction = .001), and secondarily, for any urinary incontinence at year 2 (P value for interaction = .05). Men with baseline 25-hydroxyvitamin D <20 ng/mL, who were assigned to vitamin D supplements, had lower odds of overactive bladder (OR 0.51, 95% CI 0.35-0.76) compared to placebo, yet higher odds of any urinary incontinence (OR 1.24, 95% CI 0.93-1.64). CONCLUSIONS: Overall, vitamin D supplementation did not improve overactive bladder or urinary incontinence compared to placebo. However, specific use of vitamin D in men with lower 25-hydroxyvitamin D levels had inconsistent findings.

Epigenome-Wide Analysis of DNA Methylation and Optimism in Women and Men.

OBJECTIVE: Higher optimism is associated with reduced mortality and a lower risk of age-related chronic diseases. DNA methylation (DNAm) may provide insight into mechanisms underlying these relationships. We hypothesized that DNAm would differ among older individuals who are more versus less optimistic. METHODS: Using cross-sectional data from two population-based cohorts of women with diverse races/ethnicities ( n = 3816) and men (only White, n = 667), we investigated the associations of optimism with epigenome-wide leukocyte DNAm. Random-effects meta-analyses were subsequently used to pool the individual results. Significantly differentially methylated cytosine-phosphate-guanines (CpGs) were identified by the "number of independent degrees of freedom" approach: effective degrees of freedom correction using the number of principal components (PCs), explaining >95% of the variation of the DNAm data (PC-correction). We performed regional analyses using comb-p and pathway analyses using the Ingenuity Pathway Analysis software. RESULTS: We found that essentially all CpGs (total probe N = 359,862) were homogeneous across sex and race/ethnicity in the DNAm-optimism association. In the single CpG site analyses based on homogeneous CpGs, we identified 13 significantly differentially methylated probes using PC-correction. We found four significantly differentially methylated regions and two significantly differentially methylated pathways. The annotated genes from the single CpG site and regional analyses are involved in psychiatric disorders, cardiovascular disease, cognitive impairment, and cancer. Identified pathways were related to cancer, and neurodevelopmental and neurodegenerative disorders. CONCLUSION: Our findings provide new insights into possible mechanisms underlying optimism and health.

Long-Term Consumption of Nuts (Including Peanuts, Peanut Butter, Walnuts, and Other Nuts) in Relation to Risk of Frailty in Older Women: Evidence from a Cohort Study.

BACKGROUND: Adherence to a healthy diet is inversely associated with frailty. However, the relationship between nuts, a key food group of Mediterranean diet, and frailty is unclear. OBJECTIVES: This study aimed to evaluate the association between nut consumption and frailty in an aging female population. METHODS: This population-based observational study included nonfrail women (≥60 y old) in the NHS from 11 states of the United States. Outcome was incident frailty, defined as having ≥3 of the FRAIL components (fatigue, lower strength, reduced aerobic capacity, multiple chronic conditions, and significant weight loss) and assessed every 4 y from 1992 to 2016. From 1990 to 2014, FFQs were used to assess the intakes of peanuts, peanut butter, walnuts (added in 1998), and other nuts at 4-y intervals. Exposure was total nut consumption, calculated as the sum of intakes of peanuts, peanut butter, walnuts, and other nuts and categorized into <1 serving/mo, 1-3 servings/mo, 1 serving/wk, 2-4 servings/wk, and ≥5 servings/wk. The relations of intakes of peanuts, peanut butter, and walnuts with frailty were also investigated separately. Cox proportional hazards models were used to assess the associations between nut consumption and frailty after adjusting for age, smoking, BMI, EI, diet quality, and medication use. RESULTS: Among 71,704 participants, 14,195 incident frailty cases occurred over 1,165,290 person-years. The adjusted HR (95% CI) for consuming ≥5 servings/wk of nuts was 0.80 (0.73, 0.87), as compared with <1 serving/mo. Higher intakes of peanuts and walnuts, but not peanut butter, were also inversely associated with frailty. CONCLUSIONS: This large prospective cohort study showed a strong and consistent inverse association between regular nut consumption and incident frailty. This suggests that nut consumption should be further tested as a convenient public health intervention for the preservation of health and well-being in older adults.

Genome-wide meta-analyses reveal novel loci for verbal short-term memory and learning.

