Interactive effects of diabetes and impaired kidney function on cognitive performance in old age: a population-based study

Diagnostic, Prognostic, and Mechanistic Biomarkers of Diabetes Mellitus-Associated Cognitive Decline

Cognitive dysfunctions such as mild cognitive impairment (MCI), Alzheimer’s disease (AD), and other forms of dementia are recognized as common comorbidities of type 2 diabetes mellitus (T2DM). Currently, there are no disease-modifying therapies or definitive clinical diagnostic and prognostic tools for dementia, and the mechanisms underpinning the link between T2DM and cognitive dysfunction remain equivocal. Some of the suggested pathophysiological mechanisms underlying cognitive decline in diabetes patients include hyperglycemia, insulin resistance and altered insulin signaling, neuroinflammation, cerebral microvascular injury, and buildup of cerebral amyloid and tau proteins. Given the skyrocketing global rates of diabetes and neurodegenerative disorders, there is an urgent need to discover novel biomarkers relevant to the co-morbidity of both conditions to guide future diagnostic approaches. This review aims to provide a comprehensive background of the potential risk factors, the identified biomarkers of diabetes-related cognitive decrements, and the underlying processes of diabetes-associated cognitive dysfunction. Aging, poor glycemic control, hypoglycemia and hyperglycemic episodes, depression, and vascular complications are associated with increased risk of dementia. Conclusive research studies that have attempted to find specific biomarkers are limited. However, the most frequent considerations in such investigations are related to C reactive protein, tau protein, brain-derived neurotrophic factor, advanced glycation end products, glycosylated hemoglobin, and adipokines.

A survey of cognitive function in peritoneal dialysis patients

INTRODUCTION

The aim of this study was to investigate how peritoneal dialysis and other influencing factors affect patients' cognitive function.

METHODS

The 85 subjects in the study group were regular patients in our center. The control group included 88 age and gender matched healthy individuals who were with normal renal function. The study subjects' cognitive levels and related factors were analyzed using several screening instruments: the cognitive function was measured using the Montreal Cognitive Assessment Scale and statistical analysis was conducted based on the relevant data.

RESULTS

The results showed that cognitive impairment was higher in peritoneal dialysis patients than in non-dialysis subjects. Age and educational background were single factors that affected cognitive function, which was more likely to be impaired at a higher age level and/or a lower educational level.

CONCLUSION

Cognitive function can be impaired by peritoneal dialysis, and age and education levels are influencing factors.

The Use of Serum Matrix Metalloproteinases in Cerebral Amyloid Angiopathy-Related Intracerebral Hemorrhage and Cognitive Impairment

BACKGROUND

Neuroimaging has played a primary role in predicting intracerebral hemorrhage (ICH) recurrence of cerebral amyloid angiopathy (CAA); however, the utilities of biomarkers in CAA-related ICH and cognitive impairment remain unexplored.

OBJECTIVE

To investigate the correlations of serum levels of matrix metalloproteinase-2 (MMP-2), MMP-3, and MMP-9 with CAA-related MRI markers, ICH recurrence, and cognitive status.

METHODS

68 cases with first probable CAA-ICH and 69 controls were recruited. Clinical and imaging data were obtained at baseline and serum MMPs in the acute phase were measured by Luminex multiplex assays. Cognitive status was assessed with the Chinese version of Mini-Mental State Examination within 10-14 days after ICH onset.

RESULTS

Serum MMP-2 level was significantly lower in CAA-ICH patients than controls while MMP-9 was significantly higher. In CAA-ICH patients, MMP-3 level was significantly associated with lobar cerebral microbleeds count after adjusting age, sex, and hypertension (adjusted coefficient 0.368, 95%CI 0.099-0.637, p = 0.008). During a median follow-up of 2.4 years, higher level of MMP-2 predicted lower CAA-ICH recurrence after adjusting age (adjusted HR 0.326, 95%CI 0.122-0.871, p = 0.025), ICH volume (adjusted HR 0.259, 95%CI 0.094-0.715, p = 0.009), total MRI burden of SVD score (adjusted HR 0.350, 95%CI 0.131-0.936, p = 0.037) respectively. Besides, higher level of MMP-2 was significantly associated with decreased risk of cognitive impairment independent of age and ICH volume (adjusted OR 0.054, 95%CI 0.005-0.570, p = 0.015).

CONCLUSION

Serum MMP-2 in acute phase might be a promising biomarker to predict CAA-ICH recurrence and to evaluate the risk of cognitive impairment.

