High-Density Lipoprotein Cholesterol Level Relates to Working Memory, Immediate and Delayed Cued Recall in Brazilian Older Adults: The Role of Cognitive Reserve

Cognitive impairment and depression precede increased HDL-C levels in middle-aged and older Chinese adults: cross-lagged panel analyses

BACKGROUND

High-density lipoprotein cholesterol (HDL-C) is widely recognized for its protective effects against cognitive decline. However, recent studies have presented conflicting results, with some suggesting no significant cognitive benefits or even an increased risk of dementia associated with high HDL-C levels. For those who suffer from depression, the cognitive benefits of HDL-C may be diminished or reversed. The purpose of this study is to investigate the associations between HDL-C, cognitive ability, and depressive symptoms in middle-aged and older Chinese adults.

METHODS

The datasets utilized were sourced from the China Health and Retirement Longitudinal Study (CHARLS) for the years 2011 and 2015, comprising 4,302 participants. Cross-lagged models were employed to explore the temporal sequence between cognitive performance and HDL-C levels, and to examine the interplay among depression, cognition, and HDL-C. Confounding factors such as sociodemographic characteristics, sleep conditions, and history of chronic diseases were controlled for.

RESULTS

The analysis revealed unidirectional effects of baseline impaired cognition and greater severity of depression on increased HDL-C levels at follow-up (β =  - 0.036 and β = 0.028, respectively, P < 0.05). However, higher baseline HDL-C levels did not significantly predict cognitive performance or depression 4 years later (β =  - 0.008 and β = 0.023, respectively, P > 0.05). Depressive symptoms and cognition were found to have a significant bidirectional association (β =  - 0.026 and β =  - 0.053, respectively, P < 0.05).

CONCLUSIONS

Cognitive impairment and depression are associated with higher HDL-C levels, whereas higher HDL-C levels do not appear to protect against cognitive decline or depressive symptoms. These findings underscore the importance of preserving cognitive and mental health, which may lower the likelihood of cardiovascular disease and dementia. Future studies should validate these findings and develop targeted interventions tailored to specific populations.

Associations between circulating cardiovascular disease risk factors and cognitive performance in cognitively healthy older adults from the NuAge study

Introduction

Cardiovascular disease risk factors (CVRFs) contribute to the development of cognitive impairment and dementia.

Methods

This study examined the associations between circulating CVRF biomarkers and cognition in 386 cognitively healthy older adults (mean age = 78 ± 4 years, 53% females) selected from the Quebec Longitudinal Study on Nutrition and Successful Aging (NuAge). Memory, executive function, and processing speed were assessed at baseline and 2-year follow-up. CVRF biomarkers included total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglycerides, glucose, insulin, high sensitivity C-reactive protein (hs-CRP), homocysteine, protein carbonyls, and cortisol. Linear mixed models were used to determine associations between individual CVRF biomarkers and cognition at both time points.

Results

HDL-C was most consistently associated with cognition with higher values related to better performance across several domains. Overall, stronger and more consistent relationships between CVRF biomarkers and cognition were observed in females relative to males.

Discussion

Findings suggest that increases in the majority of circulating CVRFs are not associated with worse cognition in cognitively healthy older adults.

Lipoprotein(a) and risk of cognitive impairment in Black and White Americans: the Reasons for Geographic and Racial Differences in Stroke cohort

Background

Cognitive impairment has a substantial vascular etiology. Higher lipoprotein(a) [Lp(a)] is associated with cardiovascular disease risk, but its association with cognitive function is uncertain. We hypothesized that Lp(a) is a risk factor for cognitive impairment, a relationship that would be modified by race and sex.

Objectives

To study the association of Lp(a) with cognitive impairment in a biracial cohort.

Methods

The Reasons for Geographic and Racial Differences in Stroke (REGARDS) study recruited 30,239 Black and White Americans aged >45 years from 2003 to 2007. After 3.4 years, among participants with normal baseline cognition, baseline Lp(a) was measured in 434 cases of incident cognitive impairment and 557 controls. Cognitive impairment was defined as scores below the sixth percentile based on age, sex, race, and education norms on 2 or 3 components of a 3-test battery administered every 2 years.

