Function In Older Adults Research Articles

Baduanjin Exercise Improves Cognitive Function in Older Adults With Mild Cognitive Impairment: A Systematic Review and Meta-analysis.

As a nonpharmacological method for cognitive rehabilitation, older adults with mild cognitive impairment (MCI) may benefit from Baduanjin exercise (BE), a moderate-intensity aerobic exercise. This meta-analysis was conducted to determine if BE is effective in enhancing cognitive performance in older adults with MCI. Using a combination of topic phrases and free words, systematic searches were executed in nine databases. Review Manager 5.4 was used to retrieve and statistically evaluate the data. Fourteen randomized controlled studies comprising 994 individuals aged ≥60 years were included in the meta-analysis. BE enhanced the general cognitive performance in individuals with MCI as measured by the Montreal Cognitive Assessment (standardized mean difference [SMD] = 2.56; 95% confidence interval [CI], 2.17, 2.96; p < 0.001). The level of memory decline (Wechsler Memory Scale; SMD = 12.46; 95% CI, 8.36, 16.57; p < 0.001), executive function (Trail Making Test; SMD = -7.08; 95% CI, -11.21, -2.94; p < 0.001), and frailty (Edmonton Frailty Scale; SMD = -0.97; 95% CI, -1.30, -0.64; p < 0.001) were all improved with BE for older adults with MCI. This study presented a therapeutic practice guide for using BE for cognitive rehabilitation in older adults. BE notably improves cognitive function in older adults with MCI and can be an excellent nonpharmaceutical therapy option.

Neuroprotective Dietary Patterns and Longitudinal Changes in Cognitive Function in Older Adults

BackgroundNumerous studies have examined the association between neuroprotective diets and cognitive function during aging; however, these studies have produced divergent findings. Some studies find that greater adherence to these dietary patterns is associated with preserved cognition, whereas others find no effect. ObjectiveThe aim of this study was to examine the association of the Mediterranean, the Dietary Approach to Stop Hypertension (DASH), and Mediterranean-DASH Intervention for Neurodegeneration Delay (MIND) dietary patterns with global cognition over 4 waves of data from the Health and Retirement Study, a longitudinal panel study conducted at the University of Michigan. DesignThis is a longitudinal secondary data analysis using Health and Retirement Study data drawn from the Food Frequency Questionnaire completed as part of the Health Care and Nutrition Survey administered in 2013 to 2014, neuropsychological assessment data obtained from the Core questionnaire in 2014, 2016, 2018, and 2020, and demographic data from the Core questionnaire in 2014. Participants/settingParticipants with total daily energy intake below 600 or 800 kcal and above 6000 and 8000 kcal for women and men, respectively, were excluded based on criteria from a similar study using the same dataset. In addition, participants with a diagnosis of dementia, Alzheimer disease, or stroke as of 2014 were excluded. There were 6154 participants in the Mediterranean diet and DASH diet analyses and 5143 participants in the MIND diet analyses. Main outcome measureA global cognitive measure incorporating immediate and delayed recall, serial 7s, and backward counting scores was calculated for each participant at each wave. Statistical analysisThe primary analyses examined the association between each diet type and cognition over 4 waves using separate multilevel models that controlled for age, gender, self-rated health, years of education, total energy intake, weekly exercise, and body mass index. ResultsMediterranean and DASH diet adherence were positively and significantly associated with baseline cognition and were associated with slower cognitive decline over a 6-year period. MIND diet adherence was positively and significantly correlated with baseline cognition but was not significantly associated with slower cognitive decline over a 6-year period. Cross-level interactions for adherence to each dietary pattern and cognitive change over time, computed with standardized diet scores, were as follows: Mediterranean diet (β = .03; P = .002), DASH diet (β = .04; P = .004), and MIND diet (β = .02; P = .094). ConclusionsThe Mediterranean, DASH, and MIND dietary patterns are associated with better cognitive performance at baseline and the Mediterranean and DASH diets were associated with slower cognitive decline over time. Adherence to the DASH diet had the greatest magnitude of association with baseline cognition and rate of cognitive change.

