Examining a Healthy Lifestyle as a Moderator of the Relationship between Psychological Distress and Cognitive Decline among Older Adults in the NuAge Study.

INTRODUCTION: The objective of this study was to examine whether a healthy lifestyle composite score of social engagement, physical activity, and Mediterranean diet adherence moderates the association between psychological distress and global cognitive decline among cognitively healthy older adults (67+ years of age at baseline). METHODS: A total of 1,272 cognitively intact older adults (Mage = 74.1 ± 4.1 years, 51.9% female) in the Quebec Longitudinal Study on Nutrition and Successful Aging (NuAge) completed a series of self-reported questionnaires to measure psychological distress and lifestyle behaviors, and the Modified Mini-Mental Examination (3MS) to assess cognitive performance at baseline and annually over 3 years. RESULTS: Controlling for sociodemographic and health-related characteristics, greater psychological distress was associated with steeper cognitive decline over time among males (B = -0.07, 95% CI: [-0.12, -0.02]), but not females (B = 0.008, 95% CI: [0.03, 0.04]). Although a healthy lifestyle composite score did not statistically significantly moderate the distress-cognition relationship (B = -0.005, 95% CI: [-0.02, 0.01]), there was an association between higher psychological distress and greater cognitive decline at low levels of social engagement (B = -0.05, 95% CI: [-0.09, -0.006]), but not at high levels of social engagement (B = 0.02, 95% CI: [-0.03, 0.07]). CONCLUSION: This study suggests that the potentially harmful impact of stress on cognitive function may be malleable through specific healthy lifestyle behaviors and emphasizes the importance of taking a sex-based approach to cognitive aging research.

Psychological Stress across the Lifespan and Cognitive Function among Older Adults: The Moderating Role of a Healthy Lifestyle.

This study aimed to (a) investigate the associations between indices of stress severity across the lifespan (early, middle, late life) and cognitive function among community-dwelling older adults, and (b) examine whether a healthy lifestyle composite score comprised of physical activity, healthy diet adherence, social engagement, sleep quality, and mindful relaxation moderates the associations between lifespan stress severity and cognitive function. Participants (n = 226, Mage = 68.2 ± 6.5, 68.1% female) completed questionnaires to measure stress and lifestyle behaviours, and three online neurocognitive tasks. No direct associations between stress severity and cognition were found. The healthy lifestyle composite score moderated the associations between early, midlife, and late-life stress severity and inhibitory control. Exploratory analyses suggest that this moderating effect may be sex-dependent. Despite study limitations and the need for additional research, findings provide preliminary support for the role of lifestyle behaviours in enhancing older adults' resilience to the effects of stress on cognitive health in a sex-specific manner.

Cumulative Stress Exposure and Cognitive Function Among Older Adults: The Moderating Role of a Healthy Lifestyle.

OBJECTIVES: Although chronic stress is a risk factor for poor age-related cognitive health, there is limited research that has examined how cumulative stress across the lifespan affects cognitive aging. There may also be resilience factors that minimize the effects of cumulative stress on cognitive health. Engaging in a healthy lifestyle is protective against cognitive decline and may therefore interact with cumulative stress to buffer the stress-cognition relationship. The objective of the current study was to examine the moderating role of a healthy lifestyle, comprised of physical activity, social engagement, and sleep quality, in the relationship between cumulative stress exposure (CSE) and baseline and change in cognitive performance (global cognition, episodic memory, executive function) over 9 years among 1,297 older adults in the Midlife in the United States cohort (Mage = 69.0 ± 6.4, 57.8% female). METHODS: CSE and healthy lifestyle behaviors were indexed using self-reported questionnaires at baseline, and cognitive function was assessed using a battery of standardized neuropsychological tests at baseline and follow-up. RESULTS: Controlling for age, sex, education, race, marital status, employment status, hypertension, diabetes, and depression, higher CSE was associated with poorer baseline performance and slower decline over time in global cognition and executive function, but not episodic memory. A healthy lifestyle did not significantly moderate the relationship between cumulative stress and cognitive function. Exploratory analyses showed a significant cumulative stress-cognition relationship among females only. DISCUSSION: This study lends support for a lifespan model of cognitive aging and suggests that the cognitive health consequences of stress extend beyond immediate timescales.

