Age Modulates the Association of Caffeine Intake With Cognition and With Gray Matter in Elderly Diabetics

Coffee and tea consumption and dementia risk: The role of sex and vascular comorbidities

BACKGROUND

Coffee and tea consumption has been linked to dementia. However, it remained unknown how sex and vascular risk factors modify the association. We aimed to investigate the association of coffee and tea consumption with dementia and whether sex and vascular comorbidities modified the association.

METHODS

We included 278 elderly patients with Alzheimer's disease (AD) and 102 patients with vascular dementia (VaD) from three hospitals; controls (N = 468) were recruited during the same period. We collected the frequency and amount of coffee and tea consumption and the presence of vascular comorbidities. The multinomial logistic regression model was utilized to evaluate the association of coffee and tea consumption with dementia, stratified by sex and vascular comorbidities.

RESULTS

Different combinations and quantities of coffee and tea consumption protected against AD and VaD. Consumption of ≥3 cups of coffee or tea per day was protective against AD [adjusted odds ratio (aOR) = 0.42; 95% confidence interval (CI) = 0.22-0.78)] and VaD (aOR = 0.42; 95% CI = 0.19-0.94). Stratified analyses showed that the protective effects of a higher quantity of coffee and tea against AD were more pronounced among females and individuals with hypertension. Consumption of either coffee or tea was associated with a decreased risk of VaD among diabetic participants (aOR = 0.23; 95% CI = 0.06-0.98). Hyperlipidemia modified the association of coffee or tea consumption on the risk of AD and VaD (both Pinteraction < 0.01).

CONCLUSION

The risk of AD and VaD was lower with increased consumption of coffee and tea; the impact differed by sex and vascular comorbidities including hypertension, hyperlipidemia, and diabetes.

Bitter yet beneficial: The dual role of dietary alkaloids in managing diabetes and enhancing cognitive function

With the rising prevalence of diabetes and its association with cognitive impairment, interest in the use of dietary alkaloids and other natural products has grown significantly. Understanding how these compounds manage diabetic cognitive dysfunction (DCD) is crucial. This comprehensive review explores the etiology of DCD and the effects of alkaloids in foods and dietary supplements that have been investigated as DCD therapies. Data on how dietary alkaloids like berberine, trigonelline, caffeine, capsaicin, 1-deoxynojirimycin, nuciferine, neferine, aegeline, tetramethylpyrazine, piperine, and others regulate cognition in diabetic disorders were collected from PubMed, Research Gate, Web of Science, Science Direct, and other relevant databases. Dietary alkaloids could improve memory in behavioral models and modulate the mechanisms underlying the cognitive benefits of these compounds, including their effects on glucose metabolism, gut microbiota, vasculopathy, neuroinflammation, and oxidative stress. Evidence suggests that dietary alkaloids hold promise for improving cognition in diabetic patients and could open exciting avenues for future research in diabetes management.

Coffee consumption and all-cause and cardiovascular mortality in older adults: should we consider cognitive function?

Background

The association between coffee and mortality risk has been found in most previous studies, and recent studies have found an association between coffee consumption and cognition. However, there is still a lack of research exploring whether the association between coffee and mortality is influenced by cognitive function.

Objective

The purpose of this study was to explore the association of coffee, caffeine intake in coffee and decaffeinated coffee with all-cause mortality and cardiovascular disease (CVD) mortality in older adults with different cognitive performances.

Methods

The study was based on data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. Coffee and caffeine consumption data were obtained from two 24-h dietary recalls. Individual cognitive functions were assessed by CERAD-word learning test (CERAD-WLT), animal fluency test (AFT), and digit symbol substitution test (DSST). In addition, principal component analysis (PCA) was performed with the above test scores to create global cognitive score. The lowest quartile of scores was used to classify cognitive performance. Cox regression and restricted cubic spline (RCS) were applied to assess the relationship between coffee and caffeine consumption and mortality.

Results

In the joint effects analysis, we found that those with cognitive impairment and who reported without drinking coffee had the highest risk of all-cause and cardiovascular mortality compared with others. In the analysis of population with cognitive impairment, for all-cause mortality, those who showed cognitive impairment in the AFT displayed a significant negative association between their total coffee consumption and mortality {T3 (HR [95% CI]), 0.495 [0.291-0.840], p = 0.021 (trend analysis)}. For DSST and global cognition, similar results were observed. Whereas for CERAD-WLT, restricted cubic spline (RCS) showed a "U-shaped" association between coffee consumption and mortality. For CVD mortality, a significant negative trend in coffee consumption and death was observed only in people with cognitive impairment in AFT or DSST. In addition, we observed that decaffeinated coffee was associated with reduced mortality in people with cognitive impairment.