Association between geriatric nutritional risk index and cognitive function in older adults with/without chronic kidney disease.

Cognitive impairment is highly prevalent among patients with chronic kidney disease, who face an increased risk of cognitive decline. The aim of this study was to investigate the relationship between the Geriatric Nutritional Risk Index (GNRI) and cognitive function in older individuals, both with and without chronic kidney disease (CKD). In this study, we analyzed data from 2728 participants in the 2011-2014 National Health and Nutrition Examination Survey (NHANES). Cognitive function was measured using the Consortium to Establish a Registry for the Alzheimer's Disease Word Learning subtest (CERAD W-L), the animal fluency test (AFT), the digit symbol substitution test (DSST), and the global cognitive z-score. The GNRI, representing whole-body nutritional status, was calculated based on serum albumin, body weight, and ideal body weight. We employed weighted multiple linear regression analyses and subgroup analyses to assess the independent association of GNRI with cognitive function in CKD and non-CKD populations. Smoothing techniques were used to fit curves, and interaction tests were used to assess the robustness and specificity of the findings. Our analyses revealed a significant positive association between higher GNRI levels and cognitive function in the older US population (for global z-score: β=0.01; 95% confidence interval [CI]=0.00, 0.01). This association remained consistent across various subgroup analyses, including those for different gender groups, age groups, smoking statuses, diabetes statuses, hypertension statuses, individuals with a BMI below 25, individuals who consumed alcohol, and non-Hispanic white individuals. Smoothed curve-fitting analyses indicated that the GNRI was linearly related to cognitive function. No statistically significant interactions were detected among these variables. Our findings emphasize the positive association between GNRI and cognitive health in individuals with or without CKD, especially when combined with other risk factors. Consequently, enhancing the nutritional status of the elderly may serve as a viable strategy to thwart the onset of cognitive decline.

Effect of intranasal insulin on perioperative cognitive function in older adults: a randomized, placebo-controlled, double-blind clinical trial.

Postoperative cognitive impairment are common neural complications in older surgical patients and exacerbate the burden of medical care on families and society. A total of 140 older patients who were scheduled for elective orthopaedic surgery or pancreatic surgery with general anaesthesia were randomly assigned to Group S or Group I with a 1:1 allocation. Patients in Group S and Group I received intranasal administration of 400μL of normal saline or 40IU/400μL of insulin, respectively, once daily from 5minutes before anaesthesia induction until 3days postoperatively. Perioperative cognitive function was assessed using the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment-Basic (MoCA-B) at 1day before and 3days after surgery and postoperative delirium (POD) incidence was assessed using the 3-minute Diagnostic Interview for CAM (3D-CAM) on postoperative days 1-3. Serum levels of interleukin-6 (IL-6), tumour necrosis factor α (TNF-α), S100-β and C-reactive protein (CRP) were measured on the first day after surgery. Insulin treatment significantly increased postoperative MMSE and MoCA-B scores in group I than in group S (P < 0.001, P = 0.001, respectively), decreased the incidence of POD within the 3-day postoperative period in Group I than in Group S (10.9% vs 26.6%, P = 0.024), and inhibited postoperative IL-6 and S100-β levels in Group I compared to Group S (P = 0.034, P = 0.044, respectively). Intranasal insulin administration is thus suggested as a potential therapy to improve postoperative cognition in older patients undergoing surgery. However, a more standardized multi-centre, large-sample study is needed to further validate these results.