Understanding the genomic basis of memory processes may help in combating neurodegenerative disorders. Hence, we examined the associations of common genetic variants with verbal short-term memory and verbal learning in adults without dementia or stroke (N = 53,637). We identified novel loci in the intronic region of CDH18, and at 13q21 and 3p21.1, as well as an expected signal in the APOE/APOC1/TOMM40 region. These results replicated in an independent sample. Functional and bioinformatic analyses supported many of these loci and further implicated POC1. We showed that polygenic score for verbal learning associated with brain activation in right parieto-occipital region during working memory task. Finally, we showed genetic correlations of these memory traits with several neurocognitive and health outcomes. Our findings suggest a role of several genomic loci in verbal memory processes.

Associations between circulating cell-free mitochondrial DNA, inflammatory markers, and cognitive and physical outcomes in community dwelling older adults.

BACKGROUND: Dementia and frailty are common age-related syndromes often linked to chronic inflammation. Identifying the biological factors and pathways that contribute to chronic inflammation is crucial for developing new therapeutic targets. Circulating cell-free mitochondrial DNA (ccf-mtDNA) has been proposed as an immune stimulator and potential predictor of mortality in acute illnesses. Dementia and frailty are both associated with mitochondrial dysfunction, impaired cellular energetics, and cell death. The size and abundance of ccf-mtDNA fragments may indicate the mechanism of cell death: long fragments typically result from necrosis, while short fragments arise from apoptosis. We hypothesize that increased levels of necrosis-associated long ccf-mtDNA fragments and inflammatory markers in serum are linked to declines in cognitive and physical function, as well as increased mortality risk. RESULTS: Our study of 672 community-dwelling older adults revealed that inflammatory markers (C-Reactive Protein, soluble tumor necrosis factor alpha, tumor necrosis factor alpha receptor 1 [sTNFR1], and interleukin-6 [IL-6]) positively correlated with ccf-mtDNA levels in serum. Although cross-sectional analysis revealed no significant associations between short and long ccf-mtDNA fragments, longitudinal analysis demonstrated a connection between higher long ccf-mtDNA fragments (necrosis-associated) and worsening composite gait scores over time. Additionally, increased mortality risk was observed only in individuals with elevated sTNFR1 levels. CONCLUSION: In a community dwelling cohort of older adults, there are cross-sectional and longitudinal associations between ccf-mtDNA and sTNFR1 with impaired physical and cognitive function and increased hazard of death. This work suggests a role for long ccf-mtDNA as a blood-based marker predictive of future physical decline.

Social integration and risk of mortality among African-Americans: the Jackson heart study.

OBJECTIVE: Evidence suggests that greater social integration is related to lower mortality rates. However, studies among African-Americans are limited. We examined whether higher social integration was associated with lower mortality in 5306 African-Americans from the Jackson Heart Study, who completed the Berkman-Syme Social Network Index in 2000-2004 and were followed until 2018. METHODS: We estimated hazard ratios (HR) of mortality by categories of the Social Network Index (i.e., high social isolation, moderate social isolation [reference group], moderate social integration, high social integration) using Cox proportional hazard models. Covariates included baseline sociodemographics, depressive symptoms, health conditions, and health behaviors. RESULTS: Compared with moderate isolation, moderate integration was associated with an 11% lower mortality rate (HR = 0.89, 95% confidence interval [CI] 0.77, 1.03), and high integration was associated with a 25% lower mortality rate (HR = 0.75, 95% CI 0.64, 0.87), controlling for sociodemographics and depressive symptoms; compared with moderate isolation, high isolation was related to a 34% higher mortality rate (HR = 1.34, 95% CI 1.00, 1.79). Further adjustment of potential mediators (health conditions and health behaviors) only slightly attenuated HRs (e.g., HRmoderate integration = 0.90, 95% CI 0.78, 1.05; HRhigh integration = 0.77, 95% CI 0.66, 0.89). CONCLUSION: Social integration may be a psychosocial health asset with future work needed to identify biobehavioral processes underlying observed associations with mortality among African-Americans.

The association of MIND diet with cognitive resilience to neuropathologies.