Risk Factors and Clinical Outcomes of Cognitive Impairment in Diabetic Patients Undergoing Peritoneal Dialysis

INTRODUCTION

Cognitive impairment (CI) is common in patients with CKD or diabetes mellitus (DM). However, the relevance between DM and CI in diabetic patients undergoing peritoneal dialysis (PD) has not been clearly established. This study aimed to explore the role of DM in CI, the association of glycemic control with CI, and clinical outcomes of CI in diabetic PD patients.

METHODS

Continuous ambulatory PD (CAPD) patients followed up in our PD center between 2014 and 2016 were enrolled. The participants were followed until an endpoint was reached or December 2017. Demographic data and clinical characteristics were collected, and laboratory parameters were measured. The Montreal Cognitive Assessment (MoCA) was used to evaluate global cognitive function, and a score of <26 was considered to indicate CI. A propensity score matching according to age, gender, and mean arterial pressure was conducted between the DM and non-DM groups.

RESULTS

A total of 913 CAPD patients were enrolled, of whom 186 (20.4%) had diabetes. After appropriate matching, 175 patients in the DM group and 270 patients in the non-DM group were included. Patients with diabetes had a higher prevalence of CI and lower scores for visuospatial/executive function, naming, language, delayed recall, and orientation. Higher HbA1c (odds ratio [OR], 1.547; 95% confidence interval [95% CI], 1.013-2.362) and cardiovascular disease (CVD; OR, 2.926; 95% CI, 1.139-7.516) significantly correlated with a risk of CI in diabetic patients. During a median of 26.0 (interquartile range 13.5-35.6) months of follow-up, diabetic patients with CI demonstrated a significantly lower survival rate than those without CI, and CI was an independent risk factor for mortality after adjustment (hazard ratio, 7.224; 95% CI, 1.694-30.806). However, they did not show worse technique survival or higher peritonitis rate than patients without CI.

CONCLUSIONS

HbA1c and CVD are independent risk factors for CI in diabetic patients undergoing CAPD, and CI is independently associated with a higher risk of mortality.

Kidney function and dementia risk in community-dwelling older adults: the Shanghai Aging Study

BACKGROUND

Association between kidney dysfunction and dementia has been studied in western cohorts, but with inconsistent conclusions which may be due to the different measurements of kidney function. We aim to verify the hypothesis that lower levels of kidney function would be associated with increased risk of incident dementia in Chinese elderly.

METHODS

One thousand four hundred twelve dementia-free participants aged 60 years or older from the Shanghai Aging Study were enrolled and followed up for 5.3 years on average. Glomerular filtration rate (GFR) was calculated by using combined creatinine-cystatin C CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation. Diagnoses of incident dementia and Alzheimer's disease (AD) were established using DSM-IV and NINCDS-ADRDA criteria based on medical, neurological, and neuropsychological examinations to each participant. Cox proportional regression was used to analyze the association of baseline GFR_crcys levels with incident dementia/AD, adjusting age, gender, education years, APOE-ε4, diabetes, hypertension, baseline Mini-Mental State Examination score, and proteinuria.

RESULTS

A total of 113 (8%) and 84 (7%) participants developed dementia and AD. Comparing to participants with high GFR_crcys (≥ 80 ml/min/1.73 m²), participants with low (< 67 ml/min/1.73 m²) and moderate GFR_crcys (67 ≤ GFR < 80 ml/min/1.73 m²) had increased risk of incident dementia with hazard ratios (HRs) of 1.87 (95% CI 1.02-3.44) and 2.19 (95% CI 1.21-3.95) after adjustment for confounders, respectively. Low (HR = 2.27 [95%CI 1.10-4.68]) and moderate (HR = 2.14 [95% CI 1.04-4.40]) GFR_crcys at baseline was also independently associated with incident AD after adjustments when comparing to high GFR_crcys. The significant association between GFR_crcys and dementia risk was observed in female but not in male participants.

CONCLUSIONS

GFR_crcys may be considered as a marker of an individual's vulnerability to the increased risk of cognitive decline.

Informal Caregiving, Poor Mental Health, and Subjective Cognitive Decline: Results From a Population-Based Sample

The current study examined potential gender differences in the associations between informal caregiving, poor mental health, and subjective cognitive decline (SCD). Data were obtained from the U.S. Behavioral Risk Factor Surveillance System (N = 16,042; 9,410 women, 6,632 men). Multivariate linear and logistic regression models were used to obtain adjusted βs and odds ratios (ORs), and 95% confidence intervals (CIs) depicting the association between informal caregiving, poor mental health, and SCD overall and by gender. Caregiving was positively associated with poor mental health among men (adjusted β = 2.60; 95% CI [2.59, 2.62]) and women (adjusted β = 0.40; 95% CI [0.23, 0.57]). Poor mental health was positively associated with SCD among men (adjusted OR = 1.05; 95% CI [1.02, 1.08]) and women (adjusted OR = 1.07; 95% CI [1.04, 1.10]). Poor mental health may be associated with SCD, irrespective of gender, and additional studies are needed that will identify key variables influencing SCD among male and female informal caregivers. [Journal of Gerontological Nursing, 46(12), 31-41.].