FC6: Impact of work activity on cognitive functioning in older adults

Objectives: The aim of this study was to analyze the impact of maintaining professional activity on cognitive functioning at advanced ages.Methods: The sample comprised 131 people aged 60 years-old and older (M = 68,15 years) of whom 41 were still working (30 women and 11 men, Mage = 65.24), and 89 retired (74 women and 15 men Mage = 69.48). To assess participants’ cognitive functioning the following instruments were used: Rey-Osterrieth Complex Figure Test, Digit Span Test, Trail Making Test (TMT), Verbal Fluency Test and Boston Naming Test (Short Form). Since age differences among participants of the two groups were found an ANCOVA test was used, and age was included as a covariable.Results: Statistically significant differences were found between the two groups in the Part A of TMT (F = 7.383, p &lt; 0.05) and the Boston Naming Test (Short Form) (F = 3.495, p &lt; 0.05). Compared with retired participants those who were still active had better scores on both measures.Conclusions: Work-related activity in old age has a positive influence on cognitive functioning and can contribute to older people’s cognitive reserve and to maintaining better attention, naming or word retrieval performance. Thus, in order to maintain good cognitive functioning, when older adults retire, they may need to substitute work with stimulating and challenging activities.

Utilizing the determinants of healthy aging to guide the choice of social prescriptions for older adults.

Executive summary: The age of Canada's population is increasing, necessitating innovative methods and tools for assessing the needs of older adults and identifying effective health and social prescriptions. In Alberta, a community-based, senior-serving organization undertook the development and piloting of the Healthy Aging Asset Index, an assessment tool and social prescribing guide for use by a variety of professionals within the community. Tool development was rooted in medical complexity assessment and social work practice, and adhered to the determinants of healthy aging established by Alberta's Healthy Aging Framework, which is based on the determinants of healthy aging published by the World Health Organization. Results from the pilot showed improvement in the functionality of older adults within the determinants over time, as they were supported in addressing areas of personal vulnerability. Adopting tools such as the Healthy Aging Asset Index can bring cohesiveness to the support that older adults receive across the care continuum and has the potential to shift the balance of care away from the health system and towards the community, thus improving the capacity of health systems and government to meet the needs of Canada's older adults.

The Effects of Aerobic Exercise Interventions on Cognitive Functions in Older Adults with Mild Cognitive Impairment: A Systematic Review and Meta-Analysis

The Effects of Aerobic Exercise Interventions on Cognitive Functions in Older Adults with Mild Cognitive Impairment: A Systematic Review and Meta-Analysis

Current Trends of Exercise Programs for Improving Cognitive Function in Older Adults

PURPOSE: Limited studies have analyzed exercise protocols for cognitive improvement in older adults. Therefore, we closely examined the composition, content, and operation methods of these exercise programs to identify current trends.METHODS: We searched the Web of Science, PubMed, and Google Scholar databases for studies published between 2019 and 2024. The search terms used included “older adults”, “cognitive function”, “mild cognitive impairment”, “dementia”, “exercise”, “physical activity”, and other related terms, in both Korean and English.RESULTS: Aerobic exercises primarily comprised step-based exercises (walking and stepping) and dance routines, typically lasting 15-60 minutes per session, 1-3 times per week for 6-24 weeks, regardless of the individual’s cognitive level. Assistant instructors often participated, and in cases of severe cognitive impairment, patients’ caregivers also participated. Resistance exercises were most often performed using body weight and elastic bands, along with other tools and equipment, such as balls, water bottles, or specialized equipment. The exercises commonly involved 8-12 repetitions, 2-3 sets, with 1-minute rest between sets. Several programs included functional exercises to improve daily living performance. Other activities that were incorporated into the exercise programs included exergames and balance, mind-body, peripheral, and eye exercises.CONCLUSIONS: Recent cognitive exercise programs for older adults typically last three months and use a variety of tools or digital technologies within the scope of older adult exercise guidelines. Exercises for people with severe cognitive impairment tend to be more individualized, gradual, and flexible in their approach.