INTRODUCTION: Cognitive resilience (CR) can be defined as the continuum of better through worse than expected cognition, given the degree of neuropathology. The relation of healthy diet patterns to CR remains to be elucidated. METHODS: Using longitudinal cognitive data and post mortem neuropathology from 578 deceased older adults, we examined associations between the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet at baseline and two standardized CR measures reflecting higher cognitive levels over time (CR Level ¯ $_{\overline {{\rm{Level}}}} $ ), and slower decline (CRSlope ), than expected given neuropathology. RESULTS: Compared to individuals in the lowest tertile of MIND score, those in the top tertile had higher CR Level ¯ $_{\overline {{\rm{Level}}}} $ (mean difference [MD] = 0.34; 95% confidence interval [CI] = 0.14, 0.55) and CRSlope (MD = 0.27; 95% CI = 0.05, 0.48), after multivariable adjustment. Overall MIND score was more strongly related to CR than the individual food components. DISCUSSION: The MIND diet is associated with both higher cognition and slower rates of cognitive decline, after controlling for neuropathology, indicating the MIND diet may be important to cognitive resilience.

Empirical Dietary Inflammatory Pattern Scores Are Not Associated with Worse Cognitive Performance in the Nurses' Health Study.

BACKGROUND: Low-grade chronic inflammation associated with unhealthy diets may lead to cognitive aging. OBJECTIVES: We evaluated whether higher long-term adherence to an empirical dietary inflammatory pattern (EDIP) was associated with lower cognitive function after age 70 y in the Nurses' Health Study. METHODS: A total of 16,058 older (mean ± SD age: 74 ± 2 y) highly educated (≥ bachelor degree) White women completed up to 5 validated 116-item food-frequency questionnaires. An EDIP score, previously derived with the use of reduced rank regression to predict circulating inflammatory markers (i.e., C-reactive protein, TNF-α receptor 2, and IL-6), was computed based on 9 anti-inflammatory and 9 proinflammatory components. A long-term EDIP score was calculated by averaging across 5 exams. The EDIP score was categorized into quintiles, taking the first (anti-inflammatory) quintile as the reference category. Cognitive testing was performed through telephone interviews over 4 follow-up exams (1995-2008). A composite global cognition score, a composite verbal memory score, and the Telephone Interview for Cognitive Status (TICS) were calculated and averaged across the 4 exams (6 y of follow-up). Multivariable linear regressions were used to examine longitudinal relations under study. RESULTS: Higher long-term EDIP scores (i.e., more proinflammatory) were significantly associated with worse performance on global cognitive function (P-trend= 0.018) and TICS (P-trend= 0.004) after adjustment for demographic and lifestyle factors. The associations became nonsignificant after additional adjustments for disease (related) risk factors for dementia. No association was observed between the EDIP score and verbal memory. CONCLUSIONS: We observed no relation between long-term EDIP scores and averaged global cognitive function and verbal memory among older women. Our findings suggest no relation between long-term adherence to a proinflammatory diet and cognitive function in a large population of mostly White and generally highly educated older women. Future studies are encouraged to investigate the relation between inflammatory diets and cognitive function in other races/ethnicities and men, and over a longer follow-up period.

Effect of vitamin D supplementation on urinary incontinence in older women: ancillary findings from a randomized trial.