Results

Median Lp(a) was higher in Black than in White individuals. Among Black participants, the adjusted odds ratio (OR) of cognitive impairment per SD higher increment Lp(a) was 1.39 (95% CI: 1.05, 1.84). The OR in White participants was 1.03 (95% CI: 0.87, 1.21; P for race difference = .03). The relationship of Lp(a) with cognitive trajectory differed by sex and race. Elevated Lp(a) was associated with worse baseline memory in Black men and a steeper trajectory of verbal fluency decline in Black men than in White men and women.

Conclusion

Higher Lp(a) was associated with increased risk of cognitive impairment in Black but not White individuals. Future studies should evaluate the biological and social mechanisms through which race and Lp(a) interact to increase risk of cognitive impairment.

NHANES 2011-2014 Reveals Decreased Cognitive Performance in U.S. Older Adults with Metabolic Syndrome Combinations

A relationship between metabolic syndrome and cognitive impairment has been evidenced across research; however, conflicting results have been observed. A cross-sectional study was conducted on 3179 adults older than 60 from the 2011-2014 National Health and Nutrition Examination Survey (NHANES) to analyze the relationship between metabolic syndrome and cognitive impairment. In our results, we found that adults with abdominal obesity, high triglycerides, and low HDL cholesterol had 4.39 fewer points in the CERAD immediate recall test than adults without any metabolic syndrome factors [Beta = -4.39, SE = 1.32, 17.75 (1.36) vs. 22.14 (0.76)]. In addition, people with this metabolic syndrome combination exhibited 2.39 fewer points in the CERAD delayed recall test than those without metabolic syndrome criteria [Beta = -2.39, SE = 0.46, 4.32 (0.49) vs. 6.71 (0.30)]. It was also found that persons with high blood pressure, hyperglycemia, and low HDL-cholesterol levels reached 4.11 points less in the animal fluency test than people with no factors [Beta = -4.11, SE = 1.55, 12.67 (2.12) vs. 16.79 (1.35)]. These findings suggest that specific metabolic syndrome combinations are essential predictors of cognitive impairment. In this study, metabolic syndrome combinations that included obesity, fasting hyperglycemia, high triglycerides, and low HDL-cholesterol were among the most frequent criteria observed.

The Relation of Having Experienced a Fall in the Past to Lower Cognitive Functioning in Old Age Is Mediated via Less Physical Activity Engagement as Cognitive Reserve Contributor

Physical activity and exercise contribute to the accumulation of cognitive reserve, which is instrumental for preserving cognitive health in old age. In a large sample of 701 older adults (mean age = 70.36 years), we investigated whether the relationship between having experienced a fall in the past and lower performance in cognitive functioning was mediated via less physical activity engagement as a cognitive reserve contributor. General cognition was assessed using the mini-mental state examination (MMSE), long-term memory using a word-pair delayed recall test and working memory using a backward digit-span test. In face-to-face interviews, individuals reported information on falls during the past 12 months and their habitual physical activity engagement. Our analyses demonstrated that the relationship between having experienced a fall in the past and lower performance in the cognitive functioning measures was partly mediated (by 16.3% for general cognition, 30.6% for long-term memory, and 33.1% for working memory, respectively) via less physical activity engagement. In conclusion, we suggest as a core bio-psychological mechanism that experiencing a fall at an older age is a critical life event that hinders sufficient physical activity engagement and thereby impedes cognitive reserve build-up, resulting in lower cognitive functioning outcomes.