Identifying exercise and cognitive intervention parameters to optimize executive function in older adults with mild cognitive impairment and dementia: a systematic review and meta-analyses of randomized controlled trials

Physical exercise is recognized for its beneficial effects on brain health and executive function, particularly through the careful manipulation of key exercise parameters, including type, intensity, and duration. The aim of this systematic review and meta-analysis was to delineate the optimal types, intensities, and durations of exercise that improve cognitive functions in older adults with mild cognitive impairment (MCI) or dementia. A comprehensive search was conducted in Scopus, Web of Science, and PubMed from their inception until December 2023. The methodological quality and publication bias of the included studies were assessed using the PEDro scale and Egger’s regression test, respectively. Separate meta-analyses were performed to assess the overall impact of exercise on cognitive assessments and to explore the effects of different exercise types (i.e., aerobic, resistance, dual-task, mind-body, and multi-component exercises) and intensities (i.e., low, moderate, and high) on executive function. Results were presented as standardized mean differences (SMD) and 95% confidence intervals (95% CI). A meta-regression analysis was conducted to examine the correlation between exercise duration and mean effects. In total, 15,087 articles were retrieved from three databases, of which 35 studies were included in our final analyses. The results indicated high overall methodological quality (PEDro score = 8) but a potential for publication bias (t = 2.08, p = 0.045). Meta-analyses revealed that all types of exercise (SMD = 0.691, CI [0.498 to 0.885], p < 0.001) and intensities (SMD = 0.694, CI [0.485 to 0.903], p < 0.001) show significant effects favoring exercise. Notably, dual-task exercises (SMD = 1.136, CI [0.236 to 2.035], p < 0.001) and moderate-intensity exercises (SMD = 0.876, CI [0.533 to 1.219], p < 0.001) exhibited the greatest effect. No significant correlation was observed between exercise duration and SMD (R² = 0.038, p = 0.313). Overall, our meta-analyses support the role of physical exercise in enhancing executive function in older adults with MCI or dementia. It is essential to carefully tailor exercise parameters, particularly type and intensity, to meet the specific needs of older adults with MCI or dementia. Such customization is crucial for optimizing executive function outcomes and improving overall brain health.

Synergistic associations of CD33 variants and hypertension with brain and cognitive aging among dementia-free older adults: A population-based study.

CD33 rs3865444 and hypertension (HTN) are related to cognitive impairment, individually. However, little is known about their combined effects on cognitive function in older adults. This population-based study included 4368 dementia-free participants (age ≥65 years) in the Multimodal Interventions to Delay Dementia and Disability in Rural China (MIND-China), with data available in 1044 persons for gray matter volume and 85 persons for cerebral blood flow (CBF). We used general linear regression and mediation models to examine the associations of rs3865444 and HTN with cognition, brain atrophy, and CBF. Among rs3865444 CC carriers, HTN and late-life HTN were significantly associated with impaired cognition. Midlife and late-life HTN were correlated with brain atrophy. CD33 rs3865444 CC moderated the mediation effect of gray matter volume on the association between HTN and global cognition. HTN was correlated with low CBF in rs3865444 CC carriers. There are synergistic associations of CD33 rs3865444 and HTN with brain and cognitive aging in dementia-free older adults.

The influence of lighting and thermal environments on sleep and cognitive function in older adults

Recent research has demonstrated the significant influence of lighting and thermal conditions on cognitive performance and sleep quality. However, a notable gap exists in understanding how these factors impact older adults within their living environments. This study examined the relationship between daily lighting and thermal exposures with cognitive performance and sleep quality in older adults. Eighteen older adults, with a mean age of 75 (SD = 7.7, female = 13), participated in a three-day study. Throughout the protocol, their indoor lighting and thermal conditions were monitored using environmental sensors. Participants were instructed to complete a series of cognitive tasks twice a day. Additionally, they wore a smartwatch-type actigraph and a wearable light tracker to monitor their sleep/wake patterns and daily light exposure. The findings showed that appropriate nighttime lighting correlated with improved evening cognitive performance. Higher nighttime indoor lighting intensity positively correlated with cognitive measures, while nighttime correlated color temperature (CCT) exposure had negative correlations. Daytime melanopic equivalent daylight illuminance (MEDI) exposure significantly predicted total sleep time, with increased circadian-effective light exposure reducing sleep fragmentation. Conversely, higher nighttime lighting intensity was linked to decreased sleep efficiency. Higher bedroom temperatures were associated with improved sleep efficiency and reduced fragmentation. These findings highlight the importance of optimizing lighting conditions and maintaining comfortable temperatures in residential environments to promote cognitive performance and sleep quality among older adults.