BACKGROUND: Observational studies among older women have associated vitamin D insufficiency with a greater prevalence and incidence of urinary incontinence. However, little is known about the effect of vitamin D supplementation in reducing urinary incontinence. OBJECTIVE: This study aimed to evaluate the effects of vitamin D supplementation in reducing the frequency of urinary incontinence in older women. STUDY DESIGN: We conducted an ancillary study of women aged ≥55 years in the Vitamin D and Omega-3 Trial, a randomized trial with a 2×2 factorial design. Recruitment of participants started from 2011 to 2014 across 50 US states, and the follow-up of participants ended in January 2018. Randomized treatments in the parent study included (1) vitamin D3 (cholecalciferol) at a dosage of 2000 IU/d, (2) marine omega-3 fatty acids at a dosage of 1 g/d, and (3) matching placebo. Here, we analyzed women according to their randomization to vitamin D supplementation or placebo, regardless of treatment with omega-3 fatty acid supplementation. Validated frequency of urinary incontinence questions were added in year 2 of the study and were used again in year 5 at the end of trial. Prespecified ancillary outcomes included the prevalence of urinary incontinence at years 2 and 5, along with incident incontinence and progression of incontinence (from lower to higher frequency) from year 2 to year 5. Preplanned subgroup analyses examined the following outcomes: prerandomization of low serum levels of vitamin D (serum 25-hydroxyvitamin D<20 ng/mL), incontinence types, weight categories, and African American race. RESULTS: Among the randomized women who provided urinary incontinence data, 11,646 women at year 2 and 10,527 women at year 5, the mean age was 70 years at year 2, with 29% racial and ethnic minorities. The prevalence of urinary incontinence that occurred at least weekly was 29% at year 2 and increased to 37% at year 5. Vitamin D supplementation compared to with placebo was not associated with lower odds of urinary incontinence occurring at least weekly at year 2 (odds ratio, 1.08; 95% confidence interval, 0.99-1.19) or year 5 (odds ratio, 1.04; 95% confidence interval, 0.94-1.15). Vitamin D supplementation compared to placebo was not associated with lower incidence or progression of urinary incontinence from year 2 to year 5: incidence (odds ratio, 1.06; 95% confidence interval, 0.83-1.35) or progression (odds ratio, 0.94; 95% confidence interval, 0.82-1.08). Women with prerandomization of low serum levels of vitamin D (n=836) did not have lower odds of the prevalence, incidence, or progression of urinary incontinence. The findings were null in subgroups according to incontinence type, women with obesity, and African American women. Only women with healthy weight randomized to vitamin D had lower odds of progression of urinary incontinence (odds ratio, 0.78; 95% confidence interval, 0.63-0.95; P=.01). CONCLUSION: Vitamin D supplementation compared to placebo for 2 to 5 years was not associated with differences in the prevalence, incidence, or progression of urinary incontinence in older women with and without adequate serum vitamin D levels, with inconsistent differences among subgroups. The findings showed that the broad use of moderate doses of vitamin D supplementation did not reduce urinary incontinence in older women.

Optimism and risk of mortality among African-Americans: The Jackson heart study.

Optimism is associated with reduced mortality risk among Whites, but evidence for this relationship is limited among African-Americans, whose life expectancy is shorter than Whites. This study examined the association between optimism and mortality rate in African-Americans. Data were from African-American women (n = 2652) and men (n = 1444) in the United States from the Jackson Heart Study. Optimism was measured using the Life Orientation Test-Revised at the baseline period (2000-2004), and mortality data were obtained until 2018. Using Cox proportional hazards models, we estimated hazard ratios (HRs) of mortality by optimism level, controlling for sociodemographic factors, depressive symptoms, health conditions, and health behaviors. In secondary analyses, we evaluated potential effect modification by sex, age, income, and education. Higher optimism was related to lower mortality rates (HR = 0.85, 95% confidence interval [CI] = 0.74, 0.99), controlling for sociodemographic factors and depressive symptoms. After further adjusting for health conditions and health behaviors, associations were slightly attenuated (HR = 0.89; 95%CI = 0.77, 1.02). Stronger associations between optimism and mortality were observed in men, among those with higher income or education, and with age ≤ 55 (all p's for interaction terms <0.06). In summary, optimism was associated with lower mortality rates among African-Americans in the Jackson Heart Study. Effect modification by sociodemographic factors should be further explored in additional research considering optimism and mortality in diverse populations. Positive factors, such as optimism, may provide important health assets that can complement ongoing public health efforts to reduce health disparities, which have traditionally focused primarily on risk factors.

The association of posttraumatic stress disorder, depression, and head injury with mid-life cognitive function in civilian women.

BACKGROUND: Despite evidence linking posttraumatic stress disorder (PTSD), depression, and head injury, separately, with worse cognitive performance, investigations of their combined effects on cognition are limited in civilian women. METHODS: The Cogstate Brief Battery assessment was administered in 10,681 women from the Nurses' Health Study II cohort, mean age 64.9 years (SD = 4.6). Psychological trauma, PTSD, depression, and head injury were assessed using online questionnaires. In this cross-sectional analysis, we used linear regression models to estimate mean differences in cognition by PTSD/depression status and stratified by history of head injury. RESULTS: History of head injury was prevalent (36%), and significantly more prevalent among women with PTSD and depression (57% of women with PTSD and depression, 21% of women with no psychological trauma or depression). Compared to having no psychological trauma or depression, having combined PTSD and depression was associated with worse performance on psychomotor speed/attention ( ß = -.15, p = .001) and learning/working memory ( ß = -.15, p < .001). The joint association of PTSD and depression on worse cognitive function was strongest among women with past head injury, particularly among those with multiple head injuries. CONCLUSIONS: Head injury, like PTSD and depression, was highly prevalent in this sample of civilian women. In combination, these factors were associated with poorer performance on cognitive tasks, a possible marker of future cognitive health. Head injury should be further explored in future studies of PTSD, depression and cognition in women.