Modifiable lifestyle factors and cognitive reserve: A systematic review of current evidence

This systematic review aims to summarize cognitive reserve (CR) evaluation approaches and to examine the role of seven selected modifiable lifestyle factors (diet, smoking, alcohol consumption, physical activity, cognitive leisure activity, sleep, and meditation) in mitigating the impacts of age- or disease-related brain changes on cognition. Eighteen population-based English empirical studies were included. We summarize the study designs and identify three CR models that were broadly used in these studies, including a residual model assessing lifestyle factors in relation to unexplained variance in cognition after accounting for brain markers, a moderation model testing whether lifestyle factors moderate the relationship between brain status and cognition, and a controlling model examining the associations between lifestyle factors and cognition when controlling for brain measures. We also present the findings for the impact of each lifestyle factor. No studies examined diet, sleep, or meditation, and only two studies focused on smoking and alcohol consumption each. Overall, the studies suggest lifestyle activity factors (physical and cognitive leisure activities) may contribute to CR and attenuate the damaging impact of brain changes on cognition. Standardized measurements of lifestyle factors and CR are needed, and mechanisms underlying CR need to be further addressed as well.

Cognitive Functioning Mediates the Association of Cognitive Reserve with Health-Related Quality of Life

We investigated whether the relations of the cognitive reserve markers education and cognitive level of work to the physical and the mental component of health-related quality of life (HRQoL) were mediated via cognitive functioning in a large sample of 701 older adults (mean age = 70.36 years, SD = 6.87). HRQoL was measured with the 12-item Short-Form Health Survey. To measure cognitive functioning, we used the COGTEL, which is a cognitive test battery assessing prospective memory, verbal short-term memory, verbal long-term memory, working memory, verbal fluency, and inductive reasoning, combined into a composite score. Individuals reported information on their education and their main profession during their working life. Mediation analyses showed that better cognitive functioning mediated the association of higher values in the cognitive reserve markers (longer education and a high cognitive level of work) with higher HRQoL. In conclusion, the present study suggests that the sustainability of cognitive functioning in old age with the help of cognitive reserve is fundamental for the sustainability of quality of life, presumably particularly for the mental HRQoL component.

Solving the Puzzle of Cognitive Reserve Effects on Cognitive Decline: The Importance of Considering Functional Impairment

AIMS

We investigated whether the longitudinal relation between cognitive reserve accumulated across the lifespan and rate of cognitive decline over 6 years differed by the individual's degree of functional impairment.

METHODS

We analyzed longitudinal data from 897 older adults (M = 74.33 years) tested on the Trail Making Test (TMT) in 2 waves 6 years apart.

RESULTS

There was a significant interaction of functional impairment with cognitive reserve on latent change in cognitive functioning. Specifically, with no functional impairment in the first wave of assessment, greater cognitive reserve accumulated across the lifespan significantly predicted a reduced cognitive decline over 6 years (i.e., smaller increase in TMT completion time). In contrast, with certain functional impairment (in at least some activities) in the first wave, greater cognitive reserve build-up predicted a steeper cognitive decline (i.e., larger increase in TMT completion time).

CONCLUSION

Individuals with greater cognitive reserve accumulated across the lifespan show a reduced cognitive decline if they still have relatively little functional impairment, while they will show a steeper decline (compared to individuals with less cognitive reserve) as soon as functional impairment becomes substantial.

Time Effects of Informal Caregiving on Cognitive Function and Well-Being: Evidence From ELSA

BACKGROUND AND OBJECTIVES

As informal caregiving becomes prevalent, its consequences for caregivers' cognitive and socioemotional functioning gain more importance for society. There are inconsistent findings regarding the direction of the impact of caregiving-whether caregiving maintains or compromises functioning-and the impact of time-whether the effects accumulate or are stable. In this study, we elucidated 3 time effects of caregiving-concurrent, cumulative, and lagged effects-on cognitive and socioemotional functioning.

RESEARCH DESIGN AND METHODS

We used data from Wave 1 (2002-2003) to Wave 8 (2016-2017) in the English Longitudinal Study of Ageing (ELSA) and latent growth curve models with the time-varying predictor to investigate 3 time effects of caregiving on cognitive function (memory and executive function) and well-being (life satisfaction and quality of life).