Association between Life's Essential 8 and cognitive function among older adults in the United States

The American Heart Association (AHA) recently redefined cardiovascular health (CVH) with the introduction of Life's Essential 8 (LE8), which encompasses eight areas (diet, physical activity, nicotine exposure, sleep duration body mass index, non-HDL cholesterol, blood glucose, and blood pressure). This study aimed to explore the relationships between both the aggregate and individual CVH metrics, as defined by Life's Essential 8, and cognitive function in older adults in the United States. This cross-sectional, population-based study analyzed data from the National Health and Nutrition Examination Survey conducted between 2011 and 2014, focusing on individuals aged 60 years and older. CVH was categorized as low (0–49), moderate (50–79), or high (80–100). Cognitive function was assessed through the CERAD tests, Animal Fluency test, and Digit Symbol Substitution test. Multivariable logistic models and restricted cubic spline models were employed to investigate these associations. This study included a total of 2279 older adults in the United States. Only 11% of adults achieved a high total CVH score, while 12% had a low score. After further adjustment for potential confounding factors, higher LE8 scores were significantly associated with higher scores on CERAD: delayed recall score (0.02[0.01, 0.03]; P < 0.001), CERAD: total score (3 recall trials) (0.04[0.02, 0.06]; P < 0.001), animal fluency: total score (0.09[0.05, 0.12]; P < 0.001), and digit symbol: score (0.29[0.18, 0.41]; P < 0.001), demonstrating a linear dose–response relationship. Similar patterns were also observed in the associations between health behavior and health factor scores with cognitive function tests. LE8 scores exhibited positive linear associations with cognitive function. Maintaining better levels of CVH may be associated with higher levels of cognitive function in older Americans, but further research is needed to confirm the causal and temporal relationships between LE8 and cognitive function.

Tongue brushing enhances the myoelectric activity of the suprahyoid muscles in older adults: a six-week randomized controlled trial

Tongue brushing improves respiratory function in older adults. Considering connection between the respiratory-related and suprahyoid muscles, this study aimed to investigate whether tongue-brushing interventions can improve myoelectric activity during respiration. A six-week randomized controlled trial was conducted in Kitakyushu, Japan, with 50 participants aged ≥ 65 years. The participants were allocated to the intervention (tongue brushing with routine oral hygiene) or control (routine oral hygiene alone) groups. Surface electromyography (sEMG) was used to assess the myoelectric activity of the suprahyoid muscles during inhalation, exhalation, and forced vital capacity (FVC). A survey was conducted at baseline and the end of the follow-up period. Thirty-six participants were recruited for the analysis. The root mean squares (RMS) of sEMG during exhalation increased significantly at the end of the follow-up period compared with that at baseline in the intervention group [48.7 (18.0–177.5) vs. 64.9 (21.6–163.0), p = 0.001], but not in the control group. The generalized linear model revealed that the ratio of change in FVC was correlated with the change in the RMS of sEMG of the suprahyoid muscles during exhalation after adjusting for potential confounders. Tongue brushing enhances the myoelectric activity of the suprahyoid muscle.

Joint Trajectories of Performance-Based and Self-Reported Physical Functioning in Older Adults: A 20-Year Longitudinal Study in the Netherlands.