APOE ε4 and late-life cognition: mediation by structural brain imaging markers.

The apolipoprotein E allele 4 (APOE-ε4) is established as a major genetic risk factor for cognitive decline and late-onset Alzheimer's disease. Accumulating evidence has linked ε4 carriership to abnormal structural brain changes across the adult lifespan. To better understand the underlying causal mechanisms, we investigated the extent to which the effect of the ε4 allele on cognition is mediated by structural brain imaging markers in the population-based Age, Gene/Environment Susceptibility-Reykjavik Study (AGES-Reykjavik). This study included 4527 participants (aged 76.3 ± 5.4 at baseline) who underwent the brain magnetic resonance imaging assessment (of brain tissue volumes, white matter lesion volume, subcortical and cortical infarcts, and cerebral microbleeds) and a battery of neuropsychological tests at baseline. Causal mediation analysis was used to quantify the mediation of the ε4 effect on cognition by these MRI markers, both individually and jointly. We observed that about 9% of the total effect of ε4 carriership on cognition was mediated by white matter lesion volume. This proportion increased to 25% when total brain tissue volume was jointly considered with white matter lesion volume. In analyses separating ε4 homozygotes from ε4 heterozygotes, the effect on global cognition of specifically ε4 homozygosity appeared to be partially mediated by cerebral microbleeds, particularly lobar microbleeds. There was no evidence of mediation of the ε4 effect by cortical or subcortical infarcts. This study shows that the ε4 effect on cognition is partly mediated by white matter lesion volume and total brain tissue volume. These findings suggest the joint role of cerebral small vessel disease and neurodegeneration in the ε4-cognition relationship.

Patterns of lifestyle behaviours from mid- through later-life in relation to exceptional episodic memory performance in older women: the Nurses' Health Study.

OBJECTIVES: to model and compare patterns from mid- to late-life of body mass index (BMI), alternate Mediterranean diet (A-MeDi) and physical activity, between women with exceptional episodic memory over age 80 and cognitively average controls. Our goal was to examine if lifestyle risk factors in early adulthood may be identified which promote exceptional memory status later in life. METHODS: a case-control sample nested within the Nurses' Health Study (initiated in 1976), including 7,557 cognitively healthy participants who survived to age 80 and had a cognitive assessment at 80-87 years. We defined women with exceptional memory (n = 455) as those with a composite score of episodic memory ≥1.5 standard deviation above the mean. Then, we selected 2,275 cognitively average controls with a score within 1 standard deviation of the mean, matched by age and education. Patterns of BMI, A-MeDi and physical activity at 52-62 through age 82 years were estimated between groups using latent process mixed models. RESULTS: In midlife, women with exceptional episodic memory had similar BMI (mean difference [MD] = -0.07 kg/m2 [95% confidence intervals {CI}:-0.41; 0.26]) but better adherence to A-MeDi (MD = +0.25 points [0.08; 0.43]) and more physical activity (MD = +3.50 metabolic-equivalent h/week [1.97; 5.09]) than controls. However, with ageing, both groups had similar patterns; both initially gained and later lost weight, had less activity and declining diet quality (all group-by-time interactions P > 0.07). CONCLUSIONS: our findings suggest that lifestyle factors differ primarily at earlier ages for those with exceptional versus average episodic memory, thus lifestyle may be most important in earlier life to preserve high levels of memory.

Optimism is associated with exceptional longevity in 2 epidemiologic cohorts of men and women.