RESULTS

Over and beyond age effects, current caregiving (concurrent effect) was related to worse well-being and better delayed recall. Little robust cumulative effect was found on cognition and well-being. In addition, there were significant and differential lagged effects of caregiving after controlling for concurrent and cumulative effects; that is, caregiving was related to worse well-being and better memory functioning 2-4 years later.

DISCUSSION AND IMPLICATIONS

The differential concurrent and lagged effects of caregiving on cognitive and socioemotional functioning suggest separate mechanisms for different domains of functioning. The nonsignificant cumulative effects but significant lagged effects imply that even one-time caregiving has long-term (2-4 years) consequences for the caregiver's future functioning, and the mechanism of long-term caregiving effects may be more qualitative than quantitative.

The relationship of obesity predicting decline in executive functioning is attenuated with greater leisure activities in old age

Objectives: We investigated the longitudinal relationship between obesity and subsequent decline in executive functioning over six years as measured through performance changes in the Trail Making Test (TMT). We also examined whether this longitudinal relationship differed by key markers of cognitive reserve (education, occupation, and leisure activities), taking into account age, sex, and chronic diseases as covariates.Method: We used latent change score modeling based on longitudinal data from 897 older adults tested on TMT parts A and B in two waves six years apart. Mean age in the first wave was 74.33 years. Participants reported their weight and height (to calculate BMI), education, occupation, leisure activities, and chronic diseases.Results: There was a significant interaction of obesity in the first wave of data collection with leisure activities in the first wave on subsequent latent change. Specifically, obesity in the first wave significantly predicted a steeper subsequent decline in executive functioning over six years in individuals with a low frequency of leisure activities in the first wave. In contrast, in individuals with a high frequency of leisure activities in the first wave, this longitudinal relationship between obesity and subsequent decline in executive functioning was not significant.Conclusion: The longitudinal relationship between obesity and subsequent decline in executive functioning may be attenuated in individuals who have accumulated greater cognitive reserve through an engaged lifestyle in old age. Implications for current cognitive reserve and gerontological research are discussed.

Predictors of Metabolic Syndrome in Adults and Older Adults from Amazonas, Brazil

Metabolic syndrome has been considered a factor of vulnerability and a major public health problem because it increases the risk of cardiovascular disease and type 2 diabetes. The present study from Amazonas, Brazil aimed to estimate the prevalence of the individual and general components of metabolic syndrome in adults and older adults and identify the independent predictors of metabolic syndrome. The sample of the present cross-sectional study comprised 942 participants (590 women), with a mean age of 59.8 ± 19.7 (range: 17.5 to 91.8). Blood pressure in men (62.5%), abdominal obesity in women (67.3%), and lower high-density lipoprotein cholesterol (HDL-C) in both (52.2% in men and 65.0% in women) were the most prevalent individual risk factors for metabolic syndrome. Women had a higher prevalence of abdominal obesity (p < 0.001), low HDL-C (p < 0.001), and metabolic syndrome (p < 0.001) than men; however, opposite results were seen in men for blood pressure (p < 0.001). The overall prevalence of metabolic syndrome was 47.5%. Advanced age, being female, having a higher body mass index, and a having lower educational level independently increased the odds of metabolic syndrome. Due to the association of metabolic syndrome with deterioration of health status and increased vulnerability, this study sustains the need for early public health interventions in the Amazonas region.

Cognitive Reserve Mitigates Decline in Executive Functioning Following Hepatobiliary Diseases

Abstract. The cognitive reserve hypothesis postulates that lifelong cognitive stimulation establishes a buffer that is instrumental in maintaining cognitive health. To examine this conceptual proposition in detail, we applied a novel, more general conceptual view that included recent models of vulnerability and examined whether the longitudinal association between hepatobiliary diseases and later decline in executive functioning across 6 years varied by cognitive reserve. For this purpose, we investigated longitudinal data from 897 older individuals ( M = 74.33 years) tested using the Trail Making Test (TMT) in two waves 6 years apart. Individuals reported information on key commonly used indicators of lifelong cognitive reserve build-up (i.e., education, work, and participation in leisure activity) and hepatobiliary diseases. The results revealed a significant interaction of hepatobiliary diseases with participation in leisure activity on latent change in executive functioning. Specifically, only in individuals with little (but not greater) participation in leisure activity did hepatobiliary diseases significantly predict a steeper decline in executive functioning over 6 years (i.e., increases in TMT finishing time). In conclusion, the unfavorable aftereffects of hepatobiliary diseases on a later decline in executive functioning seem to be mitigated in individuals who have built up greater cognitive reserve via participation in leisure activity during their life.