The well-known disablement process has been conceptualized as a series of transitions between progressive states of functional decline. We studied joint patterns of change within disablement states defined as walking speed, grip strength, and self-reported disability. 1702 participants aged 65 and over were included from the Longitudinal Aging Study Amsterdam, spanning seven waves over 20 years (1996-2016). Group-based multi-trajectory modeling yielded trajectory clusters (TCs) of different patterns of change, further characterized by baseline sociodemographic characteristics, physical and cognitive health, and survival rate. Five TCs were identified, distinguished by increasing baseline age. Walking speed and disability showed generally concomitant trajectories. Women had poorer trajectories in grip strength than men, but not in walking speed and disability. Poor physical health distinguished especially the poorest, and cognitive impairment distinguished especially the one-before-poorest from the better TCs. The findings suggest that the disablement states are not generally distinct or sequential.

Curcumin Supplementation and Vascular and Cognitive Function in Chronic Kidney Disease: A Randomized Controlled Trial.

Chronic kidney disease (CKD) increases the risk of cardiovascular disease and cognitive impairment. Curcumin is a polyphenol that improves vascular and cognitive function in older adults; however, its effects on vascular and cognitive function in patients with CKD are unknown. We hypothesized that curcumin supplementation would improve vascular and cognitive function in patients with CKD. Eighty-eight adults diagnosed with stage 3b or 4 CKD (aged 66 ± 8 years, 75% male) participated in a 12-month, randomized, double-blind, placebo-controlled study to test the effects of curcumin (Longvida®, 2000 mg/day) on vascular and cognitive function. Our primary outcome was brachial artery flow-mediated dilation (FMD). Our secondary outcomes were nitroglycerin-mediated dilation, carotid-femoral pulse wave velocity (cfPWV), and cognitive function assessed via the NIH Toolbox Cognition Battery. At baseline, the mean estimated glomerular filtration rate was 34.7 ± 10.8, and the median albumin/creatinine ratio was 81.9 (9.7, 417.3). A total of 44% of participants had diabetes. Compared with placebo, 12 months of curcumin did not improve FMD (median change from baseline was -0.7 (-2.1, 1.1) and -0.1 (-1.5, 1.5) for curcumin and placebo, respectively, with p = 0.69). Similarly, there were no changes in nitroglycerin-mediated dilation, cfPWV, or cognitive outcomes. These results do not support chronic curcumin supplementation to improve vascular and cognitive function in patients with CKD.

Association between the geriatric nutritional risk index and cognitive functions in older adults: a cross-sectional study from National Health and Nutrition Examination Survey.

To investigate the associations between the geriatric nutritional risk index (GNRI) with cognitive functions among U.S. older adults. (Patients were classified into two nutrition risk groups based on the GNRI). Our analysis utilized data from the cross-sectional National Health and Nutrition Examination Survey (NHANES) conducted between 2011 and 2014. Cognitive function was measured using CERAD test, AFT and DSST. Composite z-scores were obtained by summing test-specific z-scores of the above three cognitive tests and were used to assess the global cognitive function. We employed weighted logistic regression models to evaluate the associations between GNRI and nutritional status (low and high GNRI) with cognitive function among older participants. The non-linear relationship was described using fitted smoothed curves and threshold effect analyses. Subgroup analysis and interaction tests were also conducted. This study included 2,592 older participants aged 60 years and older. After adjusting for confounding variables, the GNRI was positively associated with AFT (β = 0.05, 95% CI 0.005-0.096, p-value = 0.0285), DSST (β = 0.192, 95% CI 0.078-0.305, p-value = 0.0010) and the composite z-scores (β = 0.027, 95% CI 0.010-0.044, p-value = 0.0024). The results also showed that the high-GNRI group was significantly associated with AFT (β = 0.922, 95% CI 0.166-1.677, p-value = 0.0169), DSST (β = 2.791, 95% CI 0.884-4.698, p-value = 0.0042) and composite z-scores (β = 0.405, 95% CI 0.115-0.695, p-value = 0.0062) likewise had significant positive correlations, using the low-GNRI group as a reference. In addition, inflection points with CERAD and composite z-scores were found at GNRI of 108.016, and 105.371, respectively. Specifically, on the left side of the inflection point GNRI levels were positively correlated with CERAD and composite z-scores (CERAD β = 0.087, 95% CI 0.024-0.150, p-value = 0.0070; composite z-scores β = 0.065, 95% CI 0.040-0.091, p-value <0.0001), while on the right side of the inflection point were significantly negatively associated (CERAD β = -0.295, 95% CI -0.529 to -0.062, p-value = 0.0133, composite z-scores β = -0.050, 95% CI -0.091 to -0.008, p-value = 0.0184). Lower GNRI was associated with poorer performance in several cognitive domains. Additionally, there was a non-linear positive association between GNRI and cognitive function in normal nutritional states, for excessive GNRI may cause cognitive decline.