Cystatin C promotes cognitive dysfunction in rats with cerebral microbleeds by inhibiting the ERK/synapsin Ia/Ib pathway

Although higher serum level of cystatin C (CysC) was observed in patients with cerebral microbleeds, its associated role in the disease has not been elucidated. In this work, a rat model of cerebral microbleeds was created with the aim of investigating effects of CysC on cognitive function in rats with cerebral microbleeds and the underlying mechanism. Serum samples of patients with cerebral microbleeds and healthy people of the same age were collected. Levels of cystatin C expression in these samples were measured using CysC kits. Moreover, 48 spontaneously hypertensive rats (SHRs) bred under specific pathogen-free (SPF) conditions were randomly divided into 4 groups: sham surgery control group (sham), model group (CMB), model + empty vector control group (CMB + vehicle), and model + cystatin C overexpression group (CMB + CysC). Expression levels of CysC in hippocampus of rats in each group were measured by western blot analysis. The Y-maze was used to evaluate cognitive function of rats. Hippocampal long-term potentiation (LTP) in rats was assessed by the electrophysiological assay. Alterations in levels of p-ERK1/2 and p-synapsin Ia/b proteins associated with cognitive function were identified by western blot analysis. The serum levels of CysC in patients with cerebral microbleeds were significantly upregulated (P<0.001). After injection of CysC, its expression levels in rat hippocampus were significantly increased (P<0.001), which enhanced the decline in learning and memory function, as well as the decrease of LTP in the rat model of cerebral microbleeds (P<0.001). Western blot results showed that injection of CysC further reduced the levels of p-ERK1/2 and p-synapsin Ia/b in the rat model of microbleeds (P<0.001). CysC was up regulated in serum of patients with cerebral microbleeds. It promoted cognitive dysfunction in rats with microbleeds by inhibiting ERK/synapsin Ia/Ib pathway.

Impact of periventricular hyperintensities and cystatin C on different cognitive domains in the population of non-demented elderly Chinese

OBJECTIVES

To investigate the impact of periventricular hyperintensities and serum cystatin C on mild cognitive impairment to provide a basis for the investigation of the pathogenesis.

METHOD

286 patients enrolled the study and underwent an examination in Shanghai Fifth People's Hospital from June 2017 to June 2018. The participants' cognitive function was evaluated by different cognitive domains using of mini-mental state examination (MMSE), Montreal cognitive assessment (MoCA), auditory verbal learning test, Huashan version (AVLT-H), digit span test (DST), symbol digit modalities test (SDMT), trail making test (TMT) and verbal fluency test (VFT). We measured the levels of serum cystatin C at the department of clinical laboratory in Shanghai Fifth People's Hospital and each subject took an MRI examination in the Department of Radiology of Shanghai Fifth People's Hospital. Multivariate linear regression analyses were used to assess the relationship of cognitive score and the level of cystatin C and periventricular hyperintensities severity. All statistical analyses were performed using the SPSS system.

RESULTS

Among 286 eligible participants, 203 (71.0%) were enrolled to further analysis, including 69 male and 134 female (Mean age 67.93 ± 6.19 years). Significant predictors of severe periventricular hyperintensities (PVH) were older age and hypertension. Significant predictors of severe deep white matter hyperintensities (DWMH) were older age only. PVH severity was independently associated with mild cognitive impairment and that the primary impairment was executive function and processing speed. DWMH had no significant effect on cognitive function. Cystatin C only affected the overall cognitive level, and the relationship with WMH severity was not significant.

CONCLUSIONS

We demonstrated that in the chinese non-demented elderly, the severity of PVH was independent and significant associated with mild cognitive impairment and that the primary impairment was executive capacity and processing speed, while cystatin C may be an independent risk factor for overall cognitive impairment.

Central and peripheral pulse wave velocity and subclinical myocardial stress and damage in older adults

Background

Arterial stiffness independently predicts cardiovascular disease. However, few studies have evaluated the associations of central and peripheral pulse wave velocity (PWV) with biomarkers of both myocardial stress (natriuretic peptide [NT-proBNP]) and damage (high-sensitivity cardiac troponin-T [hs-cTnT]) among persons without cardiac disease.