Conclusion

Our study suggested that the association between coffee consumption and mortality is influenced by cognition and varies with cognitive impairment in different cognitive domains.

Caffeine, Postoperative Delirium And Change In Outcomes after Surgery (CAPACHINOS)-2: protocol for a randomised controlled trial

INTRODUCTION

Delirium is a major public health issue for surgical patients and their families because it is associated with increased mortality, cognitive and functional decline, prolonged hospital admission and increased healthcare expenditures. Based on preliminary data, this trial tests the hypothesis that intravenous caffeine, given postoperatively, will reduce the incidence of delirium in older adults after major non-cardiac surgery.

METHODS AND ANALYSIS

The CAffeine, Postoperative Delirium And CHange In Outcomes after Surgery-2 (CAPACHINOS-2) Trial is a single-centre, placebo-controlled, randomised clinical trial that will be conducted at Michigan Medicine. The trial will be quadruple-blinded, with clinicians, researchers, participants and analysts all masked to the intervention. The goal is to enrol 250 patients with a 1:1:1: allocation ratio: dextrose 5% in water placebo, caffeine 1.5 mg/kg and caffeine 3 mg/kg as a caffeine citrate infusion. The study drug will be administered intravenously during surgical closure and on the first two postoperative mornings. The primary outcome will be delirium, assessed via long-form Confusion Assessment Method. Secondary outcomes will include delirium severity, delirium duration, patient-reported outcomes and opioid consumption patterns. A substudy analysis will also be conducted with high-density electroencephalography (72-channel system) to identify neural abnormalities associated with delirium and Mild Cognitive Impairment at preoperative baseline.

ETHICS AND DISSEMINATION

This study was approved by the University of Michigan Medical School Institutional Review Board (HUM00218290). An independent data and safety monitoring board has also been empanelled and has approved the clinical trial protocol and related documents. Trial methodology and results will be disseminated via clinical and scientific journals along with social and news media.

TRIAL REGISTRATION NUMBER

NCT05574400.

Association between Coffee Consumption and Brain MRI Parameters in the Hamburg City Health Study

Despite associations of regular coffee consumption with fewer neurodegenerative disorders, its association with microstructural brain alterations is unclear. To address this, we examined the association of coffee consumption with brain MRI parameters representing vascular brain damage, neurodegeneration, and microstructural integrity in 2316 participants in the population-based Hamburg City Health Study. Cortical thickness and white matter hyperintensity (WMH) load were measured on FLAIR and T1-weighted images. Microstructural white matter integrity was quantified as peak width of skeletonized mean diffusivity (PSMD) on diffusion-weighted MRI. Daily coffee consumption was assessed in five groups (<1 cup, 1-2 cups, 3-4 cups, 5-6 cups, >6 cups). In multiple linear regressions, we examined the association between brain MRI parameters and coffee consumption (reference group <1 cup). After adjustment for covariates, 3-4 cups of daily coffee were associated with lower PSMD (p = 0.028) and higher cortical thickness (p = 0.015) compared to <1 cup. Moreover, 1-2 cups per day was also associated with lower PSMD (p = 0.022). Associations with WMH load or other groups of coffee consumption were not significant (p > 0.05). The findings indicate that regular coffee consumption is positively associated with microstructural white matter integrity and cortical thickness. Further research is necessary to determine longitudinal effects of coffee on brain microstructure.

Self-reported sleepiness associates with greater brain and cortical volume and lower prevalence of ischemic covert brain infarcts in a community sample

STUDY OBJECTIVES

We evaluated if self-reported sleepiness was associated with neuroimaging markers of brain aging and ischemic damage in a large community-based sample.

METHODS

Participants from the Framingham Heart Study Offspring cohort (n = 468, 62.5 ± 8.7 years old, 49.6%M) free of dementia, stroke, and neurological diseases, completed sleep questionnaires and polysomnography followed by magnetic resonance imaging (MRI), 3 years later on average. We used linear and logistic regression models to evaluate the associations between Epworth Sleepiness Scale (ESS) scores and total brain, cortical and subcortical gray matter, and white matter hyperintensities volumes, and the presence of covert brain infarcts.