Neuroticism and Stress in Older Adults: The Buffering Role of Self-Esteem.

BACKGROUND: Chronic stress is associated with accelerated aging and poor health outcomes in older adults. According to the Transactional Model of Stress (TMS), distress is experienced when one perceives the stressor, or threat, to outweigh the ability to cope. The experience of distress is correlated with trait neuroticism, which is associated with greater perceptions of stress and stress reactivity, as well as a tendency to engage in maladaptive coping strategies. However, as individual personality traits do not act in isolation, this study aimed to investigate the moderating role of self-esteem in the relationship between neuroticism and distress using a TMS framework. METHODS: A total of 201 healthy older adults (Mage = 68.65 years) completed questionnaires measuring self-esteem, neuroticism, perceived stress, and positive coping. RESULTS: Greater neuroticism was significantly associated with less positive coping at low (b = -0.02, p < 0.001) and mean self-esteem levels (b = -0.01, p < 0.001), but not at high self-esteem levels (b = -0.01, p = 0.06). No moderating effect was found for perceived stress or overall distress. CONCLUSION: The results support the association between trait neuroticism and indices of stress and suggest a potential buffering effect of self-esteem in moderating the negative association between neuroticism and positive coping.

The association between Mediterranean diet adherence and allostatic load in older adults.

Allostatic load (AL) is a multisystemic index of biological wear and tear which is associated with poor health outcomes. In recent years, researchers have examined the association between dietary pattern intake and AL; however, no studies to date have examined the relationship between AL and consumption of a Mediterranean diet. Blood and urine samples were collected from 201 community-dwelling older adults who completed a Food Frequency Questionnaire (FFQ). A Mediterranean Diet Score (MDS) was calculated based on previous recommendations and a sex-based AL index was calculated using a count-based approach for 16 biomarkers associated with neuroendocrine, immune, cardiovascular, or metabolic function. It was hypothesized that a higher MDS would be associated with lower AL, and that this association would be particularly robust for the immune and metabolic subcomponents of the AL index. In support of the primary study hypotheses, generalized linear models revealed a significant inverse relationship between MDS and AL (ß = -0.03, P = 0.037). However, subcomponents of the AL model were not significantly associated with MDS. Exploratory sub-group analyses by sex suggested that the association between AL and MDS was more robust in male than in female participants. The current findings are interpreted with caution given the study design and sample characteristics. Nonetheless, these findings contribute to the literature supporting the Mediterranean diet as an important lifestyle behavior that may minimize AL, and therefore support healthy aging.

The mediating role of allostatic load in the relationship between early life adversity and cognitive function across the adult lifespan.

Early life adversity is consequential for poor cognitive health in mid to late-life. Early life adversity is associated with higher allostatic load, a biological indicator of physiological dysregulation due to cumulative wear-and-tear from chronic stress. Higher allostatic load is also associated with poorer cognitive function across the lifespan. To date, a paucity of research has examined allostatic load as a mechanism through which early life adversity impacts cognition in adulthood. Using cross-sectional data from the Midlife in the United States (MIDUS) Study, the objective of the current study was to investigate the mediating role of allostatic load in the relationship between early life adversity and cognitive performance (global cognition, episodic memory, executive function) among middle-aged and older adults without cognitive impairment (n = 1541, Mage=53 ± 12, 53% female). Early life adversity was measured retrospectively using the Childhood Trauma Questionnaire. Allostatic load was composed of 20 biomarker proxies of neuroendocrine, metabolic, inflammatory, and cardiovascular systems, stratified by sex. Cognitive performance was evaluated using a battery of standardized neuropsychological tests. Controlling for age, education, and race, allostatic load significantly mediated the relationship between early life adversity and global cognition (ß=-0.01, 95%CI [-0.01,-0.001]), and early life adversity and executive function (ß=-0.01, 95%CI [-0.01,-0.001]), but not episodic memory. Findings did not change after controlling for lifestyle behaviours and current depression. Consistent with the biopsychosocial lifespan model of cognitive aging, findings suggest that early life adversity may become biologically embedded over time to negatively impact cognitive function in later adulthood in a domain-specific manner.

Do group-based mindfulness meditation programs enhance executive functioning? A systematic review and meta-analysis of the evidence.