Cognitive Reserve Moderates the Predictive Role of Memory Complaints for Subsequent Decline in Executive Functioning

Aims

We investigated whether the longitudinal relation between memory complaints and subsequent decline in executive functioning over 6 years differed by leisure activity engagement as major contributor to cognitive reserve in old age.

Methods

We analyzed longitudinal data from 897 older adults (M = 74.33 years) tested on the Trail Making Test (TMT) in two waves 6 years apart. Participants reported information on memory complaints and leisure activity engagement.

Results

There was a significant interaction of memory complaints with leisure activity engagement on latent change in executive functioning. Specifically, only for individuals with less (but not those with greater) leisure activity engagement, memory complaints significantly predicted a steeper subsequent decline in executive functioning across 6 years (i.e., increases in TMT completion time).

Conclusion

The role of memory complaints as an early predictor of decline in executive functioning seems to vary by individuals' cognitive reserve.

The Role of HDL and HDL Mimetic Peptides as Potential Therapeutics for Alzheimer's Disease

The role of high-density lipoproteins (HDL) in the cardiovascular system has been extensively studied and the cardioprotective effects of HDL are well established. As HDL particles are formed both in the systemic circulation and in the central nervous system, the role of HDL and its associated apolipoproteins in the brain has attracted much research interest in recent years. Alzheimer’s disease (AD) is the most prevalent neurodegenerative disorder and the leading cause of dementia worldwide, for which there currently exists no approved disease modifying treatment. Multiple lines of evidence, including a number of large-scale human clinical studies, have shown a robust connection between HDL levels and AD. Low levels of HDL are associated with increased risk and severity of AD, whereas high levels of HDL are correlated with superior cognitive function. Although the mechanisms underlying the protective effects of HDL in the brain are not fully understood, many of the functions of HDL, including reverse lipid/cholesterol transport, anti-inflammation/immune modulation, anti-oxidation, microvessel endothelial protection, and proteopathy modification, are thought to be critical for its beneficial effects. This review describes the current evidence for the role of HDL in AD and the potential of using small peptides mimicking HDL or its associated apolipoproteins (HDL-mimetic peptides) as therapeutics to treat AD.

Cognitive Reserve Attenuates 6-Year Decline in Executive Functioning after Stroke

AIMS

We investigated whether the longitudinal relationship between history of stroke and subsequent decline in executive functioning over 6 years differed by cognitive reserve.

METHODS

We analyzed longitudinal data from 897 older adults (mean age, 74.33 years) tested on the Trail Making Test (TMT) in two waves 6 years apart. Participants reported information on key frequently used proxies of lifelong cognitive reserve accumulation (i.e., education, occupation, and leisure activity engagement), and history of stroke.

RESULTS

There was a significant interaction of stroke with leisure activity engagement on latent change in executive functioning. Specifically, only for individuals with low (but not those with high) leisure activity engagement, history of stroke significantly predicted a steeper subsequent decline in executive functioning across 6 years (i.e., increases in TMT completion time).

CONCLUSION

The detrimental aftereffects of stroke on subsequent decline in executive functioning may be attenuated in individuals who have accumulated greater cognitive reserve through leisure activity engagement across their life.

Cognitive reserve and midlife vascular risk: Cognitive and clinical outcomes

OBJECTIVE

Examine whether cognitive reserve moderates the association of 1) vascular risk factors and 2) white matter hyperintensity burden with risk of clinical progression and longitudinal cognitive decline.