RESULTS

Higher sleepiness scores were associated with larger total brain volume, greater cortical gray matter volume, and a lower prevalence of covert brain infarcts, even when adjusting for a large array of potential confounders, including demographics, sleep profiles and disorders, organic health diseases, and proxies for daytime cognitive and physical activities. Interactions indicated that more sleepiness was associated with larger cortical gray matter volume in men only and in APOE ε4 noncarriers, whereas a trend for smaller cortical gray matter volume was observed in carriers. In longitudinal analyses, those with stable excessive daytime sleepiness over time had greater total brain and cortical gray matter volumes, whereas baseline sleepiness scores were not associated with subsequent atrophy or cognitive decline.

CONCLUSION

Our findings suggest that sleepiness is not necessarily a marker of poor brain health when not explained by diseases or sleep debt and sleep disorders. Rather, sleepiness could be a marker of preserved sleep-regulatory processes and brain health in some cases.

Associations between urinary caffeine and caffeine metabolites and cognitive function in older adults

BACKGROUND

The effects of caffeine on cognitive impairment have not been conclusively determined. This study aimed to objectively assess the correlation between the urinary caffeine and caffeine metabolites and cognitive decline in older adults.

METHODS

Data on urinary caffeine and caffeine metabolites and the cognitive performance of participants aged 60 years and older were extracted from the National Health and Nutrition Examination Surveys 2011-2014. Binary logistic regression and restricted cubic splines (RCS) analyses were used to evaluate the association between urinary caffeine and caffeine metabolites and cognitive performance.

RESULTS

Eight hundred twenty-seven individuals were enrolled in this cross-sectional study. We observed that 1-methylxanthine, 3-methylxanthine, 7-methylxanthine, 1,3-dimethylxanthine, 1,7-dimethylxanthine, and 3,7-dimethylxanthine levels were significantly and inversely associated with cognitive decline. The RCS results suggested an approximately linear dose-response relationship between the aforementioned metabolites and cognitive performance. Moreover, the effects of urinary caffeine and caffeine metabolites on cognitive function assessed using the AFT were more evident in men.

CONCLUSIONS

Our study suggested that urinary caffeine and caffeine metabolite levels were associated with a reduced risk of cognitive impairment in a linear manner, especially in men.

Neuroprotective Effect of Caffeine in Alzheimer's Disease

Alzheimer’s disease (AD) is the leading cause of dementia, predicted to be the most significant health burden of the 21st century, with an estimated 131.5 million dementia patients by the year 2050. This review aims to provide an overview of the effect of caffeine on AD and cognition by summarizing relevant research conducted on this topic. We searched the Web of Science core collection and PubMed for studies related to the effect of caffeine on AD and cognition using title search terms: caffeine; coffee; Alzheimer’s; cognition. There is suggestive evidence from clinical studies that caffeine is neuroprotective against dementia and possibly AD (20 out of 30 studies support this), but further studies, such as the “ideal” study proposed in this review, are required to prove this link. Clinical studies also indicate that caffeine is a cognitive normalizer and not a cognitive enhancer. Furthermore, clinical studies suggest the neuroprotective effect of caffeine might be confounded by gender. There is robust evidence based on in vivo and in vitro studies that caffeine has neuroprotective properties in AD animal models (21 out of 22 studies support this), but further studies are needed to identify the mechanistic pathways mediating these effects.

High coffee consumption, brain volume and risk of dementia and stroke

BACKGROUND

Coffee is a highly popular beverage worldwide, containing caffeine which is a central nervous system stimulant.

OBJECTIVES

We examined whether habitual coffee consumption is associated with differences in brain volumes or the odds of dementia or stroke.

METHODS

We conducted prospective analyses of habitual coffee consumption on 398,646 UK Biobank participants (age 37-73 years), including 17,702 participants with MRI information. We examined the associations with brain volume using covariate adjusted linear regression, and with odds of dementia (4,333 incident cases) and stroke (6,181 incident cases) using logistic regression.