Unraveling the Threads: Sleep Difficulties, Neighborhood Physical Disorder, and Subjective Cognitive Decline in Older Americans.

Research suggests that the neighborhood in which people live can be a risk or protective factor for various health outcomes, including cognitive decline to Alzheimer's disease. Similar to the impact of neighborhood on health outcomes, sleep difficulties have been linked to cognitive function in older adults. However, few studies have examined how neighborhood physical disorders moderate the effects of sleep on subjective cognitive decline (SCD). The study examined the moderating effect of neighborhood factors on the relationship between sleep difficulties and SCD. Data were obtained from 2,494 respondents (1,065 males and 1,429 females) from Wave 11 of the National Health and Aging Trends (NHATS) data. Sleep difficulties were operationalized as the presence of difficulties in falling and staying asleep. Neighborhood physical disorder (e.g., vandalism, graffiti) was based on interviewer observations of respondents' neighborhoods. SCD was operationalized as subjective reports of increasing or worse memory loss in the past 12 months and present memory rating. We utilized Linear regression to test neighborhood physical disorder as a moderator of the relationship between sleep difficulties and SCD. We found a significant interaction between sleep difficulties and neighborhood physical disorder on SCD (β=0.03, SE = 0.01, 95% CI[0.00,0.51], p < 0.001). Participants who reported higher average sleep difficulties and higher levels of neighborhood physical disorder were more likely to report SCD. Our findings add to inform future health interventions and policy recommendations that address modifiable sources of cognitive decline and risk of Alzheimer's disease.

The effect of foot immersion and neck cooling on cardiac autonomic function in older adults exposed to indoor overheating: a randomized crossover trial.

Foot immersion and neck cooling are recommended cooling strategies for protecting heat-vulnerable persons during heat waves. While we recently showed that these strategies do not limit core temperature increases in older adults during prolonged heat exposure, we did observe small reductions in heart rate. Expanding on these findings, we examined the effects of foot immersion with and without neck cooling on cardiac autonomic function. Seventeen adults (9 females; 65-81 years) underwent 3 randomized, 6 h exposures to 38 °C and 35% relative humidity with: no cooling (control), foot immersion (20°C water), or foot immersion with a wet towel (20°C) around the neck. Cardiac autonomic responses were measured at baseline and end-exposure. These included heart rate variability, cardiac and systolic blood pressure responses to standing, indexed via the 30:15 ratio and supine-to-standing systolic pressure change, respectively, and baroreflex sensitivity during repeated sit-to-stand maneuvers. The 30:15 ratio was 0.04 [95% CI: 0.01, 0.07] greater with foot immersion and neck cooling (1.08 (SD: 0.04)) relative to control (1.04 (0.06); P=0.018). Similarly, standing systolic blood pressure was elevated 9 [0, 17] mmHg with foot immersion and neck cooling (P=0.043). That said, neither difference remained statistically significant after adjusting for multiplicity (Padjusted≥0.054). No differences in 30:15 ratio or standing systolic blood pressure were observed with foot immersion alone, while heart rate variability and baroreflex sensitivity were unaffected by either cooling intervention. While foot immersion with neck cooling potentially improved cardiac autonomic responses in older adults exposed to simulated indoor overheating, these effects were small and of questionable clinical importance.