METHODS

BIOCARD Study participants were cognitively normal and primarily middle-aged (M = 57 years) at baseline and have been followed with annual cognitive and clinical assessments (M = 13 years). Baseline cognitive reserve was indexed with a composite score combining education with reading and vocabulary scores. Baseline vascular risk (N = 229) was assessed with a composite risk score reflecting five vascular risk factors. Baseline white matter hyperintensity load (N = 271) was measured with FLAIR magnetic resonance imaging. Cox regression models assessed risk of progression from normal cognition to onset of clinical symptoms of Mild Cognitive Impairment. Longitudinal mixed effects models measured the relationship of these variables to cognitive decline, using a global composite score, and executive function and episodic memory sub-scores.

RESULTS

Both vascular risk and white matter hyperintensities were associated with cognitive decline, particularly in executive function. Higher vascular risk, but not white matter hyperintensity burden, was associated with an increased risk of progression to Mild Cognitive Impairment. Higher cognitive reserve was associated with a reduced risk of symptom onset and higher levels of baseline cognition but did not modify the associations between the vascular risk score and white matter hyperintensities with clinical progression or cognitive decline.

INTERPRETATION

Although cognitive reserve has protective effects on clinical and cognitive outcomes, it does not mitigate the negative impact of vascular risk and small vessel cerebrovascular disease on these same outcomes.

Cognitive Reserve Attenuates the Relation between Gastrointestinal Diseases and Subsequent Decline in Executive Functioning

AIMS

We investigated whether the longitudinal relationship between gastrointestinal diseases and subsequent decline in executive functioning over 6 years differed by cognitive reserve.

METHODS

We analyzed longitudinal data from 897 older adults (mean age 74.33 years) tested on TMT parts A and B in two waves 6 years apart. Participants reported information on education, occupation, leisure activity engagement, and gastrointestinal diseases.

RESULTS

There was a significant interaction of gastrointestinal diseases with leisure activity engagement on latent change in executive functioning. Specifically, only for individuals with low (but not those with high) leisure activity engagement, gastrointestinal diseases significantly predicted a steeper subsequent decline in executive functioning across 6 years (i.e., increases in TMT completion time).

CONCLUSION

Cognitive reserve may attenuate the detrimental influences of gastrointestinal diseases on subsequent decline in executive functioning.

Associations of Lipid Levels and Cognition: Findings from the Hispanic Community Health Study/Study of Latinos

OBJECTIVE

Hispanics/Latinos in the United States are less aware of their cholesterol levels and have a higher burden of associated adverse cardiovascular and cerebrovascular outcomes than non-Latino whites. Investigations of the associations between cholesterol levels and cognition in this population have often occurred within the context of metabolic syndrome and are limited to select lipids despite the fact that triglycerides (TGs) may be more relevant to the health of Hispanics/Latinos.

METHODS

Baseline data from the Hispanic Community Health Study/Study of Latinos, collected from 2008 to 2011, was used to investigate the associations of lipid levels (i.e., TG, total cholesterol, TC; low-density and high-density lipoprotein cholesterol, LDL-C and HDL-C) with cognition (i.e., learning, memory, verbal fluency, and digit symbol substitution, DSS), adjusting for relevant confounders.

RESULTS

In 7413 participants ages 45 to 74 years from Central American, Cuban, Dominican, Mexican, Puerto Rican, and South American backgrounds, separate, fully adjusted linear regression models revealed that TG levels were inversely associated with DSS performance; however, this relationship was no longer significant once additional cardiovascular disease risk factors were added to the model (p = .06). TC and LDL-C levels (separately) were positively associated with learning and verbal fluency regardless of adjustments (p-values < .05). Separate analyses investigating the effect modification by background and sex revealed a particularly robust association between TC levels and DSS performance for Puerto Ricans and Central Americans (albeit in opposite directions) and an inverse relationship between TG levels and DSS performance for women (p-values < .02).

CONCLUSIONS

It is important to consider individual lipid levels and demographic characteristics when investigating associations between cholesterol levels and cognition in Hispanics/Latinos.