RESULTS

There were inverse linear associations between habitual coffee consumption and total brain (fully adjusted β per cup -1.42, 95% CI -1.89, -0.94), grey matter (β -0.91, 95% CI -1.20, -0.62), white matter (β -0.51, 95% CI -0.83, -0.19) and hippocampal volumes (β -0.01, 95% CI -0.02, -0.003), but no evidence to support an association with white matter hyperintensity (WMH) volume (β -0.01, 95% CI -0.07, 0.05). The association between coffee consumption and dementia was non-linear (P_{non-linearity}= 0.0001), with evidence for higher odds for non-coffee and decaffeinated coffee drinkers and those drinking >6 cups/day, compared to light coffee drinkers. After full covariate adjustment, consumption of >6 cups/day was associated with 53% higher odds of dementia compared to consumption of 1-2 cups/day (fully adjusted OR 1.53, 95% CI 1.28, 1.83), with less evidence for an association with stroke (OR 1.17, 95% CI 1.00, 1.37, p= 0.055).

CONCLUSION

High coffee consumption was associated with smaller total brain volumes and increased odds of dementia.

Caffeine Effect on Cognitive Function during a Stroop Task: fNIRS Study

Acting as a brain stimulant, coffee resulted in heightening alertness, keeping arousal, improving executive speed, maintaining vigilance, and promoting memory, which are associated with attention, mood, and cognitive function. Functional near-infrared spectroscopy (fNIRS) is a noninvasive optical method to monitor brain activity by measuring the absorption of the near-infrared light through the intact skull. This study is aimed at acquiring brain activation during executing task performance. The aim is to explore the effect of coffee on cognitive function by the fNIRS neuroimaging method, particularly on the prefrontal cortex regions. The behavioral experimental results on 31 healthy subjects with a Stroop task indicate that coffee can easily and effectively modulate the execute task performance by feedback information of the response time and accuracy rate. The findings of fNIRS showed that apparent hemodynamic changes were detected in the bilateral VLPFC regions and the brain activation regions varied with different coffee conditions.

Executive Function and Diabetes: A Clinical Neuropsychology Perspective

Objective

Diabetes is a global public health concern. Management of diabetes depends on successful implementation of strategies to alleviate decline in executive functions (EFs), a characteristic of diabetes progression. In this review, we describe recent research on the relationship between diabetes and EF, summarize the existing evidence, and put forward future research directions and applications.

Methods

Herein, we provide an overview of recent studies, to elucidate the relationship between DM and EF. We identified new screening objectives, management tools, and intervention targets for diabetes management. We also discuss the implications for clinical practice.

Results

In both types 1 and 2 diabetes mellitus (DM), hyperglycemia substantially impairs EF in people of all age groups and ethnicities. Hypoglycemia can similarly impair EF. Interestingly, a decline in EF contributes to DM progression. Glucose dysregulation and EF decline exacerbate each other in a vicious cycle: poor blood glucose control, impaired EF, diabetes management task failure, then back to poor blood glucose control. Many pathophysiological indexes (e.g., obesity, metabolic index, inflammatory and immune factors), neuropsychological indexes (e.g., compliance, eating habits, physical exercise, sleep, and depression), and genetic factors are changed by this pathological interaction between DM and EF. These changes can provide insight into the pathophysiological mechanisms of diabetes-related EF decline.

Conclusion

Further studies, including large-scale prospective and randomized controlled trials, are needed to elucidate the mechanism of the interaction between diabetes and EF and to develop novel strategies for breaking this cycle.

Habitual tea drinking modulates brain efficiency: evidence from brain connectivity evaluation

The majority of tea studies have relied on neuropsychological measures, and much fewer on neuroimaging measures, especially for interregional connections. To date, there has been no exploration of the effect of tea on system-level brain networks. We recruited healthy older participants to two groups according to their history of tea drinking frequency and investigated both functional and structural networks to reveal the role of tea drinking on brain organization. The results showed that tea drinking gave rise to the more efficient structural organization, but had no significant beneficial effect on the global functional organization. The suppression of hemispheric asymmetry in the structural connectivity network was observed as a result of tea drinking. We did not observe any significant effects of tea drinking on the hemispheric asymmetry of the functional connectivity network. In addition, functional connectivity strength within the default mode network (DMN) was greater for the tea-drinking group, and coexistence of increasing and decreasing connective strengths was observed in the structural connectivity of the DMN. Our study offers the first evidence of the positive contribution of tea drinking to brain structure and suggests a protective effect on age-related decline in brain organisation.