Research examining the effects of group-based mindfulness interventions on executive functioning have yielded inconsistent findings, with some reports of enhanced performance and other reports of null findings. Inconsistencies in the literature may be due to methodological differences across studies, including the type of control group employed and sample characteristics (e.g., clinical vs. non-clinical samples). The current systematic review and meta-analysis examined the effect of group-based mindfulness programs on executive functioning in persons 18+ years of age. Following the standards for systematic review, a total of 29 studies were included in the meta-analysis, of which 21 comparisons contributed to the analysis of inhibition; nine to working memory; nine to attention shifting; and four to the analysis of verbal fluency. After removing outliers, random effects models suggested a small but significant synthesized effect of group-mindfulness training on overall executive functioning (95% CI = 0.256, 0.725). Examination of executive subdomains after removing outliers suggested a small, statistically significant effect for inhibition (95% CI = 0.055, 0.387), working memory (95% CI = 0.010, 0.437), and verbal fluency (95% CI = 0.071, 1.931). No significant pooled effects were found for attention shifting. A priori subgroup analysis by randomization, type of control group, and sample cohort revealed inconsistent results. Overall, the current review suggests that the effect of group-based mindfulness training on executive functioning is not robust.

Virtual tourism for older adults living in residential care: A mixed-methods study.

Due to financial and mobility barriers, a majority of older adults living in collective dwellings are no longer able to engage in tourism, a leisure activity that contributes to quality of life and wellbeing. Immersive Virtual Reality (VR) may serve as a programmatic tool to facilitate tourism. This pilot study examined the effects of VR tourism exposure on indices of psychosocial wellbeing among older adults living in residential care. Using a mixed-methods study design, 18 older adults were exposed to VR tourism three times a week, over six weeks. Participants reported decreased anxiety and fatigue immediately following exposure, and increased social engagement and quality of life following six weeks of VR tourism. Qualitative data offered additional insight on the process by which VR tourism may enhance wellbeing. Findings suggest that immersive VR tourism may be a viable program for older adults in residential care.

Examining the Moderating Role of a Mediterranean Diet in the Relationship Between Perceived Stress and Cognitive Function in Older Adults.

OBJECTIVES: Perceived stress and adherence to a Mediterranean diet pattern have been identified as independent predictors of cognitive function in older adulthood; however, no studies to date have examined the interaction between perceived stress and diet adherence on cognitive health. This cross-sectional study investigated the synergistic effect of perceived stress and adherence to a Mediterranean diet pattern on cognitive function in 192 nondemented older adults aged 60-95 years. METHOD: Participants completed a Food Frequency Questionnaire (FFQ) and the Perceived Stress Scale (PSS-10). Executive functioning was assessed using the Trail Making Test-Part B (TMT-B) and episodic memory was assessed using the immediate and delayed free recall subscales from the California Verbal Learning Test (CVLT-II). RESULTS: Moderation analyses revealed that higher perceived stress was associated with worse executive functioning at low levels of Mediterranean diet adherence (B = 1.75, SE = 0.67, p = .009), but not at moderate and high levels of Mediterranean diet adherence (ps > .05). Perceived stress was not associated with episodic memory, irrespective of Mediterranean diet adherence. DISCUSSION: Findings provide preliminary evidence that the association between higher perceived stress and poorer executive function may be dependent on diet intake. Additional research is needed to confirm these findings.

The association between allostatic load and cognitive function: A systematic and meta-analytic review.

Previous research suggests that high allostatic load (AL), a biological indicator of physiological dysregulation due to chronic stress, is associated with poor cognitive functioning. To date, no studies have systematically reviewed the literature to evaluate the strength and consistency of this relationship. The objective of this study was to conduct a systematic and meta-analytic review of studies that have investigated the association between AL and performance on standardized cognitive tests among adults aged 18 years and older. A total of 18 studies were retained for review. Meta-analyses revealed a significant cross-sectional association between higher AL and poor global cognition (r = -0.08, p <  0.001) and executive function (r = -0.07, p =  0.02), but not memory (r = -0.07, p =  0.10). Due to variation in statistical methods used, longitudinal meta-analyses were not performed. Qualitative review of the literature suggests that AL algorithm, physiological systems and individual biomarkers included in the AL index, and sample age may be key moderators of the AL-cognition relationship. Although the magnitude of reported associations is small, findings support AL as a robust indicator of cognitive function among adults. Study limitations and future directions are discussed.