The role of cognitive reserve and depression on executive function in older adults: A 10-year study from the Wisconsin Registry for Alzheimer’s Prevention

Objective: The current study examined the longitudinal relationship between cognitive reserve (CR), depression, and executive function (EF) in a cohort of older adults. Methods: 416 participants were selected from the Wisconsin Registry for Alzheimer’s Prevention. They were native English speakers, aged ≥50+, and cognitively unimpaired at baseline, with no history of neurological or other psychiatric disorders aside from depression. Depression was assessed with the 20-item Center for Epidemiologic Studies Depression Scale (CES-D). A composite score, based on the premorbid IQ (WRAT-3 Reading subtest) and years of education was used to estimate CR. Another composite score from four cognitive tests was used to estimate EF. A moderation analysis was performed to evaluate the effects of CR and Depression on EF at follow-up after controlling for age, gender, and APOE risk score. Moreover, a multinomial logistic regression was used to predict conversion to Mild Cognitive Impairment (MCI) from the healthy baseline. Results: The negative relationship between depression and EF was stronger in individuals with higher CR levels, suggesting a possible floor effect at lower CR levels. In the multinomial regression, the interaction between CR and depression predicted conversion to MCI status, indicating that lower CR paired with more severe depression at baseline was associated with a higher risk of subsequent impairment. Conclusions: This study sheds light on the intricate relationship between depression and EF over time, suggesting that the association may be influenced by varying levels of CR. Further studies may replicate these findings in clinical populations.

Independent and joint associations between urinary polycyclic aromatic hydrocarbon metabolites and cognitive function in older adults in the United States.

Polycyclic aromatic hydrocarbons (PAHs), as organic pollutants widely present in daily environments, have been shown by existing epidemiological studies to be significantly associated with deficits in learning and memory functions in children and adults. However, the association between exposure to PAHs and cognitive function in older adults remains unclear. Additionally, existing related studies have only assessed the association between individual PAH exposures and cognitive assessments, overlooking the risks posed by mixed exposures. This study aims to use three statistical models to investigate the individual and overall effects of mixed PAH exposures on the cognition of older adults in the United States. The study cohort was obtained from the NHANES database, which included individuals aged 60 and older from 2011 to 2014. Weighted generalized linear models (GLM), weighted quantile sum (WQS) models, and Bayesian kernel machine regression (BKMR) models were utilized to evaluate the connections between urinary PAH metabolites and the standardized Z-scores of four cognitive tests: Immediate Recall Test (IRT), Delayed Recall Test (DRT), Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST). Our analysis involved 899 individuals aged 60 and above. In the fully adjusted GLM, 2-hydroxynaphthalene (2-OHNa), 3-hydroxyfluorene (3-OHFlu), and 2-hydroxyfluorene (2-OHFlu) demonstrated negative associations with DSST Z-scores. In the WQS model, six urinary PAH metabolites were negatively linked to AFT Z-scores (β (95% confidence intervals [CI]): -0.120 (-0.208, -0.033), p = 0.007) and DSST Z-scores (β (95% CI): -0.182 (-0.262, -0.103), p < 0.001). In both assessments, 2-OHNa exerted the greatest influence among the urinary PAH metabolites. In the BKMR model, there was an overall negative correlation between urinary PAH metabolites and AFT and DSST Z-scores when the concentration was within the 25th to 75th percentile, where 2-OHNa dominated the main effect of the mixture. The WQS and BKMR models were adjusted for all covariates. Increased concentrations of urinary PAH metabolites are associated with cognitive decline in older adults, mainly on language ability, executive function, sustained attention, working memory, and information processing speed, with 2-OHNa playing a major effect.