Most research on exceptional longevity has investigated biomedical factors associated with survival, but recent work suggests nonbiological factors are also important. Thus, we tested whether higher optimism was associated with longer life span and greater likelihood of exceptional longevity. Data are from 2 cohorts, women from the Nurses' Health Study (NHS) and men from the Veterans Affairs Normative Aging Study (NAS), with follow-up of 10 y (2004 to 2014) and 30 y (1986 to 2016), respectively. Optimism was assessed using the Life Orientation Test-Revised in NHS and the Revised Optimism-Pessimism Scale from the Minnesota Multiphasic Personality Inventory-2 in NAS. Exceptional longevity was defined as survival to age 85 or older. Primary analyses used accelerated failure time models to assess differences in life span associated with optimism; models adjusted for demographic confounders and health conditions, and subsequently considered the role of health behaviors. Further analyses used logistic regression to evaluate the likelihood of exceptional longevity. In both sexes, we found a dose-dependent association of higher optimism levels at baseline with increased longevity (P trend < 0.01). For example, adjusting for demographics and health conditions, women in the highest versus lowest optimism quartile had 14.9% (95% confidence interval, 11.9 to 18.0) longer life span. Findings were similar in men. Participants with highest versus lowest optimism levels had 1.5 (women) and 1.7 (men) greater odds of surviving to age 85; these relationships were maintained after adjusting for health behaviors. Given work indicating optimism is modifiable, these findings suggest optimism may provide a valuable target to test for strategies to promote longevity.

Quantifying longitudinal cognitive resilience to Alzheimer's disease and other neuropathologies.

INTRODUCTION: Cognitive resilience (CR) has been defined as the continuum of better (or worse) than expected cognition, given the degree of neuropathology. To quantify this concept, existing approaches focus on either cognitive level at a single time point or slopes of cognitive decline. METHODS: In a prospective study of 1215 participants, we created a continuous measure of CR defined as the mean of differences between estimated person-specific and marginal cognitive levels over time, after accounting for neuropathologies. RESULTS: Neuroticism and depressive symptoms were associated with all CR measures (P-values < .012); as expected, cognitive activity and education were only associated with the cognitive-level approaches (P-values < .0002). However, compared with the existing CR measures focusing on a single measure or slopes of cognition, our new measure yielded stronger relations with risk factors. DISCUSSION: Defining CR based on the longitudinal differences between person-specific and marginal cognitive levels is a novel and complementary way to quantify CR.

The association of epigenetic clocks in brain tissue with brain pathologies and common aging phenotypes.

Epigenetic clocks are calculated by combining DNA methylation states across select CpG sites to estimate biologic age, and have been noted as the most successful markers of biologic aging to date. Yet, limited research has considered epigenetic clocks calculated in brain tissue. We used DNA methylation states in dorsolateral prefrontal cortex specimens from 721 older participants of the Religious Orders Study and Rush Memory and Aging Project, to calculate DNA methylation age using four established epigenetic clocks: Hannum, Horvath, PhenoAge, GrimAge, and a new Cortical clock. The four established clocks were trained in blood samples (Hannum, PhenoAge, GrimAge) or using 51 human tissue and cell types (Horvath); the recent Cortical clock is the first trained in postmortem cortical tissue. Participants were recruited beginning in 1994 (Religious Orders Study) and 1997 (Memory and Aging Project), and followed annually with questionnaires and clinical evaluations; brain specimens were obtained for 80-90% of participants. Mean age at death was 88.0 (SD 6.7) years. We used linear regression, logistic regression, and linear mixed models, to examine relations of epigenetic clock ages to neuropathologic and clinical aging phenotypes, controlling for chronologic age, sex, education, and depressive symptomatology. Hannum, Horvath, PhenoAge and Cortical clock ages were related to pathologic diagnosis of Alzheimer's disease (AD), as well as to Aß load (a hallmark pathology of Alzheimer's disease). However, associations were substantially stronger for the Cortical than other clocks; for example, each standard deviation (SD) increase in Hannum, Horvath, and PhenoAge clock age was related to approximately 30% greater likelihood of pathologic AD (all p < 0.05), while each SD increase in Cortical age was related to 90% greater likelihood of pathologic AD (odds ratio = 1.91, 95% confidence interval 1.38, 2.62). Moreover, Cortical age was significantly related to other AD pathology (eg, mean tau tangle density, p = 0.003), and to odds of neocortical Lewy body pathology (for each SD increase in Cortical age, odds ratio = 2.00, 95% confidence 1.27, 3.17), although no clocks were related to cerebrovascular neuropathology. Cortical age was the only epigenetic clock significantly associated with the clinical phenotypes examined, from dementia to cognitive decline (5 specific cognitive systems, and a global cognitive measure averaging 17 tasks) to Parkinsonian signs. Overall, our findings provide evidence of the critical necessity for bespoke clocks of brain aging for advancing research to understand, and eventually prevent, neurodegenerative diseases of aging.