Sex differences in the relationship between dietary pattern adherence and cognitive function among older adults: findings from the NuAge study.

BACKGROUND: Consumption of a prudent dietary pattern rich in healthy nutrients is associated with enhanced cognitive performance in older adulthood, while a Western dietary pattern low in healthy nutrients is associated with poor age-related cognitive function. Sex differences exist in dietary intake among older adults; however, there is a paucity of research examining the relationship between sex-specific dietary patterns and cognitive function in later life. METHODS: The current study aimed to investigate sex differences in the relationship between sex-specific dietary pattern adherence and global cognitive function at baseline and over a 3-year follow-up in 1268 community-dwelling older adults (Mage = 74 years, n = 664 women, n = 612 men) from the Quebec Longitudinal Study on Nutrition and Successful Aging (NuAge). A 78-item Food Frequency Questionnaire was used to estimate dietary intake over the previous year. Sex-specific dietary pattern scores were derived using principal component analysis. Global cognition was assessed using the Modified Mini-Mental State Examination (3MS). RESULTS: Adjusted linear mixed effects models indicated that a healthy, prudent dietary pattern was not associated with baseline cognitive performance in men or women. No relationship was found between Western dietary pattern adherence and baseline cognitive function in women. Among men, adherence to an unhealthy, Western dietary pattern was associated with poorer baseline cognitive function (ß = - 0.652, p = 0.02, 95% CI [- 1.22, - 0.65]). No association was found between prudent or Western dietary patterns and cognitive change over time in men or women. CONCLUSIONS: These findings highlight the importance of conducting sex-based analyses in aging research and suggest that the relationship between dietary pattern adherence and cognitive function in late life may be sex-dependent.

Association between BDNF Polymorphism and Hypothalamic-Pituitary-Adrenal Activity in Later Adulthood.

Stress exposure over the lifespan is robustly associated with accelerated cognitive decline in later life. Brain-derived neurotrophic factor (BDNF) is shown to regulate activity of the hypothalamic-pituitary-adrenal axis. The objective of this study was to evaluate the association betweenthe BDNF polymorphism and indices of stress among adults aged 50+. Community-dwelling middle-aged and older adults provided a blood sample for BDNF genotyping. Participants also sampled their saliva 5 times/day for 3 consecutive days for the measurement of diurnal cortisol and underwent the Trier Social Stress Test (TSST) for the measurement of stress reactivity. Among 121 adults aged 50-67 years (78% female; 89% Caucasian), 74 participants were Val/Val carriers and 47 carried 1 copy of the Met allele. Repeated-measures analyses did not reveal an association between BDNF genotype and diurnal salivary cortisol (p = 0.63); however, analyses revealed that Met+ carriers displayed lower levels of cortisol secretion in response to the TSST compared with Val/Val carriers; F(4.43, 496.238) = 2.57, p = 0.032. This is the first study to evaluate the role of the BDNF polymorphism in stress physiology among older adults. Future studies are needed to evaluate the lifespan interconnections between BDNF and stress physiology.

A systematic review of existing peripheral biomarkers of cognitive aging: Is there enough evidence for biomarker proxies in behavioral modification interventions?: An initiative in association with the nutrition, exercise and lifestyle team of the Canadian Consortium on Neurodegeneration in Aging.

Peripheral biomarkers have shown significant value in predicting brain health and may serve as a useful proxy measurement in the assessment of evidence-based lifestyle behavior modification programs, including physical activity and nutrition programs, that aim to maintain cognitive function in late life. The aim of this systematic review was to elucidate which peripheral biomarkers are robustly associated with cognitive function among relatively healthy non-demented older adults. Following the standards for systematic reviews (PICO, PRIMSA), and employing MEDLINE and Scopus search engines, 222 articles were included in the review. Based on the review of biomarker proxies of cognitive health, it is recommended that a comprehensive biomarker panel, or biomarker signature, be developed as a clinical end point for behavior modification trials aimed at enhancing cognitive function in late life. The biomarker signature should take a multisystemic approach, including lipid, immune/inflammatory, and metabolic biomarkers in the biological signature index of cognitive health.