Methods

We examined 3,348 participants (67–90 years) without prevalent cardiac disease in the Atherosclerosis Risk in Communities (ARIC) Study (2011–13). The cross-sectional associations of PWV quartiles for central arterial segments (carotid-femoral, heart-carotid, heart-femoral) and peripheral artery (femoral-ankle) with NT-proBNP and hs-cTnT were evaluated accounting for potential confounders.

Results

Most PWV measures demonstrated J- or U-shaped associations with the two cardiac biomarkers. The highest (Q4) vs. second lowest (Q2) quartile of central PWV measures (carotid-femoral, heart-carotid, heart-femoral PWV) were associated with higher levels of NT-proBNP independently of demographic characteristics. The associations were less evident for hs-cTnT. These associations were attenuated after adjusting for traditional cardiovascular risk factors, but the heart-carotid PWV-NT-proBNP relationship remained borderline significant (difference in log-NT-proBNP = 0.08 [-0.01, 0.17] in Q4 vs. Q2, p = 0.07). Peripheral PWV demonstrated inverse associations. Higher values of NT-proBNP were seen in the lowest vs. second lowest quartile of all PWV measures.

Conclusions

Central stiffness measures showed stronger associations with cardiac biomarkers (particularly NT-proBNP) than peripheral measures among older adults without cardiac disease. Our findings are consistent with the concept of ventricular-vascular coupling and suggest that central rather than peripheral arterial hemodynamics are more closely related to myocardial stress rather than damage.

Diabetes Management in Older Adults With Chronic Kidney Disease

PURPOSE OF REVIEW

Older adults often live with chronic disease including diabetes and its complications. In this review, we examine the complexity and heterogeneity of older adults with diabetes and chronic kidney disease, explore the nuances in their diabetes-related monitoring, and discuss their best diabetes management.

RECENT FINDINGS

Although there remains an overall lack of studies in older adults with diabetes and chronic kidney disease, recent reports have highlighted their vulnerabilities. These individuals face an increased risk of cognitive impairment and dementia, frailty, dysglycemia, polypharmacy, declining kidney function, and acute kidney injury. Their diabetes management should focus upon safer antihyperglycemic medications, close monitoring, and care individualization. Older adults with diabetes and chronic kidney disease are a complex population who requires careful diabetes management and monitoring. Research efforts might focus on improving the care and outcomes of these patients.

Serum cystatin C, impaired kidney function, and geriatric depressive symptoms among older people living in a rural area: a population-based study

BACKGROUND

The relationship between kidney function and depressive symptoms among elderly people has been rarely investigated in settings of the general population. The aim of our study was to examine the association of serum cystatin C (cysC) and impaired kidney function with geriatric depressive symptoms among older people living in a rural community in China.

METHODS

This population-based cohort study included 1440 individuals (age ≥ 60 years) who were recruited for the Confucius Hometown Aging Project in 2010-2011; of the 1124 persons who were free of depressive symptoms, 669 (59.5%) were re-examined in 2014-2016. At baseline, data on demographics, lifestyle factors, health conditions, and medical history were collected through interviews, clinical examinations, and laboratory tests. We defined impaired kidney function as the cystatin C-based estimated glomerular filtration rate (eGFR_cysC) < 60 ml/min/1.73 m², and depressive symptoms as a score ≥ 5 on the 15-item Geriatric Depression Scale. Data were analyzed using multiple logistic and Cox proportional-hazards models.

RESULTS

Of the 1440 participants, 316 (21.9%) were defined to have geriatric depressive symptoms at baseline. Serum cysC levels of 1.01-1.25 and > 1.25 mg/L (vs. ≤1.00 mg/L) were associated with a multiple-adjusted odds ratio (OR) of 1.41 (95% CI 1.01-1.97) and 3.20 (2.32-4.41), respectively, for having geriatric depressive symptoms (P_trend < 0.001). Of the 669 people who were free of depressive symptoms at baseline, 157 had incident depressive symptoms at the follow-up examination. The multiple-adjusted hazard ratio (HR) for incident depressive symptoms were 2.16 (95% CI 1.43-3.27) for serum cysC > 1.25 mg/L (vs. < 1.00 mg/L). Impaired kidney function was cross-sectionally (multiple-adjusted OR = 2.95; 95% CI 2.22-3.92) and longitudinally (multiple-adjusted HR 1.54; 95% CI 1.03-2.30) associated with an increased risk of geriatric depressive symptoms.

CONCLUSION

Elevated serum cysC levels and impaired kidney function are associated with an increased risk of geriatric depressive symptoms among Chinese older people living in a rural community.