Improvement in verbal learning over the first year of antipsychotic treatment is associated with serum HDL levels in a cohort of first episode psychosis patients

To investigate whether changes in serum lipids are associated with cognitive performance in first episode psychosis (FEP) patients during their first year of antipsychotic drug treatment. One hundred and thirty-two antipsychotic-treated FEP patients were included through the TOP study along with 83 age- and gender-matched healthy controls (HC). Information regarding cognitive performance, psychotic symptoms, lifestyle, body mass index, serum lipids [total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein cholesterol, and triglycerides] and antipsychotic treatment was obtained at baseline and after 1 year. The cognitive test battery is comprised of assessments for verbal learning, processing speed, working memory, verbal fluency, and inhibition. Mixed-effects models were used to study the relationship between changes over time in serum lipids and cognitive domains, controlling for potential confounders. There was a significant group by HDL interaction effect for verbal learning (F = 11.12, p = 0.001), where an increase in HDL levels was associated with improvement in verbal learning in FEP patients but not in HC. Practice effects, lifestyle, and psychotic symptoms did not significantly affect this relationship. Antipsychotic-treated FEP patients who increased in HDL levels during the first year of follow-up exhibited better verbal learning capacity. Further investigations are needed to clarify the underlying mechanisms.

Relationships between dietary nutrients intake and lipid levels with functional MRI dorsolateral prefrontal cortex activation

Background

Dorsolateral prefrontal cortex (DLPFC) is a key node in the cognitive control network that supports working memory. DLPFC dysfunction is related to cognitive impairment. It has been suggested that dietary components and high-density lipoprotein cholesterol (HDL-C) play a vital role in brain health and cognitive function.

Purpose

This study aimed to investigate the relationships between dietary nutrient intake and lipid levels with functional MRI (fMRI) brain activation in DLPFC among older adults with mild cognitive impairment.

Participants and methods

A total of 15 community-dwelling older adults with mild cognitive impairment, aged ≥60 years, participated in this cross-sectional study at selected senior citizen clubs in Klang Valley, Malaysia. The 7-day recall Diet History Questionnaire was used to assess participants’ dietary nutrient intake. Fasting blood samples were also collected for lipid profile assessment. All participants performed N-back (0- and 1-back) working memory tasks during fMRI scanning. DLPFC (Brodmann’s areas 9 and 46, and inferior, middle, and superior frontal gyrus) was identified as a region of interest for analysis.

Results

Positive associations were observed between dietary intake of energy, protein, cholesterol, vitamins B6 and B12, potassium, iron, phosphorus, magnesium, and HDL-C with DLPFC activation (P<0.05). Multivariate analysis showed that vitamin B6 intake, β=0.505, t (14)=3.29, P=0.023, and Digit Symbol score, β=0.413, t (14)=2.89, P=0.045; R²=0.748, were positively related to DLPFC activation.

Conclusion

Increased vitamin B6 intake and cognitive processing speed were related to greater activation in the DLPFC region, which was responsible for working memory, executive function, attention, planning, and decision making. Further studies are needed to elucidate the mechanisms underlying the association.

The relation of close friends to cognitive performance in old age: the mediating role of leisure activities

ABSTRACTBackground:From a conceptual point of view, close friends are an important resource for promoting activity engagement in old age. Leisure activity engagement in turn is a key predictor of cognitive performance. Empirically, it remains unclear so far whether leisure activity engagement mediates between having close friends on the one hand and cognitive performance on the other, which we investigated in a large sample of older adults.

METHODS

We assessed cognitive performance (Mill Hill vocabulary scale and Trail Making Test (TMT) parts A and B) in 2,812 older adults. Participants reported information on leisure activity engagement and close friends.

RESULTS

A larger number of leisure activities and a larger number of close friends were significantly related to better cognitive performance in the Mill Hill vocabulary scale and TMT parts A and B. A larger number of close friends were significantly related to a larger number of leisure activities. The number of leisure activities mediated more than half of the relation of the number of close friends to performance in all three cognitive measures.

CONCLUSIONS

Having close friends may be helpful to stimulate and promote activity participation in old age. By enhancing individuals' cognitive reserve, this may finally preserve their cognitive performance level in old age.

Cognitive Reserve and Social Capital Accrued in Early and Midlife Moderate the Relation of Psychological Stress to Cognitive Performance in Old Age

AIMS

The present study set out to investigate the relation of psychological stress to cognitive performance and its interplay with key life course markers of cognitive reserve and social capital in a large sample of older adults.

METHODS

We assessed cognitive performance (verbal abilities and processing speed) and psychological stress in 2,812 older adults. The Participants reported information on education, occupation, leisure activities, family, and close friends.

RESULTS

Greater psychological stress was significantly related to lower performance in verbal abilities and processing speed. Moderation analyses suggested that the relations of psychological stress to cognitive performance were reduced in individuals with higher education, a higher cognitive level of the first profession practiced after education, a larger number of midlife leisure activities, a larger number of significant family members, and a larger number of close friends.

CONCLUSION

Cognitive reserve and social capital accrued in early and midlife may reduce the detrimental influences of psychological stress on cognitive functioning in old age.

The role of cognitive reserve accumulated in midlife for the relation between chronic diseases and cognitive decline in old age: A longitudinal follow-up across six years

OBJECTIVES

The present study set out to investigate relations of the number of chronic diseases (as a global indicator of individuals' multimorbidity) to cognitive status and cognitive decline over six years as measured by changes in Trail Making Test (TMT) completion time in old adults and whether those relations differed by key life course markers of cognitive reserve (education, occupation, and cognitively stimulating leisure activities).

METHOD

We analyzed data from 897 participants tested on TMT parts A and B in two waves six years apart. Mean age in the first wave was 74.33 years. Participants reported information on chronic diseases, education, occupation, and cognitively stimulating leisure activities.

RESULTS

Latent change score modeling testing for moderation effects revealed that a larger number of chronic diseases significantly predicted stronger increase in TMT completion time (i.e., steeper cognitive performance decline). Notably, the detrimental relation of the number of chronic diseases to stronger increase in TMT completion time (i.e., cognitive performance decline) was significantly stronger in individuals with less engagement in cognitively stimulating leisure activities in midlife.

DISCUSSION

Present data suggest that disease-related cognitive decline may be steeper in individuals who have accumulated less cognitive reserve in midlife. However, greater midlife activity engagement seemed to be associated with steeper cognitive decline in any case. Implications for current cognitive reserve and neuropsychological aging research are discussed.

Associations of dyslipidaemia and lipid-lowering treatment with risk of postoperative cognitive dysfunction: a systematic review and meta-analysis

BACKGROUND

Lipid imbalance is linked to age-related cognitive impairment, but its role in postoperative cognitive dysfunction (POCD) is unknown. Here, we present a systematic review and meta-analysis on dyslipidaemia, lipid-lowering treatment and POCD risk.

METHODS

PubMed, Ovid SP and Cochrane databases were searched for longitudinal studies that reported on associations of any measure of dyslipidaemia and/or lipid-lowering treatment with POCD as relative risks (RRs) or ORs. Fixed-effects inverse variance models were used to combine effects.

RESULTS

Of 205 articles identified in the search, 17 studies on 2725 patients (grand mean age 67 years; mean age range 61-71 years) with follow-up periods of 1 day to 4 years (median 7 days; IQR 1-68 days) were included. Studies focused almost exclusively on hypercholesterolaemia as a measure of dyslipidaemia and on statins as lipid-lowering treatment. Across 12 studies on hypercholesterolaemia, we found no association with POCD risk (RR 0.93; 95% CI 0.80 to 1.08; P=0.34). Statin use before surgery was associated with a reduced POCD risk across eight studies (RR 0.81; 95% CI 0.67 to 0.98; P=0.03), but data on treatment duration were lacking.

CONCLUSION

Statin users appear to be at reduced risk of POCD although hypercholesterolaemia per se may not be associated with POCD risk. Trial studies are needed to evaluate the usefulness of statins in POCD prevention.