Dietary Patterns Associated with Cognitive Function among the Older People in Underdeveloped Regions: Finding from the NCDFaC Study

Although dietary patterns are crucial to cognitive function, associations of dietary patterns with cognitive function have not yet been fully understood. This cross-sectional study explored dietary patterns associated with cognitive function among the older adults in underdeveloped regions, using 1504 community-dwelling older adults aged 60 and over. Diet was assessed using a food frequency questionnaire and 24-h dietary recall. Factor analysis was used to extract dietary patterns. Global cognitive function was assessed using the Mini-Mental State Examination (MMSE). Two dietary patterns, a “mushroom, vegetable, and fruits” (MVF) pattern and a “meat and soybean products” (MS) pattern, were identified. The MVF pattern, characterized by high consumption of mushrooms, vegetables, and fruits was significantly positively associated with cognitive function (p < 0.05), with an odds ratio of (95% CIs) 0.60 (0.38, 0.94) for cognitive impairment and β (95% CIs) 0.15 (0.02, 0.29) for –log (31-MMSE score). The MS pattern, characterized by high consumption of soybean products and meat, was also associated with better cognitive function, with an odds ratio of 0.47 (95% CIs 0.30, 0.74) for cognitive impairment and β (95% CIs) 0.34 (0.21, 0.47) for –log (31-MMSE score). Our results suggested that both the MVF and MS patterns were positively associated with better cognitive function among older adults in underdeveloped regions.

Early markers of kidney dysfunction and cognitive impairment among older adults

BACKGROUND

Age-related decline in kidney function can be an important risk factor for cognitive impairment in older adults. In this study, we examined several kidney function measures for the association with cognitive function in older adults in hope to identify early and sensitive markers that can be used for the detection or screening for cognitive impairment.

METHODS

A total of 1982 older participants (aged ≥60years) in the 1999-2002 National Health and Nutrition Examination Survey was analyzed for the association between kidney function and cognitive impairment using multivariate logistic regression and general linear models. Cognitive functioning was assessed during the household interview using a version of the Digit Symbol Substitution Test of the Wechsler Adult Intelligence Scale III. In our study, participants with a score of <31, the 25th percentiles of the distribution, or who were unable to complete the sample exercise due to cognitive limitations were classified as having cognitive impairment.

RESULTS

Of 1982 older adults, 503 were having cognitive impairment (weighted prevalence, 15.38%). Among the kidney function measures that we examined, the levels of serum cystatin C and urinary albumin were found being significantly associated with cognitive impairment after adjusting for age, sex, race/ethnicity, poverty status, education, physical activity, BMI, cigarette smoking, and alcohol consumption. Cognitive functioning scores were significantly decreasing with increasing levels of kidney dysfunction markers.

CONCLUSION

Serum cystatin C and urinary albumin that are early markers of chronic kidney disease might serve as early and effective markers for cognitive decline in older adults. Mechanisms underlying the observed association need to be further characterized.

Dietary Diversity and Cognitive Function among Elderly People: A Population-Based Study

OBJECTIVES

To explore associations of dietary diversity with cognitive function among Chinese elderly.

DESIGN

This cross-sectional study was conducted in 2011-2012, data were analyzed using multiple linear regression and logistic regression models.

SETTING

community-based setting in the 23 provinces in China.

SUBJECTS

8,571 elderly participants, including 2984 younger elderly aged 65-79 and 5587 oldest old aged 80+ participated in this study.

MEASUREMENT

Intake frequencies of food groups was collected and dietary diversity (DD) was assessed based on the mean of DD score. Cognitive function was assessed using the Chinese version of Mini-Mental State Examination (MMSE), and cognitive impairment was defined using education-based cutoffs. Information about socio-demographics, lifestyles, resilience and health status was also collected.

RESULTS

Poor dietary diversity was significantly associated with cognitive function, with β (95% CI) of -0.11(-0.14, -0.08) for -log (31-MMSE score) and odds ratio (95% CI) of 1.29 (1.14, 1.47) for cognitive impairment. Interaction effect of age with DD was observed on cognitive impairment (P interaction=0.018), but not on -log (31-MMSE score) (P interaction=0.08). Further separate analysis showed that poor DD was significantly associated with increased risk of cognitive impairment in the oldest old (p<0.01), with odds ratio (95% CI) of 1.34 (1.17, 1.54), while not in the younger elderly (p>0.05), with OR (95% CI) being 1.09 (0.80, 1.47) in the fully adjusted model. Similar results were obtained when DD was categorized into four groups.

CONCLUSIONS

Poor dietary diversity was associated with worse global cognitive function among Chinese elderly, and particularly for the oldest old. This finding would be very meaningful for prevention of cognitive impairment.